Increasing omission of radiation therapy and sentinel node biopsy in elderly patients with early stage, hormone-positive breast cancer.

Abstract

Prospective evidence demonstrates that there is limited benefit of axillary staging with sentinel lymph node biopsy (SLNB) or radiation therapy (RT) in patients over age 70 with clinical stage I, hormone-positive breast cancer. The clinical impact of this literature is unknown. Our hypothesis is that omission of SLNB and RT has increased over time in these patients, and patient and tumor characteristics can predict when omission strategies are used. A single-center tumor registry was queried for all patients over age 70 with ER+, Her2/neu-negative, clinical T1N0 invasive breast cancer from 2009 to 2017, who underwent breast conservation (n=141). Date of treatment, age, tumor characteristics, use of SLNB, and use of RT were evaluated. The trend of treatment strategy over time was evaluated. Multivariable analysis was performed on the subgroup of patients after publication of the long-term follow-up CALGB 9343 data1 . Patients undergoing treatment with omission of RT and SLNB increased over the study period (P=.0006). Patients who did not receive RT were older (78.76years±5.48 vs 73.37±3.63, P<.01). There was no difference between tumor grade and size between uses of RT. Of patients who received SLNB (n=84), only 3 (3.5%) had a positive LN. On multivariable analysis of patients who were treated after publication of the CALGB 9343 data (2014-2017), only age was predictive of being treated with RT (OR, 0.77; 95% CI, 0.67-0.88). Omission of both RT and SLNB are increasing in clinical practice in appropriately selected patients. The likelihood that patients are offered omission of these interventions increases with age. Low nodal positivity rates suggest that this strategy may be underutilized. Tumor grade and size were not predictive of omission of RT in this group of low-risk patients. Long-term data are needed as these approaches are increasingly adopted.