Omission of radiation therapy following breast conservation in older (≥70 years) women with T1‐2N0 triple‐negative breast cancer

Abstract

Background Although randomized data support omitting adjuvant radiotherapy (RT) following breast conservation for T1‐2N0 estrogen receptor positive breast cancer in ≥70‐year‐old women, there remains a knowledge gap regarding its omission for triple‐negative BC (TNBC). Methods and materials The National Cancer Database (NCDB) was queried for ≥70‐year‐old females with newly diagnosed T1‐2N0M0 TNBC treated with breast conservation. Multivariable logistic regression ascertained factors associated with adjuvant RT administration. Overall survival (OS) between patients treated with or without adjuvant RT was estimated using the Kaplan‐Meier method. Cox proportional hazards modeling determined variables associated with OS. Results Of 8526 patients, 6283 (74%) patients received adjuvant RT, and 2243 (26%) did not. RT was more frequently withheld in older patients, those with higher comorbidities, lower income, pT2 disease, following margin‐positive resection, receipt of chemotherapy, and at academic centers (P < 0.05 for all). Median follow‐up was 38.0 months. Five‐year OS was greater in the adjuvant RT group (77.2% vs 55.3%, P < 0.001); these differences persisted when stratifying for age, T stage, and chemotherapy utilization (P < 0.001 for all). Omission of RT was also independently associated with poorer OS on multivariate analysis (P < 0.001). Conclusions This investigation, the largest known such study to date, observed that omission of adjuvant RT for elderly women with T1‐2N0 TNBC was associated with poorer OS; this was observed across a range of age groups, as well as following stratification by T stage and chemotherapy usage. Although these results do not imply causation, caution must be exercised when considering omission of adjuvant RT in node‐negative TNBC patients.

Altered fractionation in radiation therapy for breast cancer in the elderly: are we moving forward?

“…In the Propensity Score-matched sample, patients who had received RT plus HT revealed a 38% lower risk of death compared with patients who were treated with only HT ( 12 ). Additional data have been recently showed in a National Cancer Database study ( 13 ). The authors evaluated overall survival (OS) between patients with triple negative breast cancer after BCS who either received postoperative RT or not.…”

“…A statistically significant decrease of OS was observed across a range of age groups, as well as pT stage and chemotherapy usage stratification. The authors warned about the study limitations, nevertheless they suggest caution in omitting adjuvant RT in this setting ( 13 ).…”

Cancer-Specific Outcomes in the Elderly with Triple-Negative Breast Cancer: A Systematic Review

“…Despite the paucity of data, our study demonstrated that elderly patients with TNBC were less likely to receive adjuvant therapy, including both chemotherapy and radiotherapy. A chronological age threshold of ≥70 and ≥80 was independently associated with the decreased use of radiotherapy in two independent analyses [ 13 , 14 ]. A lower rate of radiotherapy was also influenced by a higher number of comorbidities, lower income and receipt of chemotherapy.…”

“…A lower rate of radiotherapy was also influenced by a higher number of comorbidities, lower income and receipt of chemotherapy. Margin-positive resection and disease >2 cm were also associated with a lower likelihood of adjuvant radiotherapy, which may suggest a more palliative approach in these patients [ 13 , 14 ]. One study found that despite being offered radiotherapy, elderly patients were also more likely to refuse treatment [ 12 ].…”

“…However, the benefits seen in survival may be attributed to the selection of healthier individuals. Radiation was more likely to be omitted in elderly patients with a higher number of comorbidities [ 13 , 14 , 18 , 19 , 20 ]. In our study, we examined BCSS as opposed to OS due to the competing risk of mortality from associated comorbidities and age.…”