Top Line: While not designed to answer this question, recent investigations have pointed to the power of Oncotype recurrence scores (ORS) in prognosticating locoregional recurrence following resection of breast cancer.
The Study: This begs the question of whether we should incorporate this information into our calculus on the ever-controversial decision of when to add regional nodal irradiation (RNI) for pN1 disease. Enter this secondary analysis of RxPONDER, the prospective randomized trial demonstrating pre-menopausal but not post-menopausal women with pN1 ER+/HER2- disease and an ORS ≤25 benefit from the addition of chemo to endocrine therapy. Overall, 81% received adjuvant RT. Of the 3001 women who received breast-conserving surgery with adjuvant radiation, 53% included RNI. Of 1724 patients who had mastectomy, 54% received radiation with 81% of these including RNI. The takeaway here is these women had low rates of locoregional recurrence at 5 years regardless of which iteration of systemic therapy and/or radiation was received: 0.85% after breast-conserving surgery and RT with RNI, 0.55% after breast-conserving surgery and RT without RNI, 0.11% after mastectomy with PMRT, and 1.7% after mastectomy without PMRT. A notable finding was that LRR risk was significantly lower after breast-conserving surgery and RT versus mastectomy without RT in premenopausal patients. Another finding was that RNI did not improve LRR risk in the subset of patients randomized to endocrine therapy alone. Now, they did what they could to control for all available risk factors like tumor size, extent of axillary surgery, menopausal status and ORS but ultimately RNI was added per physician discretion for a reason, and it’s impossible to know how the women who received RNI would have fared without it until a prospective randomized evaluation.
TBL: Most patients with pN1 ER+/HER2- breast cancer with ORS ≤25 appear to have less than 1% risk of locoregional recurrence at 5 years with adjuvant radiation with or without RNI. | Jasgi, JAMA Oncol 2023
The Study: This begs the question of whether we should incorporate this information into our calculus on the ever-controversial decision of when to add regional nodal irradiation (RNI) for pN1 disease. Enter this secondary analysis of RxPONDER, the prospective randomized trial demonstrating pre-menopausal but not post-menopausal women with pN1 ER+/HER2- disease and an ORS ≤25 benefit from the addition of chemo to endocrine therapy. Overall, 81% received adjuvant RT. Of the 3001 women who received breast-conserving surgery with adjuvant radiation, 53% included RNI. Of 1724 patients who had mastectomy, 54% received radiation with 81% of these including RNI. The takeaway here is these women had low rates of locoregional recurrence at 5 years regardless of which iteration of systemic therapy and/or radiation was received: 0.85% after breast-conserving surgery and RT with RNI, 0.55% after breast-conserving surgery and RT without RNI, 0.11% after mastectomy with PMRT, and 1.7% after mastectomy without PMRT. A notable finding was that LRR risk was significantly lower after breast-conserving surgery and RT versus mastectomy without RT in premenopausal patients. Another finding was that RNI did not improve LRR risk in the subset of patients randomized to endocrine therapy alone. Now, they did what they could to control for all available risk factors like tumor size, extent of axillary surgery, menopausal status and ORS but ultimately RNI was added per physician discretion for a reason, and it’s impossible to know how the women who received RNI would have fared without it until a prospective randomized evaluation.
TBL: Most patients with pN1 ER+/HER2- breast cancer with ORS ≤25 appear to have less than 1% risk of locoregional recurrence at 5 years with adjuvant radiation with or without RNI. | Jasgi, JAMA Oncol 2023