Otology & Neurotology 35:918Y921 Ó 2014, Otology & Neurotology, Inc.
The Factors Associated With Tumor Stability Observed With Conservative Management of Intracanalicular Vestibular Schwannoma *Jong Dae Lee, *Moo Kyun Park, †Jong Sei Kim, and †Yang-Sun Cho *Department of Otorhinolaryngology-Head and Neck Surgery, Soonchunhyang University College of Medicine, Bucheon; and ÞDepartment of Otorhinolaryngology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
larger in size than the median showed a significantly higher rate of tumor growth. In terms of the initial hearing levels of ICVS according to the Consensus Meeting Guidelines, five patients were classified as Class A (normal hearing) and six patients were classified as Class B. Only one patient among patients with useful hearing (Classes A and B) showed tumor growth. The follow-up hearing levels of all Class A patients were preserved; however, all Class B patients deteriorated to Class C. Conclusion: Patients with ICVS showed favorable results with conservative management. Among them, patients with small tumors and normal hearing showed a good prognosis. Key Words: IntracanalicularVObservationVVestibular schwannoma.
Objective: Periodic observation with imaging is an acceptable option for patients with small vestibular schwannomas (VSs). The objective of this study was to evaluate the outcome of conservative management of intracanalicular VSs (ICVSs). Methods: We reviewed 31 patients who were followed up for more than 1 year among patients diagnosed as having VS limited to the internal auditory canal. The median follow-up period was 31 months (range, 12Y84 mo). We analyzed the patients’ clinical features, clinical courses, and audiologic changes. Results: The most frequent initial presenting symptom in patients with ICVS was hearing loss, and one-half of the patients (8 of 16) had a history of sudden hearing loss. Seven patients (22.5%) showed tumor growth during the follow-up period. When we considered the initial tumor size in ICVS, the patients
Otol Neurotol 35:918Y921, 2014.
The widespread use of magnetic resonance imaging (MRI) scan and increased awareness of vestibular schwannoma (VS) have led to an increased diagnosis of intracanalicular VS (ICVS). There are three treatment modalities for VS: microsurgery, stereotactic radiotherapy, and conservative management such as observation, and controversy exists over which treatment is the best strategy for ICVS (1). A concern about tumor growth and hearing deterioration during observation often motivate active treatments such as surgery or stereotactic radiotherapy more preferable. Moreover, failure to follow up is a problem with observation strategy (2). On the other hand, the benefits of conservative managements include the avoidance of
treatment complications and relief from a financial burden of further treatment. Therefore, observation with periodic imaging follow-up has emerged as an acceptable option for patients with ICVS (3Y5). In an effort to promote a uniform standard for reporting clinical results in patients with VS, a guideline from the Consensus Meeting on Systems for Reporting Results in Acoustic Neuroma was established in 2001 (6) as a modification of the American Academy of Otolaryngology and Head and Neck Surgery (AAO-HNS) classification (7). The objective of this study was to evaluate the outcome of conservative management of ICVS, with special reference to initial hearing level using the Consensus Meeting Guidelines.
Address correspondence and reprint requests to Yang-Sun Cho, M.D., Ph.D., Department of Otorhinolaryngology, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50 Irwon-dong, Gangnam-gu, Seoul 135-710, Korea; E-mail: [email protected] This study was supported by a grant from the Korean Health Technology R&D Project, Ministry of Health & Welfare, Republic of Korea (A121575), and in part by the Soonchunhyang University Research Fund. The authors disclose no conflicts of interest.
MATERIALS AND METHODS We retrospectively reviewed the medical records and MRI studies of 31 patients who were diagnosed as having ICVS and managed conservatively at Soonchunhyang University Hospital and Samsung Medical Center between March 2001 to July 2012. The study was approved by the institutional review board
918
Copyright © 2014 Otology & Neurotology, Inc. Unauthorized reproduction of this article is prohibited.
