Recent population-based research indicates that omitting radiation therapy after breast-conserving surgery for older patients with early-stage, estrogen receptor (ER)–positive breast cancer does not compromise breast cancer-specific survival. While radiation is associated with modest overall survival gains, these are largely attributed to competing health factors rather than cancer recurrence.
For decades, standard treatment for early-stage breast cancer often included adjuvant radiation therapy following breast-conserving surgery (BCS). However, real-world data from the Surveillance, Epidemiology, and End Results (SEER) database suggests a distinct evolution in clinical practice. Between 2000 and 2022, the rate of radiation omission among women aged 70 or older with stage I, ER-positive cancer climbed from approximately 25% to over 40%.
According to the data, out of 50,845 patients analyzed, 36% did not receive radiation. Researchers found that while radiation was linked to a slightly better overall survival (aHR, 0.80), there was no statistically significant difference in breast cancer-specific survival (BCSS) between those who received radiation and those who did not.
Comparing Outcomes in Male Breast Cancer Cohorts
The trend toward conservative treatment is not limited to female patients. A separate analysis of early-stage, low-risk male breast cancer (MBC) patients—also utilizing the SEER-17 database—mirrors this shift. Among this population, the proportion of patients opting for non-radiation treatment rose from 70% to nearly 90% by 2020.
Researchers applied propensity score matching (PSM) to ensure a balanced comparison between the radiation (RT) and non-radiation (NRT) groups. Following this adjustment, the study of 360 male patients found that the use of radiation had no significant effect on overall survival (HR 0.93). Furthermore, the cumulative incidence of breast cancer-related death remained similar between the two groups, reinforcing the hypothesis that radiation can often be safely avoided in low-risk, early-stage cases.
The Role of Competing Mortality in Survival Metrics
A critical takeaway from these studies is the distinction between overall survival (OS) and breast cancer-specific survival (BCSS). In the female cohort, researchers observed that radiation was linked to a modest improvement in OS, yet they concluded this was likely driven by competing mortality
rather than the efficacy of the radiation itself. In other words, patients who received radiation may have had different baseline health profiles, leading to better survival outcomes that were not necessarily caused by the treatment.
In the male cohort, the impact of age and disease stage remained the most significant predictors of survival. Patients aged over 75 years experienced significantly worse overall survival compared to those in the 65–75 age range, regardless of whether they received radiation. This highlights that for older patients, the management of systemic health and comorbidities often carries more weight for long-term survival than the local treatment of the breast tumor.
Implications for Future Treatment De-escalation
The data suggests that clinical practice is increasingly moving toward personalized, selective treatment. For older patients with stage I, ER-positive breast cancer, the evidence supports a move away from routine radiation if the patient is appropriately selected. Subgroup findings within the female cohort specifically noted that patients with tumors smaller than 1 cm and those older than 80 years showed comparable BCSS results regardless of radiation status.
As medical communities continue to evaluate these trends, the focus remains on reducing treatment burden without compromising outcomes. The consistency of these findings across both male and female SEER-based studies suggests that the trend of radiation omission is a reasoned response to patient-specific risk profiles. Patients are encouraged to consult their healthcare providers to discuss whether radiation de-escalation is appropriate based on their specific tumor characteristics, age, and overall health status.
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