In older patients with multiple comorbidities and estrogen receptor (ER)-positive, node-positive breast cancer, chemotherapy improves survival, according to a study published today in JAMA Oncology.
"Breast cancer risk and the incidence of comorbidities increase with age. Treatment of elderly patients with significant comorbidities is challenging," write the investigators, led by first author Nina Tamirisa, MD, Assistant Professor of Breast Surgical Oncology at The University of Texas MD Anderson Cancer Center in Houston, Texas. "Because older patients with multiple comorbidities are often excluded from clinical trial participation, data are lacking on the survival benefit associated with adjuvant chemotherapy."
The retrospective cohort study included patients in the US National Cancer Database with ER-positive, human epidermal growth factor receptor 2 (HER2)-negative breast cancer who were aged 70 or older with a Charlson/Deyo comorbidity score of 2 or 3 and had undergone surgery for pathologic node-positive breast cancer between January 1, 2010, and December 31, 2014. The study's primary end point was the association of adjuvant chemotherapy with overall survival.
Of 2,445,870 patients in the dataset, 1,592 met the criteria and were included in the initial nonmatched analysis. Included patients had a mean age of 77.5 years, and 96.9% were female. Three hundred and fifty patients (22.0%) received chemotherapy, while 1,242 (78.0%) did not. Patients who received chemotherapy were generally younger (mean age of 74 vs 78 years) with larger primary tumors and a higher pathologic nodal burden. They were also more likely to receive additional adjuvant treatments, including endocrine therapy (88.3% vs 82.5%) and radiation (67.4% vs 43.5%).
In the nonmatched cohort, median follow-up was 41.4 months. Median overall survival for the entire group was 59.5 months, with increased survival for the patients who received chemotherapy compared with those who did not (78.9 vs 54.9 months). In the matched cohort, with a median follow-up of 43.1 months, there was no statistically significant difference in median overall survival between patients who did and did not receive chemotherapy (78.9 vs 62.7 months, P=0.13). However, after adjustment for potential confounding factors, chemotherapy was associated with improved survival, with a hazard ratio of 0.67 (P=0.02).
In the matched cohort, factors significantly associated with decreased overall survival included a Charlson/Deyo comorbidity score of 3 versus 2, higher pathologic T stage, and a higher pathologic N stage. Factors linked to improved survival included receipt of endocrine therapy and radiation therapy.
"To our knowledge, this was the first retrospective study to evaluate adjuvant chemotherapy outcomes in elderly patients with breast cancer and comorbidities," write Dr. Tamirisa and colleagues. "Our study found that carefully selected patients within this subset of the population may benefit from additional adjuvant treatment, highlighting the importance of accurately estimating life expectancy in patients with multiple comorbidities."
"Future studies should focus on integrating geriatricians into multidisciplinary breast cancer care to optimize outcomes in less well-studied older patients with multiple comorbidities and node-positive breast cancer," the investigators state. "Prospective clinical trials would inform the development of standardized tools to account for life expectancy, tolerance to treatment, and clinicopathologic tumor features for patients who might benefit from systemic therapy to optimize care in this underrepresented group of patients."
For More Information
Tamirisa N, Lin H, Shen Y, et al (2020). Association of chemotherapy with survival in elderly patients with multiple comorbidities and estrogen receptor–positive, node-positive breast cancer. JAMA Oncol. [Epub ahead of print] DOI:10.1001/jamaoncol.2020.2388Image credit: Min Yu. Courtesy of the National Cancer Institute / USC Norris Comprehensive Cancer Center