Reproductive Results in Cancer Survivors after Fertility Sparing Management: The Need for the Standardization of Definitions

SIMPLE SUMMARY: The assessment of oncological outcomes has been well defined by overall survival and its surrogates: disease-free/progression-free survival. Although fertility-sparing management (FSM) is used in clinical practice, definitions of reproductive outcomes have not been established. Currently, various definitions are used, and different criteria for the same terms are applied. The aim of this narrative review is to show the diversity in the ways that reproductive outcomes after FSM are reported. It is unknown whether pregnancy or childbirth rates should be the primary endpoints, and the assessment of pregnancy/birth rates is confusing due to the selection of different reference groups. Additional bias is related to “seeking pregnancy” patients, who are distinguished with no clear criteria and are used as a denominator. Moreover, the discussion with patients about the chances of childbearing is complicated. FSM in young women has an unquestionably important role, but uniform definitions of reproductive outcomes should be established. ABSTRACT: In fertility-sparing management (FSM), two different issues can be distinguished: the risk of recurrence/death and the chance of childbearing. Survival is the principal outcome in oncology, and definitions of overall survival and progression-free survival are therefore well defined and widely accepted. The introduction of FSM to clinical practice was determined by the desire of young cancer patients to still have children. Initially, in small groups of patients, any pregnancy and/or childbirth were considered successes. Nowadays, FSM occupies an important place in cancer treatment, with thousands of young women treated successfully. However, in contrast to survival, no definition has been established for evaluating the reproductive outcomes of FSM. This review article evaluates the current pregnancy and birth rates of cancer patients. Differences between fertility-sparing and conservative treatment are analyzed, and improper and confusing interchangeable applications of these terms are pointed out. Additionally, various reasons for choosing FSM as a treatment method—which are not directly related to fertility preservation (treatment mismatch)—are presented. Uniform definitions of reproduction after FSM should be established to enable the comparison of results and facilitate the counseling of patients regarding the chances of reproduction.