Chemotherapy is known to have a negative impact on the reproductive potential of young breast cancer patients. Its effects on women’s post-treatment fertility, however, are still poorly understood. A study to be presented at the ESMO 2018 Congress in Munich, has confirmed that natural pregnancies are possible after chemotherapy but that survivors’ desire to have children decreases greatly after treatment, calling into question the need for systematic recourse to fertility preservation measures.

Fertility preservation today is based on harvesting and freezing eggs or embryos after in vitro fertilisation. It is commonly offered to breast cancer patients under 40 during the first consultations following diagnosis. Globally, women in this age group represent less than 7% of breast cancer diagnoses, and survivors have a 70% lower chance of pregnancy compared with the general population.

According to study author, Dr. Jérôme Martin-Babau from Centre Armoricain de Radiothérapie, Imagerie Médicale et Oncologie in Plérin, France, “the main barrier to accessing fertility preservation measures for patients in France is that it requires lab facilities and medical expertise that are only available at larger hospitals. Women may have to travel further than their usual cancer centre for the procedure.”

The French National Cancer Plan prioritises this solution as a key service to be rolled out nationwide. “We wanted to find out whether the need and demand for it among breast cancer survivors was on a par with the level of investment and organisation called for by the policymakers,” Martin-Babau continued.

In the course of the study, 96 eligible patients aged between 18 and 40 years and treated by chemotherapy for non-metastatic breast cancer were identified – 60 agreed to participate in the survey. “We based our questionnaire on existing tools found in the literature and added a dedicated section on the changes in patients’ menstrual cycles,” Martin-Babau reported.

Participants’ median age at diagnosis was 36 years, and the median time between the end of their chemotherapy and participation in the study was 57 months. In over half of cases, the cancer had spread to the lymph nodes at the time of diagnosis, which means it had a higher risk of recurrence. Triple negative tumours were diagnosed in 10 women: their prognosis is worsened by the fact that they cannot receive the anti-hormonal treatment usually prescribed after chemotherapy. All patients, however, were in complete remission by the time of the survey.

The results showed that 83% of participants experienced amenorrhea – a complete absence of menstruation – during their treatment with chemotherapy. “This was an expected finding,” said Martin-Babau. “What we didn’t expect was that 86% of these patients also reported their menstrual cycle returning to normal within the following year after the end of chemo – an indication that the treatment had not completely damaged their ovaries.”

The evolution of patients’ desire to bear children over the course of the disease was also assessed: more than one third of women reported having had plans to become pregnant before beginning treatment. By contrast, only one in ten stated that they still had this wish after the end of their chemotherapy.

“Of the six patients who did still want to have children, four women actually managed to get pregnant, although two eventually miscarried,” Martin-Babau reported. The assumption that it is difficult to achieve pregnancy naturally after breast cancer was thus belied in this patient cohort.

“Of course, our study was limited to one centre and reflects the activity of just a few doctors – the reality may be quite different elsewhere. In addition, one third of patients we identified didn’t respond to the survey, possibly due to frustration with their personal situation. Their participation may have changed our results,” Martin-Babau cautioned.

Drawing conclusions from the findings, he observed: “The fact is that most forms of breast cancer are stimulated by hormones. The implantation of in vitro produced embryos requires women to take additional hormones that could potentially play a role in disease recurrence – we currently have limited data to alleviate this concern.”

“In a context, then, where it turns out that natural pregnancies are still possible after treatment, and where the actual demand for fertility preservation measures seems to be relatively low, we as clinicians need to think about how to provide the most balanced information possible during the onco-fertility counselling of these young patients,” he said.

Commenting on the study for ESMO, Dr. Matteo Lambertini, ESMO fellow at the Institut Jules Bordet in Brussels, Belgium, said: “ Previous data have shown that only a small proportion of women actually choose to undergo fertility preservation measures at the time of breast cancer diagnosis.

The present findings, though based on a small patient cohort, additionally tell us that breast cancer survivors’ desire to have children decreases by the time they finish treatment, while simultaneously confirming that natural pregnancies are still possible after chemotherapy. However, this does not mean that oncologists shouldn’t talk about fertility preservation measures with their patients, including in cases where their cancer centre doesn’t offer fertility services onsite: indeed, the minority of women who are interested will gladly travel to the nearest facility that does.”

“As physicians, we must continue to discuss the potential loss of ovarian function and fertility with every one of our breast cancer patients, just like we would do with any other side-effect of treatment: as early and extensively as possible,” Lambertini added. “It is important for oncologists to be aware of existing ESMO Clinical Practice Guidelines on the subject and to be attuned to the specific circumstances of each patient. Whilst this study reminds us that the need for fertility preservation measures should not be overestimated, we should also be careful not to exaggerate the risk of such a procedure to women when we offer them these options.”