Do regional practice patterns for radiotherapy for ductal carcinoma in situ (DCIS) breast cancer increase the likelihood of mastectomy when there is a second breast cancer in women who did not receive radiotherapy at the initial DCIS diagnosis?

In a new article published online by JAMA Oncology, Rinaa S. Punglia, M.D., M.P.H., of Harvard Medical School, Boston, and coauthors used population-based databases to examine regional radiotherapy practice patterns for DCIS and their effect on the use of mastectomy.

Radiotherapy usually necessitates mastectomy, should a new cancer or DCIS develop in the same breast during a patient's lifetime.

Previous radiotherapy can complicate reconstructive options following a mastectomy.

Patients who receive breast-conserving surgery (BCS) alone may be candidates for subsequent BCS if there is a second breast cancer in the same breast.

The authors had data for 2,679 women (average age 64) with a diagnosis of DCIS between 1990 and 2011 and for 757 women (average age 79) with a DCIS diagnosis between 1991 and 2009 who had not undergone radiotherapy for DCIS and experienced a subsequent breast cancer or DCIS diagnosis.

The study separated patients into clusters based on health service areas (HSAs) and radiotherapy use.

The authors report that women who lived in an area with greater radiotherapy with BCS were more likely to undergo mastectomy if they had a second breast cancer even though they were candidates for BCS since they had initially foregone radiotherapy.

The study noted limitations because of the database used.

"Physicians in regions of high use of radiotherapy may guide patients with DCIS toward mastectomy because many of these patients are ineligible for BCS at the time of a second breast event -- having already received radiotherapy -- leading to mastectomy being recommended for patients who did not receive radiotherapy and are eligible for BCS. Awareness of this effect of practice patterns may be the first step toward its eradication and movement toward more patient-centered care," the authors conclude.

Source: JAMA Oncology