Endotracheal Irradiation of Adenoid Cystic Carcinoma of the Trachea 1 Bernard Percarplo, M.D., John C. Price, M.D., and Patrick Murphy, D.M.D. Management of advanced or recurrent primary tracheal neoplasms has been restricted to palliative external beam irradiation. A patient with recurent adenoid cystic carcinoma of the trachea was recently treated again by combined external irradiation and endotracheal brachytherapy with iridium 192 sources; the results were dramatic without significant normal tissue toxicity. This endotracheal brachytherapy technique might be applied to tracheal tumors of different histology or more limited extent. Ir-I)EX TERMS: (Trachea. carcinoma.
Trachea. therapeutic radiology
Radiology 128:209-210, July 1978
A DENOID CYSTIC CARCINOMA of the trachea is a rare /"'\ tumor usually treated by surgery if it is of sufficiently small size. More extensive tumors have been treated by external beam irradiation with varying results. We recently treated a patient with this tumor using endotracheal irradiation for a portion of the therapy; the results were encouraging. CASE REPORT A.F., a 25-year-old white man, presented to Walter Reed Army Medical Center in January 1973 complaining of dyspnea. For 21/2 years prior he had noticed increasing shortness of breath with frequent respiratory infections, and had scant hemoptysis on two occasions. A chest radiograph suggested a tracheal mass, and bronchoscopy revealed an extensive tumor involving the posterior tracheal wall. The mass extended from the subglottic region to the carina with involvement of the left mainstem bronchus. Multiple biopsies were consistent with adenoid cystic carcinoma. In February and March 1973 he received a midthoracic dose of 4720 rads in 42 days using 6GCO. Therapy was delivered using large fields covering the entire trachea and both mainstem bronchi. Anterior and posterior ports were weighted 6: 1. The patient's symptoms were relieved by therapy. Evaluation by chest radiograph, tracheal tomograms, and bronchoscopy in June 1973 revealed complete resolution of the tumor. The patient did well until October 1976 when he noted the return of severe dyspnea with stridor and one episode of hemoptysis. Tracheal tomography (Fig. 1) indicated narrowing of the lower trachea; bronchoscopy revealed obvious tumor recurrence in the lower third of the trachea with a 3-4mm tracheal lumen. The patient was treated again in November 1976 with small 5 X 7 em anterior wedged fields angled to exclude the thoracic spinal cord. An additional 2980 rads were delivered to the lower trachea in 14 treatments over 20 days using a 4-MeV linear accelerator. The patient's dyspnea improved. Bronchoscopy three weeks after irradiation showed marked reduction of the tumor. An endotracheal tube was modified by the Removable Prosthodontics Division to contain six hollow plastic tubes arranged in its outer circumference (Fig. 2). Three weeks following external irradiation, the tube was inserted via trachostomy into the lower trachea and sutured in place. The six hollow tubes were then afterloaded with 42 seeds of iridium 192 with a total activity of 24 mg Eq. (Fig. 3). The tube remained in place for 34 hours in order to deliver a dose of 2312 rads calculated at 0.5 cm peripheral to the tracheal mucosa. The total dose to the ad-
jacent spinal cord from the implant was less than 200 rads. The patient's dyspnea continued to improve and no tumor mass could be demonstrated by tomography two months following irradiation (Fig. 4). Repeat examinations revealed no evidence of recurrence; the patient is in good health five months after treatment.
