Abstract
BACKGROUND: Increasing evidence shows that some cancers originate in utero. It is hypothesized that elevated exposure to some steroid hormones might increase cancer risk, and that hormone transfer between twin fetuses could result in different prenatal exposure to testosterone.
METHODS: This large-scale prospective twin study compared opposite-sex (OS) and same-sex (SS) twins to test the impact of intrauterine exposures on cancer risk. Based on the Danish and Swedish twin and cancer registries, we calculated incidence rate ratios for OS and SS twins while standardized incidence ratios (SIRs) with 95% confidence intervals (CIs) were calculated for OS/SS twins compared with the general population.
RESULTS: A total of 18,001 cancers were identified during 1943-2009. No significant differences were observed between OS and SS twins, neither for the sex-specific cancers nor for cancer at all sites. All-cause cancer was slightly reduced for OS and SS twins compared with the general population, significant for OS males (SIR = 0.95; 95% CI 0.92-0.98) and for SS males and females (SIR = 0.97; 95% CI 0.94-0.99).
CONCLUSIONS: Our data suggest that having a male co-twin - which may entail higher exposure to prenatal testosterone - does not increase the risk of sex-specific cancers in OS females. Furthermore, the study supports that twinning per se is not a risk factor of cancer.
IMPACT: Findings are reassuring as they fail to provide evidence for the hypothesis that endocrine or other difference in the in utero milieu affects the risk of sex-specific cancers.
| Original language | English |
|---|---|
| Journal | Cancer Epidemiology, Biomarkers & Prevention |
| Volume | 24 |
| Issue number | 10 |
| Pages (from-to) | 1622-8 |
| ISSN | 1055-9965 |
| DOIs | |
| Publication status | Published - Oct 2015 |
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Risk of sex-specific cancers in opposite-sex and same-sex twins in Denmark and Sweden. / Ahrenfeldt, Linda Juel; Skytthe, Axel; Möller, Sören; Czene, Kamila; Adami, Hans-Olov; Mucci, Lorelei A; Kaprio, Jaakko; Petersen, Inge; Christensen, Kaare; Lindahl-Jacobsen, Rune.
In: Cancer Epidemiology, Biomarkers & Prevention, Vol. 24, No. 10, 10.2015, p. 1622-8.Research output: Contribution to journal › Journal article › Research › peer-review
TY - JOUR
T1 - Risk of sex-specific cancers in opposite-sex and same-sex twins in Denmark and Sweden
AU - Ahrenfeldt, Linda Juel
AU - Skytthe, Axel
AU - Möller, Sören
AU - Czene, Kamila
AU - Adami, Hans-Olov
AU - Mucci, Lorelei A
AU - Kaprio, Jaakko
AU - Petersen, Inge
AU - Christensen, Kaare
AU - Lindahl-Jacobsen, Rune
N1 - Copyright © 2015, American Association for Cancer Research.
PY - 2015/10
Y1 - 2015/10
N2 - BACKGROUND: Increasing evidence shows that some cancers originate in utero. It is hypothesized that elevated exposure to some steroid hormones might increase cancer risk, and that hormone transfer between twin fetuses could result in different prenatal exposure to testosterone.METHODS: This large-scale prospective twin study compared opposite-sex (OS) and same-sex (SS) twins to test the impact of intrauterine exposures on cancer risk. Based on the Danish and Swedish twin and cancer registries, we calculated incidence rate ratios for OS and SS twins while standardized incidence ratios (SIRs) with 95% confidence intervals (CIs) were calculated for OS/SS twins compared with the general population.RESULTS: A total of 18,001 cancers were identified during 1943-2009. No significant differences were observed between OS and SS twins, neither for the sex-specific cancers nor for cancer at all sites. All-cause cancer was slightly reduced for OS and SS twins compared with the general population, significant for OS males (SIR = 0.95; 95% CI 0.92-0.98) and for SS males and females (SIR = 0.97; 95% CI 0.94-0.99).CONCLUSIONS: Our data suggest that having a male co-twin - which may entail higher exposure to prenatal testosterone - does not increase the risk of sex-specific cancers in OS females. Furthermore, the study supports that twinning per se is not a risk factor of cancer.IMPACT: Findings are reassuring as they fail to provide evidence for the hypothesis that endocrine or other difference in the in utero milieu affects the risk of sex-specific cancers.
AB - BACKGROUND: Increasing evidence shows that some cancers originate in utero. It is hypothesized that elevated exposure to some steroid hormones might increase cancer risk, and that hormone transfer between twin fetuses could result in different prenatal exposure to testosterone.METHODS: This large-scale prospective twin study compared opposite-sex (OS) and same-sex (SS) twins to test the impact of intrauterine exposures on cancer risk. Based on the Danish and Swedish twin and cancer registries, we calculated incidence rate ratios for OS and SS twins while standardized incidence ratios (SIRs) with 95% confidence intervals (CIs) were calculated for OS/SS twins compared with the general population.RESULTS: A total of 18,001 cancers were identified during 1943-2009. No significant differences were observed between OS and SS twins, neither for the sex-specific cancers nor for cancer at all sites. All-cause cancer was slightly reduced for OS and SS twins compared with the general population, significant for OS males (SIR = 0.95; 95% CI 0.92-0.98) and for SS males and females (SIR = 0.97; 95% CI 0.94-0.99).CONCLUSIONS: Our data suggest that having a male co-twin - which may entail higher exposure to prenatal testosterone - does not increase the risk of sex-specific cancers in OS females. Furthermore, the study supports that twinning per se is not a risk factor of cancer.IMPACT: Findings are reassuring as they fail to provide evidence for the hypothesis that endocrine or other difference in the in utero milieu affects the risk of sex-specific cancers.
KW - Cancer
KW - in utero exposure
KW - testosterone
KW - hormones
KW - twins
U2 - 10.1158/1055-9965.EPI-15-0317
DO - 10.1158/1055-9965.EPI-15-0317
M3 - Journal article
VL - 24
SP - 1622
EP - 1628
JO - Cancer Epidemiology, Biomarkers & Prevention
JF - Cancer Epidemiology, Biomarkers & Prevention
SN - 1055-9965
IS - 10
ER -