FACTORS ASSOCIATED WITH TUMOR STABILITY of the College of Medicine, Soonchunhyang University and Sungkyunkwan University. We excluded patients with ICVS who were followed up for less than 1 year. Each patient’s clinical findings, growth pattern of the tumor, and audiologic changes were collected. The size of the tumor was measured as the total length along the axis of the internal auditory canal from the porus acusticus to the fundus. Tumor growth was considered significant in cases of an increase 2 mm or more compared with the previous MRI scan. In our study, the audiologic results were compared at diagnosis and at last follow-up. We used the hearing classification of the Consensus Meeting Guidelines in 2001(Table 1). The pure tone average (PTA) was calculated as the mean of hearing thresholds at 0.5, 1, 2, and 4 kHz. Speech discrimination score (SDS) was also obtained using a monosyllable word list. The statistical analysis using the log-rank test and KaplanMeier survival were used to assess tumor growth according to the tumor size, initial hearing. The comparison of tumor size on growth or no growth was analyzed using the Student’s t-test. A value of p G 0.05 indicated a significant difference.
RESULTS There were 18 women and 13 men aged 20 to 74 years (median, 53.8 yr), and median follow-up period was 31 months (range, 12Y84 mo). Hearing loss was the most frequent initial presenting symptom in 16 patients with ICVS and one-half of them (8 of 16) had a history of sudden hearing loss. The second most common symptom was dizziness, followed by tinnitus and headache. Four patients were diagnosed incidentally (Fig. 1). Initial Tumor Size and Growth Seven (22.5%) of 31 patients showed tumor growth during the follow-up period. Among them, six patients demonstrated tumor growth within 1 year from diagnosis, and one patient demonstrated tumor growth within 2 years. Five of these patients underwent microsurgical removal of the tumor using the translabyrinthine approach, and two patients underwent gamma knife therapy (Table 2). Median intracanalicular diameter was 6.8 mm (range, 3Y13 mm). Analysis using median size revealed that all patients (n = 16) with tumor size less than 6.8 mm showed no growth during follow-up; seven (41.1%) of 17 patients
FIG. 1.
919
Initial presenting symptoms in patients with ICVS.
with tumor size more than 6.8 mm showed tumor growth (Fig. 2A). The mean (TSD) initial size of growing tumors (10.4 T 1.3 mm) was significantly larger than that of nongrowing tumors (5.8 T 2.1; p G 0.001). Most of the growing intracanalicular tumors increased in size to extend extrameatally (Table 2). Tumor Growth and Hearing Deterioration According to the Initial Hearing Level In terms of the initial hearing levels of ICVS according to the Consensus Meeting Guidelines, five patients were Class A (normal hearing) and six patients were Class B. The numbers of Class C, D, E, and F patients were 6, 2, 2, and 10, respectively. Whereas six patients among the useless hearing group (Classes CYF) showed tumor growth during the follow-up, only one patient among the useful hearing group (Classes A and B) showed tumor growth (Fig. 2B). The hearing levels of Class A patients were preserved during the follow-up period, but all Class B patients deteriorated in hearing to Class C (Table 3). Of note, one patient in Class F hearing improved to Class B during the follow-up period. As a whole, the hearing preservation rate in patients with ICVS using the Consensus Meeting Guidelines was 45.4% in our study. However, the patients who have Class A hearing showed neither hearing deterioration nor tumor growth. DISCUSSION
TABLE 1. Class A B C D E F
Hearing classification of Consensus Meeting Guidelines PTA (dB)
SDS (%)
0Y20 21Y30 31Y40 41Y60 61Y80 81G
100Y80 79Y70 69Y60 59Y50 49Y40 39Y0
PTA is obtained by averaging four frequencies: 0.5, 1, 2, and 4 kHz. Hearing is classified based on either PTA or SDS, whichever is worse. A better SDS class than PTA class designates the category as one class higher. PTA indicates pure tone average; SDS, speech discrimination score.
