M. G. Shah-Khan1, L. Woldanski1, A. L. Kong1 1Medical College Of Wisconsin,Surgical Oncology,Milwaukee, WI, USA
Introduction:
Patient adherence to prescribed endocrine therapy for breast cancer is variable in both the preventative and adjuvant setting. For patients undergoing breast conserving surgery (BCS), there is data to support forgoing radiation therapy in older women with estrogen receptor positive (ER+) disease. We sought to determine the rate of initiation and adherence to endocrine therapy in patients undergoing lumpectomy without radiation therapy, and determine the rate of recurrence in these patients.
Methods:
A retrospective review was performed to identify patients treated within our institution from 2000-2014. Patients included were aged 60 and older and underwent BCS for ER+ invasive cancer (T1-T2) or DCIS, and did not undergo adjuvant radiation therapy. Chart review was performed to determine the rate of initiation and subsequent adherence to endocrine therapy. Recurrence and survival information was also evaluated.
Results:
A total of 206 patients were evaluated, with mean age of 76. Mean follow up was 49 months. One hundred forty three patients underwent BCS for invasive cancer, and 63 patients for DCIS. Of the patients with invasive cancer, 89% (n=127) were T1, and 11% (n=16) were T2. Seventy percent were lymph node negative, 7% were lymph node positive, and 23% had no lymph nodes evaluated. Sixty eight percent (n=97) initiated endocrine therapy with either tamoxifen or an aromatase inhibitor. Forty nine patients (30%) adhered to treatment for greater than 2 years, with 19% completing at least 4 years of treatment. A total of 14 (10%) of patients had a recurrence in the study period. Twelve patients (8%) had an ipsilateral locoregional recurrence, and 1 patient had a distant recurrence. One patient developed a contralateral primary invasive breast cancer during follow up. Twenty six percent of patients (n=37) died during the follow up period, with one death related to metastatic breast cancer.
Patients undergoing lumpectomy for DCIS had a lower rate of initiation of therapy, however rate of compliance over time was not significantly different. Only 35% of DCIS patients (n=22) initiated endocrine therapy, compared to 68% of patients with invasive cancer (p<0.0001). Twenty percent of patients (n=13) completed at least 2 years of therapy. Thirteen percent (n=8) of patients completed at least 4 years of therapy. Four patients (6%) developed a recurrence, 2 with ipsilateral DCIS, and 2 with contralateral primary breast cancers (1 DCIS, 1 invasive). Three patients (4.7%) died during the study period, with no breast cancer related deaths.
Conclusion:
In older patients undergoing BCS for T1-T2 ER+ in situ or invasive breast cancer who forego adjuvant radiation, initiation of endocrine therapy is higher in patients with invasive cancer than with DCIS, however compliance decreases in both groups over time. A low incidence of recurrence and breast cancer related mortality was seen in both groups of patients.