Top Line: Not for lack of trying, a clear consensus on when to offer post-mastectomy radiation (PMRT) remains elusive.
The Study: Most of the confusion stems from just how many clinically-relevant variables we have to factor when it comes to breast cancer: age, menopausal status, tumor size and location, tumor subtype and genomic risk, lymphovascular space invasion, extent of nodal involvement, extent of nodal dissection, extent of response to neoadjuvant systemic therapy…we could go on and on. Layer on top the rapidly emerging changes in systemic therapy practices, not to mention the individualized value judgment on just how much oncologic advantage would make it worth it to the patient sitting across from you. Here we have the American Radium Society PMRT appropriate use criteria. To be clear, the controversy largely lies in stage II disease, with the authors pointing out virtually all stage III disease stands to benefit from PMRT regardless of response to neoadjuvant therapy. A couple of interesting questions in 2023 include how to address 1-2 involved sentinel nodes when no completion axillary lymph node dissection (ALND) follows—an increasingly common scenario in the wake of AMAROS? “Omission of ALND in the setting of positive sentinel lymph nodes during mastectomy likely warrants the use of post mastectomy radiation to deliver regional lymph node irradiation.” Another is how do we factor in response to neoadjuvant systemic therapy?” PMRT is indicated for all patients with residual positive nodes after NAC and should be strongly considered for those with clinical nodal disease at diagnosis even with pathologic response to NAC (ypN0).”
TBL: While this document doesn’t clearly come down on one side or the other regarding PMRT, it does provide a nice summary of contemporary data for common PMRT scenarios. | Novick, Int J Radiat Oncol Biol Phys 2023
The Study: Most of the confusion stems from just how many clinically-relevant variables we have to factor when it comes to breast cancer: age, menopausal status, tumor size and location, tumor subtype and genomic risk, lymphovascular space invasion, extent of nodal involvement, extent of nodal dissection, extent of response to neoadjuvant systemic therapy…we could go on and on. Layer on top the rapidly emerging changes in systemic therapy practices, not to mention the individualized value judgment on just how much oncologic advantage would make it worth it to the patient sitting across from you. Here we have the American Radium Society PMRT appropriate use criteria. To be clear, the controversy largely lies in stage II disease, with the authors pointing out virtually all stage III disease stands to benefit from PMRT regardless of response to neoadjuvant therapy. A couple of interesting questions in 2023 include how to address 1-2 involved sentinel nodes when no completion axillary lymph node dissection (ALND) follows—an increasingly common scenario in the wake of AMAROS? “Omission of ALND in the setting of positive sentinel lymph nodes during mastectomy likely warrants the use of post mastectomy radiation to deliver regional lymph node irradiation.” Another is how do we factor in response to neoadjuvant systemic therapy?” PMRT is indicated for all patients with residual positive nodes after NAC and should be strongly considered for those with clinical nodal disease at diagnosis even with pathologic response to NAC (ypN0).”
TBL: While this document doesn’t clearly come down on one side or the other regarding PMRT, it does provide a nice summary of contemporary data for common PMRT scenarios. | Novick, Int J Radiat Oncol Biol Phys 2023