It is well known that hearing loss is the most common symptom in patients with VS (8). Hearing loss is typically gradual in onset and is usually unilateral, asymmetric, and sensorineural in nature. On the other hand, sudden hearing loss has been reported to occur in 7% to 26% of patients with VS (8Y10). Although our study included only ICVS, it showed that hearing loss was the most frequent initial presenting symptom, and sudden hearing loss was relatively common. This is consistent with previous studies showing that small tumors tend to trigger sudden hearing loss more frequently than large tumors (11,12). Although surgical resection is the mainstay of management of VS, watchful waiting has emerged as an Otology & Neurotology, Vol. 35, No. 5, 2014
Copyright © 2014 Otology & Neurotology, Inc. Unauthorized reproduction of this article is prohibited.
920
J. D. LEE ET AL. TABLE 2.
Case 1 2 3 4 5 6 7
Summary of patients who showed tumor growth during the observation period
Sex
Age
Hearing (initial)
Hearing (final)
Initial tumor size (mm)
F/U duration until notification of growth (mo)
Final tumor size (mm)
F/U period (mo)
Extrameatal extension
Further treatment
F M M F F M F
46 47 53 52 55 63 67
F C F C F B F
F F D F F C F
11 10 9 11 10 13 9
12 24 12 12 12 6 12
15 16 15 16 13 18 11
36 24 36 24 12 24 12
Yes Yes Yes Yes Yes Yes No
Surgery (TLA) Surgery (TLA) Surgery (TLA) Surgery (TLA) Surgery (TLA) Gamma knife Gamma knife
F/U indicates follow-up; TLA, translabyrinthine approach.
important management option for patients with ICVS. Stangerup et al. (13) reported that 83% of ICVS remained purely intrameatal during the observation period. This was a significantly lower percentage than the extrameatal tumors. We initially chose a conservative management strategy in patients with ICVS and reserved microsurgery or stereotactic radiotherapy for growing tumors. Seven (22.5%) of 31 patients in our study demonstrated a growth and underwent subsequent treatment; five cases underwent microsurgery and two patients underwent stereotactic radiotherapy. O’Reilly et al. (14) reported that the growth of VS was always evident within the first year. In our series, six of 7 patients also demonstrated growth within the first year of follow-up. Bakkouri et al. (15) reported that age, sex, and initial hearing status do not help predict the likelihood of tumor growth. When we considered the initial tumor size in ICVS, the patients with tumors larger in size than the median showed a significantly higher rate of tumor growth. When we analyze the occurrence of tumor growth in terms of initial hearing, only one of 11 patients with useful hearing (Classes A and B) according to the Consensus Meeting Guidelines showed tumor growth during follow-up, whereas six patients with useless initial hearing (Classes CYF) demonstrated tumor growth. Although the difference was not statistically significant because of the small sample size, the patients with useful hearing have shown a tendency toward a stable size during the follow-up period. Hearing preservation is an important goal in the management of ICVS. Reported rates of hearing preservation vary widely according to the used management for the hearing preservation options available for ICVS. Several
FIG. 2.
recent studies have reported that preservation rates of useful hearing range from 41% to 74% during the observation period (16Y18). Hearing preservation rates after stereotactic radiotherapy for VS vary widely, ranging from 41% to 76% (18,19). Hearing preservation rates after microsurgery, such as the middle fossa approach, have been reported in the literature to range from 20% to 85% (20,21). However, a meaningful comparison among the series has been difficult because grading of hearing outcomes has not always been consistent. In the AAOHNS guideline (1995), the useful hearing included Class A (30 dB PTA and 70% SDS) and Class B (50 dB PTA and 50% SDS). Although the hearing preservation rate in our study was 81.2% according to the AAO-HNS guideline, the hearing preservation rate using the Consensus Meeting Guidelines was 45.4%. Factors that predict the chance of hearing preservation may assist in decisions of management planning for ICVS. Stangerup et al. (22) reported that patients with 100% speech discrimination at diagnosis are more likely to maintain good hearing during the long-term follow-up. In our study, all patients with Class A hearing (defined as an average hearing of 20 dB PTA and an 80% maximum SDS or better) preserved their Class A hearing and showed no tumor growth during the observation period. However, all patients with Class B hearing (defined as a 30-dB PTA average and a 70% maximum SDS) showed deterioration to Class C hearing, and one of six patients showed tumor growth. Thus, the prognoses after observation were clearly different between Classes A and B in our series, although all belonged to Class A of the AAOHNS guidelines. Based on our results, we recommend a
Kaplan-Meier plot of tumor growth for tumor size (A) and hearing (B).
