To the editor: We thank Dr. Hannoun-Levi for his interest in our recent publication [1]. With multidisciplinary coordination we demonstrated that surgical resection, pathologic confirmation of negative margin and lymph node status, and ICBB can all be completed in 5 business days using a 3-fraction ICBB regimen. Our routine practice on or off clinical trial is for final pathologic evaluation to be completed on the second postoperative day. We acknowledge Dr. Hannoun-Levi’s comment that limited pathology resources within some medical systems may impede such an accelerated therapy timeline. Nevertheless, our low toxicity rates combined with the potential proportional rise in infection risk with the duration of an indwelling foreign object suggest that prioritization of pathologic resources in patients undergoing ICBB should be encouraged.
With a median follow-up of 14 months we found a 3% incidence of breast infection, no grade 2 or higher AEs, and 95% of patients reported excellent or good breast cosmesis, which compares favorably with prior studies [2–9]. We agree that further follow-up is needed to assess long-term outcomes. That said, available data suggest that early cosmetic outcomes are predictive of late cosmetic outcomes. Specifically, the GEC–ESTRO study reported excellent or good cosmesis at 1-year and 5-years in 92% of patients who received catheter-based interstitial partial breast brachytherapy whereas early deterioration in cosmesis was observed in the RAPID trial [7, 8]. Extended follow-up over many years may not be necessary to identify promising regimens to carry forward into phase 3 trials.
ICBB has been associated with a unique treatment-related complication profile compared with external beam techniques characterized by higher rates of infection and seroma which can impact quality of life and increase health care costs [10]. We identified a 20% rate of grade 1 (asymptomatic) seroma at 3 months with a reduction to 8% by 1 year. None have required procedural intervention. This compares favorably with a 13% incidence from the MammoSite registry [4], and is similar to the incidence of grade 1–2 hematoma reported in the GEC–ESTRO trial (19% grade 1, 1% grade 2) [6], supporting the hypothesis that our treatment schedule may reduce brachytherapy-associated wound complications and improve the therapeutic ratio.
We agree that more work is needed to identify the “optimal” partial breast radiotherapy regimen which best balances oncologic efficacy, toxicity, cosmesis, convenience, and health care costs. Nevertheless, our early report is favorable, and may be an excellent ICBB option for appropriately selected patients.
Funding:
This research was supported by the Lawrence W. and Marilyn Matteson Fund in Cancer Research and K12 HD065987 (Robert W. Mutter)
Footnotes
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Conflicts of Interests: None.
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