Partial Breast Irradiation in Second Cancers
Dear OncoLink "Ask The Experts,"
A friend has recently been diagnosed with invasive lobular breast cancer, HER-2/neu positive, ER/PR positive. She had invasive ductal cancer 10 years ago with a full course of radiation. She is considering lumpectomy + Mammosite OR mastectomy. Is there data on success rates for each choice for a person in her situation?
Terry Styles, MD, Assistant Professor of Radiation Oncology at the University of Pennsylvania, responds:
The standard recommendation for a patient who develops a second cancer in the same breast, after prior lumpectomy and whole breast radiotherapy, would be to proceed to mastectomy. As this appears to be a second primary and not a recurrence of the first cancer, and as long as the tumor is small and excised completely with negative margins in the mastectomy specimen (i.e., no tumor on the cut edge of the mastectomy) and there are no lymph nodes involved, the patient would not require additional radiation and would have a relatively good prognosis.
Newer treatment methods such as partial breast irradiation (PBI) are now being used for breast conservation in breast cancer patients at first presentation. PBI is often performed with a Mammosite balloon and is still being actively evaluated. However, it shows significant promise in terms of decreasing the chance of cancer recurrence in the breast with good cosmetic outcome.
The excellent results seen in newly diagnosed breast cancer patients make it attractive to explore use of PBI in patients who have already received radiation to the breast. This would allow lumpectomy and re-irradiation of a smaller portion of the breast in an attempt to avoid mastectomy. The use of this treatment method and technology is even more experimental in this setting, and only small, single institution studies have been performed to assess the safety and tolerability of this option. Overall, these studies have shown PBI to be a possible intervention. However, in the absence of a large, multi-institutional, randomized trial directly comparing mastectomy to lumpectomy plus mammosite in this setting, one cannot state that these are equivalent treatments in terms of safety, efficacy, or cosmesis. That being said, I do think it is worth exploring but should only be done as part of a clinical trial.
See OncoLink's Expert on Call podcast about PBI.