Adolescent non-gynae cancer survivors may have increased infertility risk
Adolescent and young adult female survivors of certain non-gynaecological cancers may have an elevated risk of infertility with parity playing a role in this risk, according to a study from Canada.
“Young female survivors of certain cancers are at higher risk of being diagnosed with infertility as compared with age-matched cohorts,” said study author Assistant Professor Maria Velez from the Department of Obstetrics and Gynaecology at Queen’s University in Kingston, Ontario, Canada, who presented the findings at ESHRE 2018.
“Parity previous to cancer modifies this effect with nulliparous women being more likely to be diagnosed with infertility compared with women with previous pregnancies,” she said.
Using data obtained from healthcare databases in Ontario, Canada, researchers conducted a population-based cohort study, identifying 15,107 women aged 15–39 years who were survivors (≥5 years recurrence-free) of breast, brain, head or neck, thyroid, colorectal, urological, or haematological cancers, or melanoma diagnosed between 1992 and 2011 (mean age at diagnosis 31.2 years) and comparing them with 64,314 age-, parity-, and census subdivision-matched cancer-free women (unexposed group). Survivors and controls were followed up for a median 13.9 and 14.3 years, respectively.
Women with a history of infertility, tubal ligation, hysterectomy, or oophorectomy prior to cancer diagnosis were excluded.
Overall, cancer survivors were more likely to be diagnosed with infertility than their unexposed counterparts (12.0 percent vs 9.4 percent; p<0.001), with a mean age of 34.5 and 34.9 years at infertility diagnosis among survivors and unexposed women, respectively. [ESHRE 2018, abstract O-018]
However, the risk of infertility diagnosis varied by cancer type and parity. Compared with women without cancer, the risk of infertility was higher among survivors of breast cancer (adjusted relative risk [adjRR], 1.38, 95 percent confidence interval [CI], 1.23–1.55), haematological cancers (adjRR, 1.42, 95 percent CI, 1.28–1.59), and thyroid cancer (adjRR, 1.17, 95 percent CI, 1.08–1.27; p<0.001 for all), with a trend towards a higher risk of infertility in melanoma survivors (adjRR, 1.13, 95 percent CI, 0.99–1.30; p=0.07). Conversely, survivors of brain (adjRR, 1.17; p=0.25), head or neck (adjRR, 0.94; p=0.72), or colorectal cancer (adjRR, 1.11; p=0.60) did not have a higher risk of infertility compared with women without cancer.
The higher risk of infertility among breast and haematological cancer survivors was only elevated in nulliparous women (adjRR, 1.52 and adjRR, 1.47, respectively; p<0.001 for both), with the association no longer evident in parous women (adjRR, 1.03; p=0.84 and adjRR, 1.18; p=0.35, respectively). Similarly, the elevated risk of infertility in melanoma and urological cancer survivors was only observed in nulliparous women (adjRR, 1.16; p=0.05 and adjRR, 1.50; p=0.04, respectively). In contrast, the higher risk of infertility in thyroid cancer survivors compared with women without cancer was present regardless of parity (adjRR, 1.32 and adjRR, 1.15 in parous and nulliparous women, respectively; p=0.003 for both).
“Our finding of a potential effect of thyroid cancer that we know is subject to overdiagnosis, and melanoma needs to be further studied, and if we confirm any effect, [we need to] try to understand the mechanisms,” said Velez.
According to Velez, the database may not have captured the non-biological reasons for which women seek out treatment for infertility which posed a potential limitation. Furthermore, the researchers did not factor in cancer stage or treatment in this analysis.
“Many cancer therapies are gonadotoxic, increasing the risk of infertility and premature ovarian insufficiency,” said Velez. “Reproductive health surveillance in female adolescents and young adults with cancer is a priority, especially for women with breast and haematological cancer diagnoses,” she said.