Cancer Causes Control (2014) 25:1583–1585 DOI 10.1007/s10552-014-0453-8
LETTER TO THE EDITOR
Seasonal variation in the presentation of thyroid cancer in the USA: an analysis of the Surveillance, Epidemiology and End Results Registry Smith Giri • Ranjan Pathak • Madan Raj Aryal Paras Karmacharya • Vijaya Raj Bhatt • Mike G. Martin
•
Received: 13 June 2014 / Accepted: 31 July 2014 / Published online: 19 August 2014 Ó Springer International Publishing Switzerland 2014
Seasonal variation in diagnosis has been reported in a variety of cancers including acute myeloid leukemia, lymphoma, melanoma, breast cancer and childhood cancers [1–6]. Two studies have investigated the seasonal trends in the presentation of thyroid cancer in the Scandinavian countries, but not in the USA [7, 8]. Understanding the seasonal pattern of diagnosis of thyroid cancer may allow healthcare resource allocation as well as offer insights into disease pathogenesis. We utilized the Surveillance, Epidemiology and End Results (SEER) database to identify all cases of thyroid cancer diagnosed between 1973 and 2011. SEER is a program of the National Cancer Institute (NCI) that provides cancer incidence and survival data from populationbased cancer registries covering about 28 % of the US population [9]. We stratified the identified cases based on
gender and the month of diagnosis. Statistical analysis was conducted using the Statistical Package for Social Sciences: SPSS version 21.0 (IBM Corporation, Armonk, NY, USA). Walter and Elwood modification of the Edwards test was used to determine the monthly distribution of thyroid cancer cases. Chi-square test was utilized to compare the observed seasonal distribution of thyroid cancer to the expected values. A total of 143,746 cases of thyroid cancer were identified during the study period, of which 24.5 % were males. The mean age was 49 ± 16 years. A distinct peak in the adjusted monthly frequency of thyroid cancer was observed in October (Table 1). When stratified by gender, a distinct peak of thyroid cancer was noted in October for females and in November for males (Fig. 1a–c). A significant difference existed in the reporting of thyroid
S. Giri M. G. Martin Department of Medicine, University of Tennessee Health Science Center, Memphis, TN, USA R. Pathak M. R. Aryal P. Karmacharya (&) Department of Medicine, Reading Health System, 6th Avenue and Spruce St, West Reading, PA, USA e-mail: [email protected] V. R. Bhatt Division of Hematology Oncology, University of Nebraska Medical Center, Omaha, NE, USA
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Cancer Causes Control (2014) 25:1583–1585
Table 1 Seasonal variation in thyroid cancer in terms of peak to low ratio stratified by gender Group
Peak month
Peak/low ratio
95 % CI of peak/low ratio
Overall cases
October
1.048
1.032–1.063
Male
November
1.059
1.028–1.091
Female
October
1.042
1.025–1.060
cancer during different seasons, with the maximum cases reported in autumn and the minimum cases in winter (p value \0.001). Our study suggests a distinct seasonal trend in the presentation of thyroid cancers in the US with a significantly higher proportion of cases presenting in October and during autumn. Akslen et al. [7] reported an increase in the diagnosis of thyroid cancer between September and January (late autumn to winter) in a study from Norway. Conversely, Lambe et al. [8] reported an increased number of cases between December and January in Sweden. In comparison to these studies, we observed an earlier peak of reported cases; the variation may be related to the difference in latitude of these regions. Although the precise mechanism of this seasonal variation remains unclear, several hypotheses have been postulated. Thyroid-stimulating hormone, which stimulates growth of thyroid gland, has been found to peak during November and December [10, 11]. Seasonal variation in the mitotic rates of malignant cells has been reported; the growth pattern may be different in various malignant tissues [12, 13]. These possible mechanisms may explain the seasonal variation observed in the incidence of thyroid cancer. Our data have some limitations. It is possible that seasonal patterns of physician visits and timing of diagnostic procedures may be contributing to the observed distribution. Although there is limited data on the seasonal patterns in physician visits in the USA, one previous study has suggested that there is no significant seasonal difference in visits to family physicians [14]. Similarly, the use of Walter and Elwood modification of Edwards test allows us to account for any intrinsic seasonal variation in cancer diagnosis of all types [15]. In conclusion, our study of a large SEER database confirms the distinct seasonal patterns in the distribution of thyroid cancer diagnosis in the USA. Future research should explore the possible mechanisms responsible for the trend. Such investigations have the potential to offer insights into disease pathogenesis.
