Cancer and pregnancy: in depth analysis of an international registry with focus on breast cancer.
The decision to start cytotoxic treatment when cancer is diagnosed during pregnancy strikes a delicate balance between maternal well-being and fetal safety. Recently, we reported on the first prospective follow-up study of children with antenatal exposure to cancer treatment and provided proof of concept that the fetal risk can be considered to be overall reassuring. This study opened the perspective to developing standard treatments for pregnancy-associated cancers. However, working towards this goal now raises new questions that need addressing in large-scale and case-controlled studies. First, the true epidemiology and prognosis of pregnancy-associated cancers is incompletely understood. Second, the question rises whether he diagnostic and therapeutic approach, which is currently based on the standard treatment in non-pregnant patients, is both safe and effective for the outcome of the pregnancy and the cancer. The objective of this project is to use an international registry of patients with cancer during and outside pregnancy to 1) characterize the exact burden of cancer in pregnancy today, and 2) investigate specific concerns that have risen in the diagnosis and treatment of pregnancy-associated breast cancer, the most frequent of all pregnancy-associated cancers. The registry represents a unique research instrument that will allow for studies that are sufficiently large-scaled to document reliable information on the common and uncommon types of cancer in pregnancy..