Risk factors for testicular cancer – differences between pure non‐seminoma and mixed seminoma/non‐seminoma?

Abstract

The origin of testicular germ cell cancer (TGCC) is believed to be carcinoma in situ cells developed in utero. Clinically, TGCCs are divided into two major histological groups, seminomas and non-seminomas, where the latter group includes non-seminomatous TGCCs with seminomatous components (mixed S/NS TGCC). Recent studies, however, have suggested that non-seminomas and mixed S/NS TGCCs could have certain differences in aetiology, and in this study the TGCCs were divided into three, rather than the conventional two histological groups. A large case-control study was undertaken on data on all live-born boys registered in the Medical Birth Registry of Norway during the period 1967-1998 (n=961 396). Among these were 1087 TGCC cases registered in the Cancer Registry of Norway until February 2004. We found several risk factors for TGCC, including low parity, low gestational age, epilepsy and retained placenta. Several of the variables studied seemed to be risk factors for specific histological groups, e.g. parity 0 vs. 2 and low gestational age being associated with increased risk of non-seminomas, but not of mixed S/NS TGCC, and low maternal age being associated with increased risk of mixed S/NS TGCC, but not of non-seminomatous TGCC. Therefore, our results might suggest that non-seminomas and mixed S/NS TGCCs have partially different risk factors, whose associations may be obscured by combining these two histological groups. The histological groups were not significantly different, however. Most of our findings on risk factors for TGCC are in agreement with at least some previous studies. An unexplainable exception is low birth weight being associated with reduced risk of TGCC in our study.

Birth weight and the risk of testicular cancer: A meta‐analysis

“…Nine of the 13 studies included in the meta-analysis on the association of low birth weight with testicular cancer risk suggested a positive association, [11][12][13]15,17,33,34,37,38 although the association was statistically significant in only 4 of them. [11][12][13]15 In 2 studies no association was found 16,35 and in 2 others an inverse association was observed 32,36 which was statistically significant in 1 study. 32 There was an overall statistically significant association between low birth weight and higher risk for testicular cancer (OR 5 1.18, 95% CI: 1.01-1.38), although effect estimates were heterogeneous across reviewed studies (p for heterogeneity 5 0.005, I…”

“…12,13,[15][16][17]33,36 Three of the studies did not give data for the high birth weight stratum and were not included in the relevant analysis. 15,16,35 Low birth weight and testicular cancer Figure 2 presents the forest plot for all included studies and the summary estimate across them. Nine of the 13 studies included in the meta-analysis on the association of low birth weight with testicular cancer risk suggested a positive association, [11][12][13]15,17,33,34,37,38 although the association was statistically significant in only 4 of them.…”

“…The cases in these studies were born between 1920 and 1998 and were found from cancer registries, except 2 13,36 that used hospital records. The source for birth weight was birth registries 11,31,32,34,35,38 or interviews and questionnaires. 12,13,[15][16][17]33,36 Three of the studies did not give data for the high birth weight stratum and were not included in the relevant analysis.…”

Subtype-Specific Risk of Testicular Tumors among Immigrants and Their Descendants in Sweden, 1960 to 2007

“…Possibly, the two types do not entirely share risk factors, as suggested by some previous studies (34)(35)(36)(37). However, collective evidence from the descriptive literature and marked inconsistencies between analytic studies distinguishing seminomas from nonseminomas indicate that either they are etiological rather than homogeneous, or some heterogeneity exists but the dichotomization is etiologically irrelevant.…”

Er det forskningsmessig interessant å koble data fra Medisinsk fødselsregister med data fra Kreftregisteret?

“…Forhøyet risiko ble også funnet etter svangerskap med placentainsufficiens og retinert placenta. De samme variablene er senere studert i en oppdatert og utvidet MFR-kohort av Aschim og medarbeidere i 2006 (8). Denne studien baserte seg på fire ganger så mange testikkelkrefttilfeller, og mesteparten av funnene er i samsvar med hva som ble funnet i det første arbeidet.…”