Otology & Neurotology, Vol. 35, No. 5, 2014
Copyright © 2014 Otology & Neurotology, Inc. Unauthorized reproduction of this article is prohibited.
FACTORS ASSOCIATED WITH TUMOR STABILITY TABLE 3.
Usefulness of hearing
Characteristics of patients according to the Consensus Meeting Guidelines
Hearing classification No. No. Hearing Follow-up (initial) cases growths change (n) (range) (mo)
Useful (n = 11) A (normal) B Useless (n = 20) C
5 6 6
0 1 2
D E
2 2
0 0
F
10
4
AYA (5) BYC (6) CYC (4) CYF (2) DYF (2) EYE (1) EYD (1) FYB (1) FYD (2) FYF (7)
5.
6.
33 (12È84) 26 (12È70)
7.
8.
9.
conservative approach in patients with normal hearing (Class A) at the time of diagnosis. A limitation of our study is the small number of enrolled patients to make a sufficient conclusion. However, our study showed the importance of using the Consensus Meeting Guidelines in analyzing the outcome and adds evidence on conservative approach for patients with ICVS for which only rare data are available from Asian countries.
10.
11. 12. 13. 14.
CONCLUSION In summary, our patients with ICVS showed favorable results with conservative management. Our data also demonstrate that the patients with smaller than 6.8 mm or Class A (normal hearing), who might be candidates for hearing preservation microsurgery or stereotactic radiotherapy, showed no growth, and all preserved their hearing during the follow-up period.
15.
16.
17.
18.
REFERENCES 1. Quesnel AM, McKenna MJ. Current strategies in management of intracanalicular vestibular schwannoma. Curr Opin Otolaryngol Head Neck Surg 2011;19:335Y40. 2. Hillman TA, Chen DA, Quigley M, Arriaga MA. Acoustic tumor observation and failure to follow-up. Otolaryngol Head Neck Surg 2010;142:400Y4. 3. Godefroy WP, Kaptein AA, Vogel JJ, van der Mey AG. Conservative treatment of vestibular schwannoma: a follow-up study on clinical and quality-of-life outcome. Otol Neurotol 2009;30:968Y74. 4. Hajioff D, Raut VV, Walsh RM, et al. Conservative management of
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20. 21.
22.
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vestibular schwannomas: third review of a 10-year prospective study. Clin Otolaryngol 2008;33:255Y9. Whitehouse K, Foroughi M, Shone G, Hatfield R. Vestibular schwannomasVwhen should conservative management be reconsidered? Br J Neurosurg 2010;24:185Y90. Kanzaki J, Tos M, Sanna M, Moffat DA, Monsell EM, Berliner KI. New and modified reporting systems from the consensus meeting on systems for reporting results in vestibular schwannoma. Otol Neurotol 2003;24:642Y8. American Academy of OtolaryngologyYHead and Neck Surgery Foundation, Inc. Committee on Hearing and Equilibrium Guidelines for the evaluation of hearing preservation in acoustic neuroma (vestibular schwannoma). Otolaryngol Head Neck Surg 1995;113: 179Y80. Stucken EZ, Brown K, Selesnick SH. Clinical and diagnostic evaluation of acoustic neuromas. Otolaryngol Clin North Am 2012;45: 269Y84. Aslan A, De Donato G, Balyan FR, et al. Clinical observations on coexistence of sudden hearing loss and vestibular schwannoma. Otolaryngol Head Neck Surg 1997;117:580Y2. Sauvaget E, Kici S, Kania R, Herman P, Tran Ba Huy P. Sudden sensorineural hearing loss as a revealing symptom of vestibular schwannoma. Acta Otolaryngol 2005;125:592Y5. Lee JD, Lee BD, Hwang SC. Vestibular schwannoma in patients with sudden sensorineural hearing loss. Skull Base 2011;21:75Y8. Yanagihara N, Asai M. Sudden hearing loss induced by acoustic neuroma: significance of small tumors. Laryngoscope 1993;103:308Y11. Stangerup SE, Caye-Thomasen P, Tos M, Thomsen J. The natural history of vestibular schwannoma. Otol Neurotol 