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Fig. 1 Monthly frequency distribution of diagnosis of thyroid cancer in USA based on SEER 18 registry 1973–2011. a Overall cases, b females only, c males only
Cancer Causes Control (2014) 25:1583–1585 Conflict of interest Authors have no competing interests to disclose.
References 1. Braun MM, Tucker MA, Devesa SS, Hoover RN (1994) Seasonal variation in frequency of diagnosis of cutaneous malignant melanoma. Melanoma Res 4(4):235–241 2. Calip GS, McDougall JA, Wheldon MC, Li CI, De Roos AJ (2013) Evaluation of seasonality in the diagnosis of acute myeloid leukaemia among adults in the United States, 1992–2008. Br J Haematol 160(3):343–350 3. Cohen P, Wax Y, Modan B (1983) Seasonality in the occurrence of breast cancer. Cancer Res 43(2):892–896 4. Gao F, Machin D, Khoo KS, Ng EH (2001) Seasonal variation in breast cancer diagnosis in Singapore. Br J Cancer 84(9): 1185–1187 5. Koutros S, Holford TR, Hahn T et al (2007) Excess diagnosis of non-Hodgkin’s lymphoma during spring in the USA. Leuk Lymphoma 48(2):357–366 6. Ross JA, Severson RK, Swensen AR, Pollock BH, Gurney JG, Robison LL (1999) Seasonal variations in the diagnosis of childhood cancer in the United States. Br J Cancer 81(3):549–553 7. Akslen LA, Southern RB (1998) Seasonal variations in the presentation and growth of thyroid cancer. Br J Cancer 77(7): 1174–1179 8. Lambe M, Blomqvist P, Bellocco R (2003) Seasonal variation in the diagnosis of cancer: a study based on national cancer registration in Sweden. Br J Cancer 88(9):1358–1360
1585 9. Surveillance, Epidemiology, and End Results (SEER) (2014) Program SEER*Stat Database: Incidence—SEER 18 Regs Research Data ? Hurricane Katrina Impacted Louisiana Cases, Nov 2013 Sub (1973–2011 varying)—Linked To County Attributes—Total U.S., 1969–2012 Counties, National Cancer Institute, DCCPS, Surveillance Research Program, Surveillance Systems Branch, released April 2014 (updated 5/7/2014), based on the November 2013 submission. www.seer.cancer.gov 10. Halberg F, Lagoguey M, Reinberg A (1983) Human circannual rhythms over a broad spectrum of physiological processes. Int J Chronobiol 8(4):225–268 11. Leppaluoto J, Sikkila K, Hassi J (1998) Seasonal variation of serum TSH and thyroid hormones in males living in subarctic environmental conditions. Int J Circumpolar Health 57(Suppl 1):383–385 12. Sothern RB, Smaaland R, Moore JG (1995) Circannual rhythm in DNA synthesis (S-phase) in healthy human bone marrow and rectal mucosa. FASEB J 9(5):397–403 13. Haus E, Lakatua DJ, Sackett-Lundeen L (1997) Circannual variation of cell proliferation in lymphoid organs and bone marrow of BDF1 male mice on three lighting regimens. Chronobiol Int 14(4):347–362 14. Pace WD, Dickinson LM, Staton EW (2004) Seasonal variation in diagnoses and visits to family physicians. Ann Fam Med 2(5):411–417 15. Walter SD, Elwood JM (1975) A test for seasonality of events with a variable population at risk. Br J Prev Soc Med 29(1):18–21
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LETTER TO THE EDITOR
Seasonal variation in the presentation of thyroid cancer in the USA: an analysis of the Surveillance, Epidemiology and End Results Registry Smith Giri • Ranjan Pathak • Madan Raj Aryal Paras Karmacharya • Vijaya Raj Bhatt • Mike G. Martin
•
Received: 13 June 2014 / Accepted: 31 July 2014 / Published online: 19 August 2014 Ó Springer International Publishing Switzerland 2014
Seasonal variation in diagnosis has been reported in a variety of cancers including acute myeloid leukemia, lymphoma, melanoma, breast cancer and childhood cancers [1–6]. Two studies have investigated the seasonal trends in the presentation of thyroid cancer in the Scandinavian countries, but not in the USA [7, 8]. Understanding the seasonal pattern of diagnosis of thyroid cancer may allow healthcare resource allocation as well as offer insights into disease pathogenesis. We utilized the Surveillance, Epidemiology and End Results (SEER) database to identify all cases of thyroid cancer diagnosed between 1973 and 2011. SEER is a program of the National Cancer Institute (NCI) that provides cancer incidence and survival data from populationbased cancer registries covering about 28 % of the US population [9]. We stratified the identified cases based on
