Breastfeeding After Breast Cancer Is Safe and Feasible – ESMO 2024 Findings

A Major Source of Concern

Pregnancy and breastfeeding are major sources of concern for young women treated for breast cancer. The ESMO 2024 Congress presented new data showing that breastfeeding after breast cancer treatment is both safe and feasible. The data indicate that breastfeeding does not increase the risk of breast cancer recurrence and poses no health risk to the child. This may provide considerable reassurance to women after breast cancer.

The Safety of Breastfeeding After Breast Cancer

Fertility preservation and pregnancy planning are priorities, particularly for young women diagnosed with and treated for early-stage breast cancer. However, misinformation about breastfeeding is common, and women may not receive enough support from healthcare professionals. Breastfeeding is not possible after bilateral mastectomy (removal of both breasts), but women who undergo breast-conserving surgery can breastfeed with one breast.

Studies show that breastfeeding with one breast is sufficient for newborn babies and even twins.

POSITIVE Trial Results Presented at ESMO 2024

POSITIVE (Pregnancy Outcome and Safety of Interrupting Therapy for Women with Endocrine Responsive Breast Cancer) was examined in a second analysis evaluating the effects of breastfeeding on breast cancer outcomes.

The POSITIVE trial aims to assess whether women with hormone receptor-positive early-stage breast cancer who have received at least 18 months of hormonal therapy can safely interrupt treatment temporarily to become pregnant.

A key design feature is that participants may interrupt hormonal therapy for up to 2 years, with monitoring of pregnancy and subsequent effects on recurrence risk during this period. Interim results showed no increase in short-term cancer events.

Second Analysis Results Presented at ESMO 2024: 

• In the study, 63% of women who gave birth and had not undergone bilateral mastectomy breastfed.
• Among the women, 37% breastfed for at least 6 months.
• Their average age was over 35, and most had not previously had children.
• Breastfeeding had no adverse effect on breast cancer recurrence over two years of follow-up.

These data suggest that women who have received breast cancer treatment should be encouraged to breastfeed.

RELATED TOPICS:

- Initial POSITIVE Trial Findings: Women With Breast Cancer Can Safely Interrupt Hormonal Therapy for Pregnancy

- Information on Embryo Freezing and Infertility Treatment for Cancer Patients

Breastfeeding in Women With BRCA Mutations

Another study presented at ESMO 2024 examined women carrying a BRCA mutation who were younger than 40 and had been diagnosed with stage I-III breast cancer.

• Of 4904 patients, 659 became pregnant after their breast cancer diagnosis and 474 gave birth.
• Among these women, 23% breastfed for an average of 5 months.
• The study found no adverse effect of breastfeeding on locoregional recurrence or the development of a second breast cancer.

This is an important finding for women carrying BRCA mutations, because breastfeeding and pregnancy are also considered safe for this group.

Long-Term Effects and Health Benefits

Breastfeeding is known to provide health benefits for mother and child after breast cancer treatment. However, its effect on the quality of life of women who have had breast cancer has not yet been fully investigated. Future studies may clarify its role in these women's biological and psychological recovery.

In conclusion, these studies show that women need more information and support about breastfeeding after breast cancer.