10: Potential Overtreatment of DCIS in Patients with Limited Life Expectancy

Low rates of locoregional recurrence and mortality among older adults with ductal carcinoma in situ (DCIS) suggest an opportunity for de-escalation of therapy. Moreover, as the benefits of intensive locoregional therapy are realized over a long timeframe, life expectancy (LE) should play a role in treatment decision-making. We examined whether a patient’s LE was associated with extent of locoregional treatment among women ≥ 70 with DCIS.


Methods: Women > 70 with < 5 cm of radiographic DCIS diagnosed between 2010-2015 were identified in the SEER-Medicare dataset. Patients with bilateral breast cancer, previous breast cancer, prior radiation therapy (RT) or diagnosis at death were excluded. Patients were categorized by LE ≤ 5 years or LE > 5 years as defined by Tan et al’s validated claims-based measure. The primary outcome was intensity of locoregional therapy: mastectomy + axillary surgery, mastectomy-only, lumpectomy + RT + axillary surgery, lumpectomy + RT, lumpectomy-only, and no treatment. Differences in treatment receipt by LE were assessed using Pearson chi square tests. A multivariate regression model was used to identify factors associated with rates of lumpectomy only, adjusting for other patient and disease-level factors.


Results:

Of 5346 women who met inclusion criteria, 927 (17.3%) had a LE ≤ 5 years. Median age was 75 years (range 70-97 years). In an unadjusted analysis, compared to patients with a LE > 5 years, more patients with LE ≤ 5 years underwent lumpectomy-only (39.4% vs 27.0%, p< 0.001), mastectomy without axillary surgery (8.1% vs 5.3%, p< 0.001) or no treatment (5.8% vs 3.2%, p< 0.001; Table). Seven hundred ten (17.6%) women underwent lumpectomy with axillary surgery. Although there was no significant difference in women undergoing lumpectomy + axillary surgery by LE, a significantly lower percentage of women with a LE ≤ 5 years underwent lumpectomy + axillary surgery + RT compared to those with a LE > 5 years (6.5% vs 9.7%, p=0.002). After adjusting for ER-status, tumor grade, race/ethnicity, SEER region, and income, women with LE ≤ 5 years had a significantly greater likelihood of undergoing lumpectomy-only (OR 1.90, 95% CI [1.63-2.22]).


Conclusions:

Limited LE is associated with lower-intensity locoregional therapy for DCIS in women ≥ 70 years, yet a significant proportion of these women with a limited LE still receive RT and axillary surgery, highlighting potential overtreatment. As the incidence of breast cancer rises in an aging US population, clear consensus on opportunities for de-escalation of locoregional therapy in older patients with limited LE is needed.