medwireNews: A database analysis indicates that adjuvant chemotherapy may prolong overall survival (OS) in patients aged at least 70 years with node- and estrogen receptor (ER)-positive breast cancer and multiple comorbidities.
The researchers note, however, that there were significant differences in the baseline characteristics of patients who did versus those who did not receive chemotherapy “suggesting that physicians carefully selected patients likely to derive treatment benefit from adjuvant chemotherapy despite multiple comorbidities based on certain unmeasured variables.”
Therefore, “the results of this study should be interpreted with caution,” stress Nina Tamirisa, from The University of Texas MD Anderson Cancer Center in Houston, USA, and co-workers.
They identified 1592 patients aged 70 years and older from the US National Cancer Database who had received axillary surgery for node-positive, ER-positive, HER2-negative invasive breast cancer between 2010 and 2014. All patients had a Charlson/Deyo score of 2 or 3, indicating the presence of “severe comorbidities,” the authors explain in JAMA Oncology.
The 22.0% of patients who received adjuvant chemotherapy were significantly younger than the remaining 78.0% who did not receive chemotherapy (mean age, 74 vs 78 years) and were significantly more likely to receive other adjuvant treatments, such as radiotherapy (67.4 vs 43.5%) and endocrine therapy (88.3 vs 82.5%).
Chemotherapy-treated patients also had larger tumors (pT3/T4 in 20.6 vs 14.7%) and a greater pathologic node burden (pN3 in 21.4 vs 6.5%) than their counterparts not given chemotherapy.
Among the 592 patients matched for multiple variables including age, Charlson/Deyo comorbidity score, and pathologic T and N stages, no significant difference was observed in the median OS of patients who did and did not receive chemotherapy, at 78.9 and 62.7 months, respectively, after a median follow-up of 43.1 months.
However, after adjusting for other risk factors, receipt of chemotherapy was associated with a significantly reduced risk for death, at a hazard ratio (HR) of 0.67.
Other factors associated with improved OS were endocrine therapy and radiotherapy (HRs=0.47 and 0.61, respectively), while a Charlson/Deyo score of 3 versus 2 was a significant predictor of worse OS (HR=1.94), as was a higher pathologic T stage (pT4 vs pT1, HR=3.51) and N stage (pN4 vs pN1, HR=1.71).
Writing in an accompanying commentary, Laura Biganzoli (Hospital of Prato, Italy) and colleagues note that “[c]hronologic age alone does not fully capture the complexity of elderly patients with cancer.”
They highlight that “[i]n this group of patients, treatment considerations should be individualized based not only on prognostic tumor-related factors but also on the global health status of patients, which is crucial to determine life expectancy and treatment tolerance.”
Tamirisa et al echo this sentiment and call for prospective clinical trials with the aim of developing “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.”
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JAMA Oncol 2020; doi:10.1001/jamaoncol.2020.2388
JAMA Oncol 2020; doi:10.1001/jamaoncol.2020.2194