Summary Background The effect of many contemporary chemotherapeutic drugs on pregnancy and livebirth is not well established. We aimed to establish the effects of these drugs on pregnancy in male and female survivors of childhood cancer not exposed to pelvic or cranial radiotherapy. Methods We used data from a subset of the Childhood Cancer Survivor Study cohort, which followed 5-year survivors of the most common types of childhood cancer who were diagnosed before age 21 years and treated at 27 institutions in the USA and Canada between 1970 and 1999. We extracted doses of 14 alkylating and similar DNA interstrand crosslinking drugs from medical records. We used sex-specific Cox models to establish the independent effects of each drug and the cumulative cyclophosphamide equivalent dose of all drugs in relation to pregnancies and livebirths occurring between ages 15 years and 44 years. We included siblings of survivors as a comparison group. Findings We included 10 938 survivors and 3949 siblings. After a median follow-up of 8 years (IQR 4–12) from cohort entry or at age 15 years, whichever was later, 4149 (38%) survivors reported having or siring a pregnancy, of whom 3453 (83%) individuals reported at least one livebirth. After a median follow-up of 10 years (IQR 6–15), 2445 (62%) siblings reported having or siring a pregnancy, of whom 2201 (90%) individuals reported at least one livebirth. In multivariable analysis, survivors had a decreased likelihood of siring or having a pregnancy versus siblings (male survivors: hazard ratio [HR] 0·63, 95% CI 0·58–0·68; p<0·0001; female survivors: 0·87, 0·81–0·94; p<0·0001) or of having a livebirth (male survivors: 0·63, 0·58–0·69; p<0·0001; female survivors: 0·82, 0·76–0·89; p<0·0001). In male survivors, reduced likelihood of pregnancy was associated with upper tertile doses of cyclophosphamide (HR 0·60, 95% CI 0·51–0·71; p<0·0001), ifosfamide (0·42, 0·23–0·79; p=0·0069), procarbazine (0·30, 0·20–0·46; p<0·0001) and cisplatin (0·56, 0·39–0·82; p=0·0023). Cyclophosphamide equivalent dose in male survivors was significantly associated with a decreased likelihood of siring a pregnancy (per 5000 mg/m2 increments: HR 0·82, 95% CI 0·79–0·86; p<0·0001). However, in female survivors, only busulfan (<450 mg/m2 HR 0·22, 95% CI 0·06–0·79; p=0·020; ≥450 mg/m2 0·14, 0·03–0·55; p=0·0051) and doses of lomustine equal to or greater than 411 mg/m2 (0·41, 0·17–0·98; p=0·046) were significantly associated with reduced pregnancy; cyclophosphamide equivalent dose was associated with risk only at the highest doses in analyses categorised by quartile (upper quartile vs no exposure: HR 0·85, 95% CI 0·74–0·98; p=0·023). Results for livebirth were similar to those for pregnancy. Interpretation Greater doses of contemporary alkylating drugs and cisplatin were associated with a decreased likelihood of siring a pregnancy in male survivors of childhood cancer. However, our findings should provide reassurance to most female survivors treated with chemotherapy without radiotherapy to the pelvis or...

Survivors of childhood sarcomas and those who received chest radiation therapy are at risk for secondary breast cancer. When assessing a survivor's risk, clinicians should consider primary diagnosis, previous radiation therapy, family cancer history, and history of thyroid disease.

A B S T R A C T PurposeThe purpose of this study was to quantify the risk of breast cancer in relation to radiation dose and chemotherapy among survivors of childhood cancer. MethodsWe conducted a case-control study of breast cancer in a cohort of 6,647 women who were 5-year survivors of childhood cancer and who were treated during 1970 through 1986. One hundred twenty patients with histologically confirmed breast cancer were identified and were individually matched to four selected controls on age at initial cancer and time since initial cancer. Medical physicists estimated radiation dose to the breast tumor site and ovaries on the basis of medical records. ResultsThe odds ratio for breast cancer increased linearly with radiation dose, and it reached 11-fold for local breast doses of approximately 40 Gy relative to no radiation (P for trend Ͻ .0001). Risk associated with breast irradiation was sharply reduced among women who received 5 Gy or more to the ovaries (P ϭ .002). The excess odds ratio per Gy was 0.36 for those who received ovarian doses less than 5 Gy and was 0.06 for those who received higher doses. Radiation-related risk did not vary significantly by age at exposure. Borderline significantly elevated risks were seen for doxorubicin, dactinomycin, dacarbazine, and carmustine. ConclusionResults confirm the radiation sensitivity of the breast in girls age 10 to 20 years but do not demonstrate a strong effect of age at exposure within this range. Irradiation of the ovaries at doses greater than 5 Gy seems to lessen the carcinogenic effects of breast irradiation, most likely by reducing exposure of radiation-damaged breast cells to stimulating effects of ovarian hormones.