Changing practice patterns of adjuvant radiation among elderly women with early stage breast cancer in the United States from 2004 to 2014

Abstract

Randomized controlled trials (RCTs) have challenged the need for routine radiation therapy (RT) in women ≥ age 70 with favorable early stage breast cancer (BC) due to modest improvement in local control and no survival benefit. We studied practice patterns in RT among elderly women in the United States. We analyzed data from the National Cancer Database (NCDB) of women ≥age 70 diagnosed with T1 or T2 and N0 invasive BC treated with breast conservation surgery (BCS) between 2004 and 2014. Patients were divided into four groups: (1) no RT, (2) partial breast irradiation (PBI); (3) hypofractionation (HF); and (4) conventional whole breast RT (CWBI). Univariable and multivariable analyses (MVA) were performed to compare characteristics among the four RT groups. A subgroup analysis of women with favorable disease (T1N0 ER + HER2‐) was also performed with similar statistical comparisons. Of the 66,126 meeting eligibility, 9,570 (14.5%) had PBI, 16,340 (24.7%) had HF, and 40,117 (60.7%) had CWBI. Only 99 patients (0.15%) had RT omitted. Omission of RT increased marginally from 0.04% in 2004 to 0.24% in 2014. MVA identified older age (OR 1.18, CI 1.08‐1.28), more comorbidities (Charlson‐Deyo Score of 1) (OR 3.36, CI 1.29‐8.72), and no hormone therapy (OR 22.07, CI 5.79‐84.07) as more likely to have RT omitted. The use of HF increased from 3.9% to 47.0%, P < .001 with a concomitant decrease in CWBI from 88% to 41%, P < .001. MVA identified older age, treatment location, and omission of chemotherapy as associated with HF. No significant differences from the larger cohort were found among the T1N0 subgroup analysis. Despite RCT evidence, omission of RT was rare in the United States, suggesting that more effective outreach methods to disseminate clinical guideline information may be needed.

The addition of radiotherapy to breast-conserving surgery improves survival for elderly patients with early breast cancer

“…Therefore, competing mortality is a major factor affecting survival in elderly BC patients. However, several studies have shown that comorbidities, education level, area of residence, receipt of endocrine therapy, and distance to the nearest RT clinic were not associated with the omission of RT after BCS in this population ( 14 , 19 ). In clinical practice, age, marital status, and tumor grade were the main factors associated with RT decision-making in the elderly ( 14 , 19 ).…”

“…However, several studies have shown that comorbidities, education level, area of residence, receipt of endocrine therapy, and distance to the nearest RT clinic were not associated with the omission of RT after BCS in this population ( 14 , 19 ). In clinical practice, age, marital status, and tumor grade were the main factors associated with RT decision-making in the elderly ( 14 , 19 ). In our study, we also found that patients with younger age and higher tumor grade were more likely to receive RT.…”

Physicians’ Opinion on Intraoperative Radiotherapy as a Therapeutic De-Escalation Option in Older Women with Early Breast Cancer

“…According to the latter, radiation omission is not an option after BCS, and IORT has been very recently recommended (after this survey was performed) for highly selected patients [ 13 ]. In our study, there is no consensual agreement between physicians for IORT, and none of them were willing to propose radiation omission even in the context of clinical trial and knowing that it was considered a therapeutic option in several countries [ 9 ]. Of note, even in countries that recommend radiation omission as a de-escalation option, there is no consensus among radiation oncologists and surgeons.…”

“…Semi-structured interviews were conducted with open-ended questions on IORT, de-escalation, and patients’ information needed to participate in such decision making. Radiotherapy omission was also systematically discussed as proposed in several countries [ 9 ].…”

“…Other randomized controlled trials showed a significant advantage of WBRT after BCS on local control compared to endocrine therapy alone but no benefit in terms of overall survival in older women with estrogen-receptor-positive EBC [ 7 , 8 ]. Based on these findings, the U.S. national guidelines recommended omitting adjuvant radiotherapy after BCS for EBC women 70 years of age and older who are prescribed endocrine therapy [ 9 ]. However, whether radiotherapy is beneficial in the elderly is still a matter of debate, with results of recent studies using observational real-world data reporting higher mortality rates in those who did not receive radiotherapy after BCS [ 10 , 11 ].…”