DISCUSSION Adenoid cystic carcinoma accounts for less than one third of primary tracheal neoplasms (5). Because of the slow growth of these tumors, symptoms are frequently attributed to chronic bronchitis or asthma (1, 5, 8). Routine chest radiographs are commonly misread as normal, although tracheal narrowing is present and can be readily seen by tomography (4). The treatment of choice for localized lesions is surgery; reasonably good results have been reported (3, 6, 8, 10, 11). Many tracheal tumors, however, are too large, or have invaded adjacent critical tissues, to permit surgery. Radiation therapy has until recently been regarded as having little benefit in the radical or palliative treatment of these patients (3, 5, 7). Many of these previous reviews include patients treated with subcancerocidal doses of radiation. Indeed, the original course of irradiation given our patient should have been more aggressive, using a higher dose to increase the probability of local control. More recently, there have been several reports of prolonged palliation and survival of patients irradiated for extensive unresectable adenoid cystic carcinomas of the trachea (2,9, 11). All these patients received a relatively high dose of external beam irradiation (5000 rads or greater), and several patients had a marked and rapid reduction of tumor mass follOWing therapy similar to our case. However, there has been little reference to the treatment of these tumors by the endotracheal insertion of radioactive sources. For the repeated treatment of our patient, the amount of additional external irradiation was limited by the previous doses delivered to the spinal cord, heart, and lungs. Insertion of endotracheal radioactive iridium sources was easily accomplished; a total dose of almost 5300 rads was delivered to his recurrent tumor with dramatic palliative results. Although few patients with advanced tracheal adenoid cystic carcinoma will be cured by radiotherapy,the use of endotracheal irradiation techniques either as primary therapy or as repeated treatment may produce significant, prolonged palliation.
REFERENCES 1. Baydur A, Gottlieb LS: Adenoid cystic carcinoma (cylindroma) of the trachea masquerading as asthma. JAMA 234:829-831, Nov 1975 2. Bennetts FE: Tracheal tumors. Postgrad Med J 45:446-454, Jul 1969 3. Birt BD: The management of malignant tracheal neoplasms. J Laryngol OtoI84:723-731, Jul1970 4. Cleveland RH, Nice CM, Ziskind J: Primary adenoid cystic carcinoma (cylindroma) of the trachea. Radiology 122:597-600, Mar 1977 5. Hajdu, SI, Huvos AG, Goodner JT, et al: Carcinoma of the trachea. Clinicopathologic study of 41 cases. Cancer 25:1148-1456, Jun 1970 6. Hills EA: Cylindroma of the trachea and left main bronchus. Proc Roy Soc Med 64:221-222, Feb 1971
1 From the Radiation Therapy Service (B.P.); the Division of Otolaryngology, Department of Surgery (J.e.p.); and the Removable Prosthodontics Section, Department of Dentistry (P.M.), Walter Reed Army Medical Center. Washington, D.C. Submitted for publication in September 19, 1977; accepted and revision requested on January 17, 1978. emt
Fig. 1. chea.
BERNARD PERCARPIO AND OTHERS
Recurrent adenoid cystic carcinoma of the tra-
192IRIDIUM SEEDS Endotracheal Tube
Fig. 3. 192.
Endotracheal tube in patient with 42 seedsof iridium
Fig. 4. ment.
Tracheal tomogram 2 months following retreat-
Fig. 2. Modified endotracheal tube with circumferential afterloading tubes.
7. Houston HE,PayneS, Harrison EG,et al: Primary cancers of the trachea. Arch Surg 99: 132-140, Aug 1969 8. Pearson FG, Thompson OW, Weissberg 0, et al.: Adenoid cystic carcinoma of the trachea. Ann Thorac Surg 18:16-29, Jul
1974 9. Richardson JD, Graver F, Trinkle JK: Adenoid cystic carcinoma of the trachea. Thorac Cardiovasc Surg 66:311-314, Aug 1973 10. Vieta, JO, Maier HC: The treatment of adenoid cystic carcinoma (cylindroma) of the respiratory tract by surgery and radiation therapy. Dis Chest 31:493-511, May 1957 11. Zunker HO, Moore RL, Baker DC, et al: Adenoid cystic carcinoma (cylindroma)of the trachea: case report with 9 year follow-up. Cancer 23:699-707, Mar 1969
Department of Therapeutic Radiology Yale University School of Medicine New Haven, Connecticut 06510