Reproductive and sexual sequelae of neuroendocrine tumour therapies: an under-recognised challenge

Neuroendocrine tumours (NETs) are heterogeneous, biologically variable tumours arising from the diffuse neuroendocrine system. While more frequently seen in older patients, the incidence and prevalence of NETs in the younger population are increasing. In addition, because of their generally slow progression and favourable prognosis, coupled with widely available effective treatments, survival times even with metastatic tumours may often be prolonged. However, there is a paucity of data on the effect of treatment of NETs on men's and women's reproductive and sexual health. In this review, we have evaluated the effects of NET therapies, including somatostatin analogues (SSTAs), molecular targeted therapy (everolimus and sunitinib), peptide receptor radionuclide therapy (PRRT), and chemotherapy, on reproductive and sexual function in patients with NETs. There is a lack of evidence on the detrimental effects of SSTAs on human fertility, and indeed, many patients have conceived successfully after many years of treatment with SSTAs. Even patients who have received SSTAs during pregnancy have generally shown positive maternal and fetal outcomes. While the effects of PRRT and molecular targeted therapy on fertility are as yet poorly defined, chemotherapy has a proven negative impact on fertility; thus, family and pregnancy planning are strongly recommended before the initiation of chemotherapy. Finally, data on the effects of NET treatment on sexual function are very limited; however, neuroendocrine tumours can express oestrogen receptors/progesterone receptors (ER/PR) or testosterone receptors (TR); thus, checking tumour tissue for ER/PR/TR status prior to considering hormonal therapy for sexual dysfunction should be considered but warrants additional studies.