TNBC is associated with poor outcome. Treatment is limited to the use of chemotherapy to reduce the risk of recurrence. However, there are no large, randomized studies on the use of this therapeutic modality in older women with early TNBC. Even the National Comprehensive Cancer Network guidelines indicate that data are too limited to make recommendations on the use of adjuvant chemotherapy in older women with TNBC.
To help answer the question, investigators conducted a real-world benefit/risk analysis of adjuvant chemotherapy on recurrence-free survival (RFS), breast cancer–specific survival (BCSS), and overall survival (OS) rates in women aged 65 years and older with TNBC.
The data from the National Cancer Center in China were screened from January 1, 2010, and December 31, 2016, for women aged 65 years and older who had stage I through III invasive TNBC. Patients were excluded from this retrospective analysis if they had had recurrent or metastatic BC, noninvasive BC, bilateral BC, other active malignancies; had not undergone a surgical intervention; had T1aN0M0 disease; had incomplete estrogen or progesterone- or HER2- receptor status; or if no survival follow-up data were available. Patients were considered to have received chemotherapy if they completed at least one cycle of treatment. Patients who received chemotherapy doses of less than 85% of the recommended dose constituted the "dosage-decreased" group.
The primary endpoint was RFS, which was defined as the time from primary treatment (i.e., surgery or preoperative chemotherapy) to the time of the first documented invasive BC recurrence event (i.e., local, distant, combined events or contralateral BC). BCSS and OS were calculated from the date of primary treatment to the date of death or last follow-up.
A total of 1,593 women were diagnosed with stages I through III invasive BC during this study period. Of these, 186 women had TNBC. Nine patients were either lost to follow-up or they did not meet study criteria and were excluded from further analysis. The data were presented for 177 older women with a median age of 69 years (range: 65-86 years). Almost all patients (97.7%) had a Charleston Comorbidity Index score of 0 to 2, with 60% having a score of 0. All of the patients had undergone surgery, but only one-third (33.9%) received adjuvant radiation.
Of this group of 177 older women, 127 received chemotherapy with the majority (71.8%) receiving chemotherapy, mostly adjuvant chemotherapy (91.3%). Among the regimens administered were taxane plus carboplatin (35.4%); anthracycline-and-taxaneÐbased regimens (28.3%); taxane-based regimens (18.1%); capecitabine (6.3%); an unspecified regimen, taxane, or other (3.1% each); and an anthracycline plus cyclophosphamide (1.6%).
Those who received chemotherapy were significantly younger, had more advanced disease, had more positive lymph nodes, had a better ECOG status, and were more likely to receive radiation compared with those who did not receive chemotherapy; however, they did not have more comorbidities. Chemotherapeutic regimens varied significantly based on patient age and disease stage, with anthracycline-and taxane-based regimens being preferred in the 65- to 69-year-old group, whereas carboplatin-based regimens were more likely administered to those aged 70 years and older; the former group was more likely to have an earlier stage of disease and two positive nodes.
Fewer than one-tenth of patients (9.4%) discontinued chemotherapy due to intolerance (e.g., gastrointestinal effects, myelosuppression, fatigue), and almost one-half (45.5%) received a reduction in their dose, most notably because of neutropenia.
The 5-year RFS rate among those receiving chemotherapy was 83.3% versus 81.7% among those who were not given antineoplastics. The 5-year BCSS rate was 93.7% and 90.0%, respectively, in these groups. The 5-year OS rate was 91.1% versus 80.7% in chemotherapy-treated versus non–chemotherapy-treated patients. Chemotherapy was associated an 81% improvement in the BCSS rate (hazard ratio [HR] 0.19, CI 0.04-0.97, P = .046) and a 74% significantly improved OS rate (HR 0.26, CI -0.08-0.87, P = .029). Whereas receiving at least six cycles of chemotherapy was associated with improved RFS, stage III disease and the presence of lymphovascular invasion were associated with poorer RFS, BCSS, and OS outcomes.
This paper provides important information for to help guide treatment recommendations for the management of TNBC in older women.
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