Risk of testicular germ-cell tumours in relation to childhood physical activity

Abstract

The US Servicemen's Testicular Tumor Environmental and Endocrine Determinants (STEED) case -control study of testicular germcell tumours (TGCTs) enrolled participants and their mothers in 2002 -2005. Hours of sports or vigorous childhood physical activity per week were ascertained for three time periods; 1st -5th grades, 6th -8th grades and 9th -12th grades. Son-and mother-reports were analysed separately and included 539 control son -mother pairs and 499 case son -mother pairs. Odds ratios and 95% confidence intervals were produced. The analysis of the sons' responses found no relationship between childhood physical activity and TGCT, while the mothers' analysis found an inverse association, which was solely due to nonseminoma. Future studies should seek to validate responses further using recorded information sources such as school records. Despite testicular germ-cell tumours (TGCTs) being the commonest malignancy in men aged 15 -34 years of European ancestry (IARC, 2002;McGlynn et al, 2003), cryptorchidism, prior and family history of TGCT are the only consistently reported risk factors (McGlynn, 2001). Exposures early in life are thought to be integral in the initial stages of the disease process and in the 60% observed increased incidence between 1977 and 1997(Purdue et al, 2005. Carcinoma in situ precedes TGCT and is postulated to arise from primordial germ cells (Skakkebaek et al, 1987), which may imply that in utero exposures are important (Moller, 1993). However, later exposures are still likely to influence risk, as has been indicated by the finding of a period effect in an analysis of incidence trends (Moller, 2001).Increased levels of childhood physical activity have been reported to be protective against certain malignancies (Thune and Furberg, 2001). The US Servicemen's Testicular Tumor Environmental and Endocrine Determinants (STEED) Study was used to investigate whether childhood physical activity was associated with risk of TGCT and its two histologic subtypes of seminoma and nonseminoma. (McGlynn et al, 2007). Briefly, between April 2002 and January 2005 participants aged 18 -45 years with at least one serum sample stored in the Department of Defense Serum Repository (DoDSR, Silver Spring, MD, USA) were eligible for enrollment. Diagnoses of TGCT were limited to classic seminoma or nonseminoma (embryonal carcinoma, yolk sac carcinoma, choriocarcinoma, teratomas, mixed germ-cell tumour). The study was designed as a pair-matched, case -control study. Age (within 1 year), race (White, Black, other) and date of available serum sample (within 30 days) were the variables used for matching. In total, 767 cases and 928 controls were recruited, of which there were 720 matched case -control pairs. Permission was given by 1247 participants to contact their mothers. Forty-three mothers were found to be ineligible, 28 had their status pending and 16 could not be located. Of the 1160 eligible mothers contacted, 72 refused, giving a participation rate of 94%. Both members of a mother -son pair had to provid...

Physical Activity and Genitourinary Cancer Prevention

“…3.5). Four studies (Cook et al 2008;Dosemeci et al 1993;Littman et al 2009;Srivastava and Kreiger 2000) reported a null association and two studies found a statistically nonsignificant positive relation between physical activity and testicular cancer (Paffenbarger et al 1987;Thune and Lund 1994). One study noted a statistically nonsignificant inverse association between time spent sitting and testicular cancer (Dosemeci et al 1993).…”

“…Testicular Cancer Study Group 1994) of the nine studies (Brownson et al 1991;Cook et al 2008;Dosemeci et al 1993;Gallagher et al 1995;Littman et al 2009;Paffenbarger et al 1987;Srivastava and Kreiger 2000;Thune and Lund, 1994;U.K. Testicular Cancer Study Group 1994) that examined physical activity in relation to testicular cancer observed a statistically inverse association between a measure of physical activity and testicular cancer (Fig.…”

“…Testicular Cancer Study Group 1994). One study that was classified as a null study because of the lack of an association with vigorous activity noted a borderline statistically significant positive trend of the relation of moderate activity to testicular cancer (Cook et al 2008). No study reported a statistically significant positive trend between physical activity and testicular cancer.…”

“…That study reported strong positive relations of cycling and horseback-riding to testicular cancer, with relative risk estimates ranging from a 99% to 356% increased testicular cancer risk, but did not present additional data regarding recreational physical activity and was not further considered in the present chapter. Thus, a total of nine studies remained for review here (Brownson et al 1991;Cook et al 2008;Dosemeci et al 1993;Gallagher et al 1995;Littman et al 2009;Paffenbarger et al 1987;Srivastava and Kreiger 2000;Thune and Lund, 1994; U.K. Testicular Cancer Study Group).…”

“…Ten epidemiologic investigations examined the relation of physical activity to testicular cancer, including two cohort studies (Paffenbarger et al 1987;Thune and Lund 1994) and eight casecontrol studies (Brownson et al 1991;Coldman et al 1982;Cook et al 2008;Dosemeci et al 1993;Gallagher et al 1995;Littman et al 2009;Srivastava and Kreiger 2000;U.K. Testicular Cancer Study Group 1994).…”