2006;27:547Y52. O’Reilly B, Murray CD, Hadley DM. The conservative management of acoustic neuroma: a review of forty-four patients with magnetic resonance imaging. Clin Otolaryngol Allied Sci 2000;25:93Y7. Bakkouri WE, Kania RE, Guichard JP, Lot G, Herman P, Huy PT. Conservative management of 386 cases of unilateral vestibular schwannoma: tumor growth and consequences for treatment. J Neurosurg 2009;110:662Y9. Caye-Thomasen P, Dethloff T, Hansen S, Stangerup SE, Thomsen J. Hearing in patients with intracanalicular vestibular schwannomas. Audiol Neurootol 2007;12:1Y12. Pennings RJ, Morris DP, Clarke L, Allen S, Walling S, Bance ML. Natural history of hearing deterioration in intracanalicular vestibular schwannoma. Neurosurgery 2011;68:68Y77. Regis J, Carron R, Park MC, et al. Wait-and-see strategy compared with proactive gamma knife surgery in patients with intracanalicular vestibular schwannomas. J Neurosurg 2010;113:105Y11. Yang I, Aranda D, Han SJ, et al. Hearing preservation after stereotactic radiosurgery for vestibular schwannoma: a systematic review. J Clin Neurosci 2009;16:742Y7. Angeli S. Middle fossa approach: indications, technique, and results. Otolaryngol Clin North Am 2012;45:417Y38. Wang AC, Chinn SB, Than KD, et al. Durability of hearing preservation after microsurgical treatment of vestibular schwannoma using the middle cranial fossa approach. J Neurosurg 2013;119:131Y8. Stangerup SE, Thomsen J, Tos M, Caye-Thomasen P. Long-term hearing preservation in vestibular schwannoma. Otol Neurotol 2010;31:271Y5.
Otology & Neurotology, Vol. 35, No. 5, 2014
Copyright © 2014 Otology & Neurotology, Inc. Unauthorized reproduction of this article is prohibited.
The Factors Associated With Tumor Stability Observed With Conservative Management of Intracanalicular Vestibular Schwannoma *Jong Dae Lee, *Moo Kyun Park, †Jong Sei Kim, and †Yang-Sun Cho *Department of Otorhinolaryngology-Head and Neck Surgery, Soonchunhyang University College of Medicine, Bucheon; and ÞDepartment of Otorhinolaryngology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
larger in size than the median showed a significantly higher rate of tumor growth. In terms of the initial hearing levels of ICVS according to the Consensus Meeting Guidelines, five patients were classified as Class A (normal hearing) and six patients were classified as Class B. Only one patient among patients with useful hearing (Classes A and B) showed tumor growth. The follow-up hearing levels of all Class A patients were preserved; however, all Class B patients deteriorated to Class C. Conclusion: Patients with ICVS showed favorable results with conservative management. Among them, patients with small tumors and normal hearing showed a good prognosis. Key Words: IntracanalicularVObservationVVestibular schwannoma.
Objective: Periodic observation with imaging is an acceptable option for patients with small vestibular schwannomas (VSs). The objective of this study was to evaluate the outcome of conservative management of intracanalicular VSs (ICVSs). Methods: We reviewed 31 patients who were followed up for more than 1 year among patients diagnosed as having VS limited to the internal auditory canal. The median follow-up period was 31 months (range, 12Y84 mo). We analyzed the patients’ clinical features, clinical courses, and audiologic changes. Results: The most frequent initial presenting symptom in patients with ICVS was hearing loss, and one-half of the patients (8 of 16) had a history of sudden hearing loss. Seven patients (22.5%) showed tumor growth during the follow-up period. When we considered the initial tumor size in ICVS, the patients
Otol Neurotol 35:918Y921, 2014.
