A new analysis of 30-day post-surgery complications among more than 18,000 women with breast cancer undergoing bilateral (double) and unilateral (single) mastectomy with breast reconstruction finds that complications are generally rare for either type of surgery (the overall rate of complications is 5.3%).

Double mastectomy, however, is associated with higher rates of implant loss, the need for transfusion, and longer hospital stay, compared to unilateral surgery.

“The era of genetic testing has raised awareness about inherited forms of breast cancer. However, for the average-risk patient with breast cancer who does not have an inherited mutation, there is often an over-estimation of future risk, which may result in more extensive surgical procedures than are warranted,” said Julie Margenthaler, MD, Breast Cancer Symposium News Planning Team member.

“Women also need to be informed about the increased rates of implant loss, transfusion, and reoperation that are associated with bilateral mastectomy and reconstruction versus unilateral mastectomy with reconstruction.”

This is the largest study to date assessing complications from single vs. double mastectomy with reconstruction.

“Women choose surgery on their cancer-free breast for lots of different reasons, ranging from a desire to achieve a more symmetric look after surgery to fear of cancer coming back. Our findings show that both unilateral and bilateral procedures are safe overall, but bilateral mastectomy is associated with higher risks for certain complications,” said lead study author Mark Sisco, MD, clinical assistant professor of surgery at the University of Chicago Pritzker School of Medicine.

“These results are reassuring for women who are considering mastectomy with reconstruction and provide additional information that may weigh in their choice of surgery.”

The rate of contralateral prophylactic mastectomy (CPM) – an elective surgery to remove both the affected and the healthy breast in women who have cancer in only one breast – has increased five-fold in the last ten years.

For the vast majority of women, there is no evidence that this procedure will improve their survival.

However, for women with cancer in one breast who have a genetic predisposition for breast cancer, such as the BRCA gene mutation, or have a strong family history of breast cancer, evidence suggests that CPM may improve survival.

Researchers identified 18,229 women with breast cancer who were undergoing single or double mastectomy with reconstruction from the American College of Surgeons National Surgery Quality Improvement Program (NSQIP) database.

Most of the patients (64.3%) underwent single mastectomy, and most women in both groups received implant-based reconstruction (15,000 women in total; 88.6% of those undergoing bilateral surgery and 79.4% of those undergoing unilateral surgery), rather than autologous reconstruction – where tissue from other parts of the patient’s body is used to reconstruct the breast.

Complications arising within 30-days of surgery were assessed.

The analysis showed that among women with implant-based reconstruction, bilateral mastectomy was associated with higher rates of implant loss compared to unilateral surgery (1% vs. 0.7%) and greater likelihood of needing a second operation in the first 30 days (7.6% vs 6.8%).

Regardless of the type of reconstruction, double mastectomy was associated with higher rates of blood transfusion due to bleeding-related complications, particularly among women who underwent autologous reconstruction (3.4% women with single mastectomy surgery needed a transfusion compared to 7.9% of those with double mastectomy).

Transfusions occurred less frequently among women who received implant-based reconstruction (with a rate of 0.3% for single mastectomy and 0.8% for double mastectomy).

As expected, double mastectomy was associated with a longer hospital stay compared to single mastectomy (one day vs. two days for implant-based reconstruction; four vs. five days for autologous reconstruction).

Overall, the rates of medical complications such as pneumonia and heart problems were low and similar between the two groups.

Along with other evidence, the data from this study will inform the development of much-needed decision aids to help women trying to decide between single mastectomy and double mastectomy (CPM).

Source: ASCO