Douglas W. Arthur, MD
Findings from the phase II NRG Oncology/RTOG 1014 trial, reported in JAMA Oncology by Douglas W. Arthur, MD, and colleagues showed that partial-breast reirradiation after second lumpectomy for recurrence of ipsilateral breast cancer following previous whole-breast irradiation was an effective treatment approach and could constitute an alternative to mastectomy in this setting.
The study, which opened in June 2010 and closed in June 2013, included 58 evaluable patients with unifocal tumor recurrence < 3 cm at more than 1 year after breast-conserving therapy with whole-breast irradiation and excision with negative margins. Patients received lumpectomy plus adjuvant three-dimensional conformal partial-breast reirradiation at 1.5 Gy twice daily for 30 treatments over 15 days (total = 45 Gy). The current analysis included data through November 2018.
Overall, 23 recurrences (40%) were noninvasive and 35 (60%) were invasive; tumors were ≤ 2 cm in 53 patients (91%); and all recurrences were node-negative. A total of 44 patients (76%) were positive for estrogen receptor; 33 (57%), for progesterone receptor; and 10 (17%), for HER2 overexpression.
The median follow-up was 5.5 years. Recurrence was observed in four patients, with a 5-year cumulative incidence of 5%. Ipsilateral mastectomy was performed in seven patients, with a 5-year cumulative incidence of 10%. At 5 years, the distant metastasis-free survival rate was 95% and overall survival was 95%.
Treatment-related late adverse events (more than 1 year after completion of partial-breast reirradiation) consisted of grade 1 events in 14 patients (25%), grade 2 events in 15 (26%), and grade 3 events in 4 (7%). Breast skin and fibrosis changes were the most common adverse events of any grade; grade 3 adverse events consisted of breast infection, fibrosis of deep connective tissue, breast atrophy and pain, and skin induraton.
The investigators concluded, “For patients experiencing recurrence of breast cancer in the ipsilateral breast after lumpectomy and whole-breast irradiation, a second breast conservation was achievable in 90%, with a low risk of re-recurrence of cancer in the ipsilateral breast using adjuvant partial-breast reirradiation. This finding suggests that this treatment approach is an effective alternative to mastectomy.”
Arthur DW et al: JAMA Oncol. November 21, 2019 (early release online). ■