The widespread use of magnetic resonance imaging (MRI) scan and increased awareness of vestibular schwannoma (VS) have led to an increased diagnosis of intracanalicular VS (ICVS). There are three treatment modalities for VS: microsurgery, stereotactic radiotherapy, and conservative management such as observation, and controversy exists over which treatment is the best strategy for ICVS (1). A concern about tumor growth and hearing deterioration during observation often motivate active treatments such as surgery or stereotactic radiotherapy more preferable. Moreover, failure to follow up is a problem with observation strategy (2). On the other hand, the benefits of conservative managements include the avoidance of
treatment complications and relief from a financial burden of further treatment. Therefore, observation with periodic imaging follow-up has emerged as an acceptable option for patients with ICVS (3Y5). In an effort to promote a uniform standard for reporting clinical results in patients with VS, a guideline from the Consensus Meeting on Systems for Reporting Results in Acoustic Neuroma was established in 2001 (6) as a modification of the American Academy of Otolaryngology and Head and Neck Surgery (AAO-HNS) classification (7). The objective of this study was to evaluate the outcome of conservative management of ICVS, with special reference to initial hearing level using the Consensus Meeting Guidelines.
Address correspondence and reprint requests to Yang-Sun Cho, M.D., Ph.D., Department of Otorhinolaryngology, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50 Irwon-dong, Gangnam-gu, Seoul 135-710, Korea; E-mail: [email protected] This study was supported by a grant from the Korean Health Technology R&D Project, Ministry of Health & Welfare, Republic of Korea (A121575), and in part by the Soonchunhyang University Research Fund. The authors disclose no conflicts of interest.
MATERIALS AND METHODS We retrospectively reviewed the medical records and MRI studies of 31 patients who were diagnosed as having ICVS and managed conservatively at Soonchunhyang University Hospital and Samsung Medical Center between March 2001 to July 2012. The study was approved by the institutional review board
918
Copyright © 2014 Otology & Neurotology, Inc. Unauthorized reproduction of this article is prohibited.
FACTORS ASSOCIATED WITH TUMOR STABILITY of the College of Medicine, Soonchunhyang University and Sungkyunkwan University. We excluded patients with ICVS who were followed up for less than 1 year. Each patient’s clinical findings, growth pattern of the tumor, and audiologic changes were collected. The size of the tumor was measured as the total length along the axis of the internal auditory canal from the porus acusticus to the fundus. Tumor growth was considered significant in cases of an increase 2 mm or more compared with the previous MRI scan. In our study, the audiologic results were compared at diagnosis and at last follow-up. We used the hearing classification of the Consensus Meeting Guidelines in 2001(Table 1). The pure tone average (PTA) was calculated as the mean of hearing thresholds at 0.5, 1, 2, and 4 kHz. Speech discrimination score (SDS) was also obtained using a monosyllable word list. The statistical analysis using the log-rank test and KaplanMeier survival were used to assess tumor growth according to the tumor size, initial hearing. The comparison of tumor size on growth or no growth was analyzed using the Student’s t-test. A value of p G 0.05 indicated a significant difference.
RESULTS There were 18 women and 13 men aged 20 to 74 years (median, 53.8 yr), and median follow-up period was 31 months (range, 12Y84 mo). Hearing loss was the most frequent initial presenting symptom in 16 patients with ICVS and one-half of them (8 of 16) had a history of sudden hearing loss. The second most common symptom was dizziness, followed by tinnitus and headache. Four patients were diagnosed incidentally (Fig. 1). Initial Tumor Size and Growth Seven (22.5%) of 31 patients showed tumor growth during the follow-up period. Among them, six patients demonstrated tumor growth within 1 year from diagnosis, and one patient demonstrated tumor growth within 2 years. Five of these patients underwent microsurgical removal of the tumor using the translabyrinthine approach, and two patients underwent gamma knife therapy (Table 2). Median intracanalicular diameter was 6.8 mm (range, 3Y13 mm). Analysis using median size revealed that all patients (n = 16) with tumor size less than 6.8 mm showed no growth during follow-up; seven (41.1%) of 17 patients
FIG. 1.
