Chadha et al are to be commended for their excellent review of repeat breast-conservation therapy after isolated in-breast local failures. We will briefly review several important points already made by the study authors.
First, in the present era of moderately effective systemic therapy, the importance of effective local therapy continues to be demonstrated across heterogeneous breast cancer populations—postlumpectomy, postmastectomy, and even metastatic patients appear to live longer when local therapy is optimized.[1-3] It seems quite reasonable, then, to assume that the same should be true in women who have isolated ipsilateral breast tumor recurrences (IBTRs) after breast-conservation therapy. Chen et al have analyzed IBTR patients in the Surveillance, Epidemiology and End Results (SEER) database, and their findings support the importance of aggressive local therapy in this subset of patients. The authors correctly note that all women in this situation should be offered mastectomy as standard-of-care local therapy, and less radical therapy should be considered only with great caution outside the context of a clinical trial.
Importance of Reirradiation
Second, for women desiring breast conservation, even in the face of an IBTR, the maxim of offering comprehensive local therapy should, in our opinion, continue to hold true. Indeed, as summarized in the Chadha et al review, reports of breast-conserving surgery alone without reirradiation have resulted in subsequent local failure rates that are, on average, higher than those reported for repeat surgery followed by repeat radiation therapy. While these single-institution comparisons come with many caveats, the results seem to be consistent.
Two of these studies warrant special attention: one by Hannoun-Levi, noteworthy for its large size (N = 69) and long follow-up (median of 50 months after the salvage therapy), and one by Chadha and colleagues, of note for its prospective design. It should be stressed that both of these studies—offering probably the most reliable and mature results of repeat breast-conserving therapy—were done with low–dose-rate multicatheter implants at centers with significant brachytherapy experience. This fact somewhat mitigates against the portability of this approach, given the current limited expertise available for multicatheter interstitial breast implants in North America. In this regard, the prospective Radiation Therapy Oncology Group (RTOG) trial of external-beam conformal partial-breast reirradiation, referred to in the Chadha article, may be studying an approach that is more feasible for wider use than brachytherapy strategies.
Whatever radiation technique one uses in considering repeat breast-conserving therapy for in-breast relapses, careful selection of patients, meticulous attention to detail regarding target volumes, dosimetry and dose to nontarget tissues in the previously radiated patient, appropriate informed consent regarding risks/benefits and alternatives, and close follow-up are essential. These factors can best be achieved in the setting of a prospective trial. The knowledge gained from these trials will ultimately help to guide women who prefer a second chance of breast preservation for in-breast relapses.
Financial Disclosure: The authors have no significant financial interest or other relationship with the manufacturers of any products or providers of any service mentioned in this article.