gender and the month of diagnosis. Statistical analysis was conducted using the Statistical Package for Social Sciences: SPSS version 21.0 (IBM Corporation, Armonk, NY, USA). Walter and Elwood modification of the Edwards test was used to determine the monthly distribution of thyroid cancer cases. Chi-square test was utilized to compare the observed seasonal distribution of thyroid cancer to the expected values. A total of 143,746 cases of thyroid cancer were identified during the study period, of which 24.5 % were males. The mean age was 49 ± 16 years. A distinct peak in the adjusted monthly frequency of thyroid cancer was observed in October (Table 1). When stratified by gender, a distinct peak of thyroid cancer was noted in October for females and in November for males (Fig. 1a–c). A significant difference existed in the reporting of thyroid
S. Giri M. G. Martin Department of Medicine, University of Tennessee Health Science Center, Memphis, TN, USA R. Pathak M. R. Aryal P. Karmacharya (&) Department of Medicine, Reading Health System, 6th Avenue and Spruce St, West Reading, PA, USA e-mail: [email protected] V. R. Bhatt Division of Hematology Oncology, University of Nebraska Medical Center, Omaha, NE, USA
123
1584
Cancer Causes Control (2014) 25:1583–1585
Table 1 Seasonal variation in thyroid cancer in terms of peak to low ratio stratified by gender Group
Peak month
Peak/low ratio
95 % CI of peak/low ratio
Overall cases
October
1.048
1.032–1.063
Male
November
1.059
1.028–1.091
Female
October
1.042
1.025–1.060
cancer during different seasons, with the maximum cases reported in autumn and the minimum cases in winter (p value \0.001). Our study suggests a distinct seasonal trend in the presentation of thyroid cancers in the US with a significantly higher proportion of cases presenting in October and during autumn. Akslen et al. [7] reported an increase in the diagnosis of thyroid cancer between September and January (late autumn to winter) in a study from Norway. Conversely, Lambe et al. [8] reported an increased number of cases between December and January in Sweden. In comparison to these studies, we observed an earlier peak of reported cases; the variation may be related to the difference in latitude of these regions. Although the precise mechanism of this seasonal variation remains unclear, several hypotheses have been postulated. Thyroid-stimulating hormone, which stimulates growth of thyroid gland, has been found to peak during November and December [10, 11]. Seasonal variation in the mitotic rates of malignant cells has been reported; the growth pattern may be different in various malignant tissues [12, 13]. These possible mechanisms may explain the seasonal variation observed in the incidence of thyroid cancer. Our data have some limitations. It is possible that seasonal patterns of physician visits and timing of diagnostic procedures may be contributing to the observed distribution. Although there is limited data on the seasonal patterns in physician visits in the USA, one previous study has suggested that there is no significant seasonal difference in visits to family physicians [14]. Similarly, the use of Walter and Elwood modification of Edwards test allows us to account for any intrinsic seasonal variation in cancer diagnosis of all types [15]. In conclusion, our study of a large SEER database confirms the distinct seasonal patterns in the distribution of thyroid cancer diagnosis in the USA. Future research should explore the possible mechanisms responsible for the trend. Such investigations have the potential to offer insights into disease pathogenesis.
