Comparing survival after mastectomy and lumpectomy in patients with early-stage breast cancer

The study compared survival rates in patients with early stage breast cancer treated with mastectomy versus lumpectomy plus radiation therapy.

Most breast cancers grow in response to female hormones (estrogen or progesterone), via their receptor (a protein found on the surface of the cancer cells). These cancers are called hormone receptor-positive (HR+) breast cancers. Other types of breast cancer do not have these receptors and are called hormone receptor-negative (HR-) breast cancers. Early stage breast cancer is cancer confined to the breast tissue. Treatment for this stage is generally surgery. There are several types of surgery available for these patients. A mastectomy is the complete removal of the breast. Another option may be breast conserving surgery (lumpectomy), in which only the cancer is removed, leaving the rest of the breast tissue in place. Lumpectomy has been used together with radiation therapy to make sure that all cancer cells have been removed. This combination is called breast-conserving treatment (BCT). Previous studies comparing lumpectomy and mastectomy have shown equal efficacy between the two types of surgery. This study aimed to compare the efficacy in terms of overall survival or OS (defined as the percentage of patients who survived for a certain period of time) and disease-specific survival or DSS (defined as the percentage of patients who have not died because of breast cancer for a certain period of time) of mastectomy versus lumpectomy plus radiation therapy (BCT) in patients with early stage breast cancer. 

A total of 112154 patients diagnosed with early stage breast cancer were included in the study. 61771 of these patients underwent BCT, while 50383 had mastectomy without radiation therapy. Patients were followed up for approximately 9 years and OS and DSS were evaluated. Patients treated with BCT had a 19% higher OS compared to those treated with mastectomy. Additionally, patients over 50 years old with HR+ breast cancers treated with BCT had a higher DSS compared to those younger than 50 with HR- breast cancers. 

In summary, patients with early-stage breast cancer treated with BCT had improved DSS and OS compared to those treated with mastectomy.