919
Initial presenting symptoms in patients with ICVS.
with tumor size more than 6.8 mm showed tumor growth (Fig. 2A). The mean (TSD) initial size of growing tumors (10.4 T 1.3 mm) was significantly larger than that of nongrowing tumors (5.8 T 2.1; p G 0.001). Most of the growing intracanalicular tumors increased in size to extend extrameatally (Table 2). Tumor Growth and Hearing Deterioration According to the Initial Hearing Level In terms of the initial hearing levels of ICVS according to the Consensus Meeting Guidelines, five patients were Class A (normal hearing) and six patients were Class B. The numbers of Class C, D, E, and F patients were 6, 2, 2, and 10, respectively. Whereas six patients among the useless hearing group (Classes CYF) showed tumor growth during the follow-up, only one patient among the useful hearing group (Classes A and B) showed tumor growth (Fig. 2B). The hearing levels of Class A patients were preserved during the follow-up period, but all Class B patients deteriorated in hearing to Class C (Table 3). Of note, one patient in Class F hearing improved to Class B during the follow-up period. As a whole, the hearing preservation rate in patients with ICVS using the Consensus Meeting Guidelines was 45.4% in our study. However, the patients who have Class A hearing showed neither hearing deterioration nor tumor growth. DISCUSSION
TABLE 1. Class A B C D E F
Hearing classification of Consensus Meeting Guidelines PTA (dB)
SDS (%)
0Y20 21Y30 31Y40 41Y60 61Y80 81G
100Y80 79Y70 69Y60 59Y50 49Y40 39Y0
PTA is obtained by averaging four frequencies: 0.5, 1, 2, and 4 kHz. Hearing is classified based on either PTA or SDS, whichever is worse. A better SDS class than PTA class designates the category as one class higher. PTA indicates pure tone average; SDS, speech discrimination score.
It is well known that hearing loss is the most common symptom in patients with VS (8). Hearing loss is typically gradual in onset and is usually unilateral, asymmetric, and sensorineural in nature. On the other hand, sudden hearing loss has been reported to occur in 7% to 26% of patients with VS (8Y10). Although our study included only ICVS, it showed that hearing loss was the most frequent initial presenting symptom, and sudden hearing loss was relatively common. This is consistent with previous studies showing that small tumors tend to trigger sudden hearing loss more frequently than large tumors (11,12). Although surgical resection is the mainstay of management of VS, watchful waiting has emerged as an Otology & Neurotology, Vol. 35, No. 5, 2014
Copyright © 2014 Otology & Neurotology, Inc. Unauthorized reproduction of this article is prohibited.
920
J. D. LEE ET AL. TABLE 2.
Case 1 2 3 4 5 6 7
Summary of patients who showed tumor growth during the observation period
Sex
Age
Hearing (initial)
Hearing (final)
Initial tumor size (mm)
F/U duration until notification of growth (mo)
Final tumor size (mm)
F/U period (mo)
Extrameatal extension
Further treatment
F M M F F M F
46 47 53 52 55 63 67
F C F C F B F
F F D F F C F
11 10 9 11 10 13 9
12 24 12 12 12 6 12
15 16 15 16 13 18 11
36 24 36 24 12 24 12
Yes Yes Yes Yes Yes Yes No
Surgery (TLA) Surgery (TLA) Surgery (TLA) Surgery (TLA) Surgery (TLA) Gamma knife Gamma knife
F/U indicates follow-up; TLA, translabyrinthine approach.