123
Fig. 1 Monthly frequency distribution of diagnosis of thyroid cancer in USA based on SEER 18 registry 1973–2011. a Overall cases, b females only, c males only
Cancer Causes Control (2014) 25:1583–1585 Conflict of interest Authors have no competing interests to disclose.
References 1. Braun MM, Tucker MA, Devesa SS, Hoover RN (1994) Seasonal variation in frequency of diagnosis of cutaneous malignant melanoma. Melanoma Res 4(4):235–241 2. Calip GS, McDougall JA, Wheldon MC, Li CI, De Roos AJ (2013) Evaluation of seasonality in the diagnosis of acute myeloid leukaemia among adults in the United States, 1992–2008. Br J Haematol 160(3):343–350 3. Cohen P, Wax Y, Modan B (1983) Seasonality in the occurrence of breast cancer. Cancer Res 43(2):892–896 4. Gao F, Machin D, Khoo KS, Ng EH (2001) Seasonal variation in breast cancer diagnosis in Singapore. Br J Cancer 84(9): 1185–1187 5. Koutros S, Holford TR, Hahn T et al (2007) Excess diagnosis of non-Hodgkin’s lymphoma during spring in the USA. Leuk Lymphoma 48(2):357–366 6. Ross JA, Severson RK, Swensen AR, Pollock BH, Gurney JG, Robison LL (1999) Seasonal variations in the diagnosis of childhood cancer in the United States. Br J Cancer 81(3):549–553 7. Akslen LA, Southern RB (1998) Seasonal variations in the presentation and growth of thyroid cancer. Br J Cancer 77(7): 1174–1179 8. Lambe M, Blomqvist P, Bellocco R (2003) Seasonal variation in the diagnosis of cancer: a study based on national cancer registration in Sweden. Br J Cancer 88(9):1358–1360
1585 9. Surveillance, Epidemiology, and End Results (SEER) (2014) Program SEER*Stat Database: Incidence—SEER 18 Regs Research Data ? Hurricane Katrina Impacted Louisiana Cases, Nov 2013 Sub (1973–2011 varying)—Linked To County Attributes—Total U.S., 1969–2012 Counties, National Cancer Institute, DCCPS, Surveillance Research Program, Surveillance Systems Branch, released April 2014 (updated 5/7/2014), based on the November 2013 submission. www.seer.cancer.gov 10. Halberg F, Lagoguey M, Reinberg A (1983) Human circannual rhythms over a broad spectrum of physiological processes. Int J Chronobiol 8(4):225–268 11. Leppaluoto J, Sikkila K, Hassi J (1998) Seasonal variation of serum TSH and thyroid hormones in males living in subarctic environmental conditions. Int J Circumpolar Health 57(Suppl 1):383–385 12. Sothern RB, Smaaland R, Moore JG (1995) Circannual rhythm in DNA synthesis (S-phase) in healthy human bone marrow and rectal mucosa. FASEB J 9(5):397–403 13. Haus E, Lakatua DJ, Sackett-Lundeen L (1997) Circannual variation of cell proliferation in lymphoid organs and bone marrow of BDF1 male mice on three lighting regimens. Chronobiol Int 14(4):347–362 14. Pace WD, Dickinson LM, Staton EW (2004) Seasonal variation in diagnoses and visits to family physicians. Ann Fam Med 2(5):411–417 15. Walter SD, Elwood JM (1975) A test for seasonality of events with a variable population at risk. Br J Prev Soc Med 29(1):18–21
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