RT AFTER POSTMASTECTOMY IMPLANTS

SAN ANTONIO, TX — Women who received postmastectomy radiation therapy (RT) experienced higher complication rates if they had implant reconstruction compared with autologous reconstruction, according to the large, prospective, multicenter Mastectomy Reconstruction Outcomes Consortium study.

"The impact of radiotherapy on breast reconstruction is widely feared but poorly understood," said investigator Reshma Jagsi, MD, DPhil, professor and deputy chair in the department of radiation oncology at the University of Michigan, who reported the results here at the 2016 San Antonio Breast Cancer Symposium.

RT can cause skin changes, vascular compromise, and fibrosis which may compromise the viability and outcomes of breast reconstruction, necessitating repeat interventions for correction, Dr Jagsi explained.

She continued: "These data are critical to inform the growing number of patients who are considering post-mastectomy radiotherapy and who may desire breast reconstruction, so that they may make informed and preference-concordant decisions."

The study included 553 radiated and 1461 nonradiated postmastectomy patients, median age 49 years, who received either implant or autologous reconstruction at 11 institutions.

After adjusting for a long list of covariates including extent of disease, reconstruction timing, nodal management, bilateral or unilateral reconstruction, and chemotherapy receipt, the study showed that, by 2 years, complications such as wound infections or hematomas had occurred in 33.4% of radiated patients compared with 23.5% of nonradiated patients.

"The excess of these complications occurred in the radiated implant patients," explained Dr Jagsi, noting that 38.9% of radiated implant patients experienced at least one complication compared with 25.6% of radiated patients with autologous reconstruction, 21.8% of nonradiated patients with implants, and 28.3% of nonradiation patients with autologous reconstructions.

On multivariate analysis, compared with no radiation, radiation therapy was associated with a 2.64 times higher odds of complications by 2 years in implant patients (P < .001), while showing no significant difference in autologous reconstruction patients.

Similarly, among radiated patients, autologous reconstruction was associated with a lower 2-year risk for complications than implant-based reconstruction (odds ratio, 0.47; P = .007).

At 2 years, reconstructive failure had occurred in 11.4% of radiated patients and 3.4% of nonradiated patients, largely due to the excess failure rate in radiated implant patients (18.7%) compared with that in nonradiated implant patients (3.7%), and autologous reconstruction patients — both radiated (1.0%) and nonradiated (2.4%), she said.

Patient-reported satisfaction with outcome and breast satisfaction were consistent with these findings, she added.

Asked by Medscape Medical News to comment on the findings, Susan Boolbol, MD, chief of the division of breast surgery at Mount Sinai Health System Cancer Network in New York said, "This study addresses an incredibly important topic for breast cancer patients."

She explained that, only in the past several years have the indications and use of postmastectomy radiation increased.

"This study is an important contribution to the literature due to the fact that post mastectomy radiation is now commonly performed. The majority of women diagnosed with breast cancer will undergo treatment and never have another issue from the actual cancer again. This is why the possible side effects of the treatments and the quality of life issues are so important," She said.

Dr Boolbol emphasized that "the study is not saying that patients having post mastectomy radiation, should not have implant based reconstruction. The study does state that the complication rates are higher but this does not mean that it is not safe to perform."

She added, "unfortunately, there are many times that we do not know that post mastectomy radiation will be indicated. But, for the situations where we are aware that the patient will require it, this study will help with our discussions regarding options for reconstruction."

The study was funded by the National Cancer Institute.

Dr Jagsi and Dr Boolbol have disclosed no relevant financial relationships. 

San Antonio Breast Cancer Symposium (SABCS) 2016: Abstract S3-07. Presented December 8, 2016.