important management option for patients with ICVS. Stangerup et al. (13) reported that 83% of ICVS remained purely intrameatal during the observation period. This was a significantly lower percentage than the extrameatal tumors. We initially chose a conservative management strategy in patients with ICVS and reserved microsurgery or stereotactic radiotherapy for growing tumors. Seven (22.5%) of 31 patients in our study demonstrated a growth and underwent subsequent treatment; five cases underwent microsurgery and two patients underwent stereotactic radiotherapy. O’Reilly et al. (14) reported that the growth of VS was always evident within the first year. In our series, six of 7 patients also demonstrated growth within the first year of follow-up. Bakkouri et al. (15) reported that age, sex, and initial hearing status do not help predict the likelihood of tumor growth. When we considered the initial tumor size in ICVS, the patients with tumors larger in size than the median showed a significantly higher rate of tumor growth. When we analyze the occurrence of tumor growth in terms of initial hearing, only one of 11 patients with useful hearing (Classes A and B) according to the Consensus Meeting Guidelines showed tumor growth during follow-up, whereas six patients with useless initial hearing (Classes CYF) demonstrated tumor growth. Although the difference was not statistically significant because of the small sample size, the patients with useful hearing have shown a tendency toward a stable size during the follow-up period. Hearing preservation is an important goal in the management of ICVS. Reported rates of hearing preservation vary widely according to the used management for the hearing preservation options available for ICVS. Several
FIG. 2.
recent studies have reported that preservation rates of useful hearing range from 41% to 74% during the observation period (16Y18). Hearing preservation rates after stereotactic radiotherapy for VS vary widely, ranging from 41% to 76% (18,19). Hearing preservation rates after microsurgery, such as the middle fossa approach, have been reported in the literature to range from 20% to 85% (20,21). However, a meaningful comparison among the series has been difficult because grading of hearing outcomes has not always been consistent. In the AAOHNS guideline (1995), the useful hearing included Class A (30 dB PTA and 70% SDS) and Class B (50 dB PTA and 50% SDS). Although the hearing preservation rate in our study was 81.2% according to the AAO-HNS guideline, the hearing preservation rate using the Consensus Meeting Guidelines was 45.4%. Factors that predict the chance of hearing preservation may assist in decisions of management planning for ICVS. Stangerup et al. (22) reported that patients with 100% speech discrimination at diagnosis are more likely to maintain good hearing during the long-term follow-up. In our study, all patients with Class A hearing (defined as an average hearing of 20 dB PTA and an 80% maximum SDS or better) preserved their Class A hearing and showed no tumor growth during the observation period. However, all patients with Class B hearing (defined as a 30-dB PTA average and a 70% maximum SDS) showed deterioration to Class C hearing, and one of six patients showed tumor growth. Thus, the prognoses after observation were clearly different between Classes A and B in our series, although all belonged to Class A of the AAOHNS guidelines. Based on our results, we recommend a
Kaplan-Meier plot of tumor growth for tumor size (A) and hearing (B).
Otology & Neurotology, Vol. 35, No. 5, 2014
Copyright © 2014 Otology & Neurotology, Inc. Unauthorized reproduction of this article is prohibited.
FACTORS ASSOCIATED WITH TUMOR STABILITY TABLE 3.
Usefulness of hearing
Characteristics of patients according to the Consensus Meeting Guidelines
Hearing classification No. No. Hearing Follow-up (initial) cases growths change (n) (range) (mo)
Useful (n = 11) A (normal) B Useless (n = 20) C
5 6 6
0 1 2
D E
2 2
0 0
F
10
4
AYA (5) BYC (6) CYC (4) CYF (2) DYF (2) EYE (1) EYD (1) FYB (1) FYD (2) FYF (7)
5.
6.
33 (12È84) 26 (12È70)
7.
8.
9.
conservative approach in patients with normal hearing (Class A) at the time of diagnosis. A limitation of our study is the small number of enrolled patients to make a sufficient conclusion. However, our study showed the importance of using the Consensus Meeting Guidelines in analyzing the outcome and adds evidence on conservative approach for patients with ICVS for which only rare data are available from Asian countries.
10.
11. 12. 13. 14.
CONCLUSION In summary, our patients with ICVS showed favorable results with conservative management. Our data also demonstrate that the patients with smaller than 6.8 mm or Class A (normal hearing), who might be candidates for hearing preservation microsurgery or stereotactic radiotherapy, showed no growth, and all preserved their hearing during the follow-up period.
15.
16.
17.
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Otology & Neurotology, Vol. 35, No. 5, 2014
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