Ovarian cancer
We found one retrospective cohort study and one case–control study regarding the association of fertility treatments and ovarian cancer risk in BRCA1/2 mutation carriers to include in our review (Table 1).
Table 1 Fertility treatments and risk of ovarian cancer in BRCA mutation carriers Perri et al. conducted a cohort study with Jewish Israeli women undergoing genetic counseling because of family history of ovarian cancer [11]. They included a total of 718 BRCA1 and 331 BRCA2 mutation carriers. 139 of the BRCA1 and 33 of the BRCA2 mutation carriers were diagnosed with ovarian cancer. Furthermore, three healthy BRCA1+2 mutation carriers and three carriers of unknown mutations with ovarian cancer as well as 18 carriers of unknown mutations without ovarian cancer were included. Among the included women, 164 reported undergoing fertility treatments. Among those were 105 BRCA1, 54 BRCA2 and one BRCA1+2 mutation carriers and four patients with unknown mutations. The treatments included medications containing clomiphene citrate (CC) or gonadotropins (GN) in 82 and 69 of the participants, respectively. Three patients in the CC and one in the GN group were diagnosed with ovarian cancer. 66 participants reported in vitro fertilization (IVF) and 50 received a combination of those treatments. 4 of the IVF and 10 of the mixed treatment group had ovarian cancer, respectively. The mean age of the women included was 47.1 years in the group with and 50.4 years in the group without fertility treatment. The patients with ovarian cancer had a mean age of 53.6 and the patients without ovarian cancer of 49.1 years. 13.4% of the group with and 10.1% of the group without fertility treatment had undergone prophylactic bilateral salpingo-oophorectomy (PBSO) at a mean age of 44.7 and 46.9 years in the group with and without fertility treatment, respectively. In the multivariate age-adjusted analysis, the study found no association between ovarian cancer and fertility treatments for BRCA1 (OR = 0.81; 95% CI 0.43–1.53) and BRCA2 mutation carriers (OR = 1.01; 95% CI 0.31–3.30). No association was found also after adjustment for the different fertility treatments, i.e., CC, GN, and IVF. Dosage, number, and duration of the different treatments were not investigated, and information on the cause of infertility was not given.
Gronwald et al. included 791 BRCA1 and 150 BRCA2 case–control pairs in their study. In total, 11 participants had undergone IVF and 9 intrauterine insemination (IUI) [12]. 34 had been treated with selective estrogen receptor modulators (SERM), two with gonadotropins (GN) and 8 with other fertility medications. Among the ovarian cancer cases, 4 had undergone IVF and IUI each. 12 of the ovarian cancer patients had used SERM, two GN and 4 other fertility medication. The mean age was 64 and 63 years for cases and controls. The study found no association between ovarian cancer and IVF treatment (OR = 0.66; 95% CI 0.18–2.33, p = 0.52) or IUI (OR = 0.83; 95% CI 0.22–3.13, p = 0.79) in BRCA mutation carriers, although the confidence intervals were wide. Likewise, no association was found between ovarian cancer and the use of fertility medication. ORs were 0.55 (95% CI 0.27–1.10, p = 0.09) for SERM, 1.35 (95% CI 0.11–16.62, p = 0.82) for GN and 1.00 (95% CI 0.25–4.00, p = 1.0) for other medication. Separate analyses for BRCA1 and BRCA2 carriers were not provided. Dosage, number, and duration of the different treatments were not examined and the cause of infertility was not provided.
Breast cancer
We found one case–control study on the association between fertility treatment and breast cancer risk in BRCA mutation carriers and one prospective cohort study on the long-term safety of medication used for fertility preservation in women already diagnosed with breast cancer (Table 2).
Table 2 Fertility treatments and risk of breast cancer in BRCA mutation carriers Kotsopoulos et al. conducted a matched case–control study that included 1054 pairs of BRCA1 and 326 pairs of BRCA2 mutation carriers [13]. In total, 9 of the cases and 11 of the controls had undergone IVF. 61 of the cases and 56 of the controls reported ever use of fertility medication. Among those, 44% (24 cases and 27 controls) had used medication-containing clomiphene citrate (CC), 22% (16 cases and 10 controls) medication-containing gonadotropins (GN), and 8% other fertility medication, such as bromocriptine, a combination of various drugs or estrogen. For 26%, further information on the fertility medication was missing. The mean age was 46.0 years for cases and 46.2 years for controls. Women who had undergone bilateral mastectomy were excluded. The study did not find an association between the risk of breast cancer and IVF treatment (OR = 0.98; 95% CI = 0.39–2.45) in BRCA1/2 mutation carriers. No association was found when adjusted for BRCA1 (OR = 0.99; 95% CI 0.35–2.76) and BRCA2 (OR = 0.88; 95% CI 0.12–6.52) mutation. Likewise, the study did not find an increase in risk associated with the use of fertility medication (OR = 1.21; 95% CI = 0.81–1.82) in BRCA1/2 mutation carriers. The results were similar for BRCA1 (OR = 1.22; 95% CI 0.76–1.94) and BRCA2 (OR = 1.25; 95% CI 0.56–2.78) mutation carriers. These results were not significantly affected by stratification for parity. When adjusted for the type of fertility medication, the study found no association between breast cancer risk and medication-containing clomiphene citrate (OR = 0.96; 95% CI 0.54–1.72, p = 0.89) in BRCA1/2 mutation carriers. A possible adverse effect was observed for GN containing fertility medication (OR = 2.32; 95% CI 0.91–5.95, p = 0.08). However, only few women were exposed and the effect was not statistically relevant. Dosage, number, and duration of the different treatments as well were not provided and possible effects of different causes of infertility were not examined.
Kim et al. included 337 breast cancer patients in a prospective cohort study to investigate the safety of letrozole and gonadotropin stimulation for fertility preservation (FP) [14]. 120 women underwent FP before chemotherapy, the rest served as control group. In total, the study included 28 BRCA1, 18 BRCA2 carriers and one carrier of both a mutation in BRCA1 and BRCA2. 26 of the mutation carriers underwent FP. The mean gonadotropin dose for ovarian stimulation was 2511.0 ± 1557.0 IU. The mean follow-up after diagnosis was 5 years in the FP group and 6.9 years for controls. The study did not find a difference in the relapse-free or overall survival between the FP and the control group using the Kaplan–Meier method (p = 0.57). Also, tumor size, grading, involvement of lymph nodes, hormone receptor status and HER-2/neu overexpression were examined. No significant effect was found for these variables when FP and control group were compared. Molecular testing was not available for all participants and numbers were low. Information on risk-reducing salpingo-oophorectomy during follow-up was not collected and separate analyses for BRCA1 and BRCA2 mutation carriers were not provided.