Author: By Lynda Williams, Senior medwireNews Reporters
medwireNews: A study of older patients with advanced oestrogen receptor (ER)-positive breast cancer and multiple comorbidities indicates that adjuvant chemotherapy might extend overall survival (OS) in this population.
But the investigators also found that patients given chemotherapy were younger and fitter than those who were not, and were also more likely to receive radiotherapy and endocrine therapy, “suggesting that physicians carefully selected patients likely to derive treatment benefit from adjuvant chemotherapy despite multiple comorbidities based on certain unmeasured variables.”
Nina Tamirisa, from The University of Texas MD Anderson Cancer Center in Houston, USA, and co-authors therefore recommend in JAMA Oncology that “the results of this study should be interpreted with caution.”
The analysis included 1592 patients aged at least 70 years who were entered into the US National Cancer Database as having undergone surgery for pathological node-positive, ER-positive, HER2-negative breast cancer between 2010 and 2014. In all, 22% received adjuvant chemotherapy.
All of the patients had a Charlson/Deyo comorbidity score of 2–3 indicating “severe comorbidities” that would be expected to affect general health and “potentially limit life expectancy”, the researchers explain.
When a total of 592 patients were matched by age, comorbidity, facility type and location, pathological T and N stage, and use of radiotherapy and endocrine therapy, OS duration did not significantly differ between patients who did and did not receive adjuvant chemotherapy after a median 43.1 months of follow-up, at a median 78.9 versus 62.7 months.
However, after adjusting for other potential confounding factors in a multivariate analysis, the hazard ratio (HR) for death was a significant 0.67 favouring use of adjuvant chemotherapy, the authors report.
Poor OS in the matched cohort was significantly predicted by a comorbidity score of 3 versus 2 (HR=1.94) and a higher pathological T stage (pT4 vs pT1, HR=3.51) and N stage (pN3 vs pN1, HR=1.71), while better OS was associated with use of radiotherapy (HR=0.61) and endocrine therapy (HR=0.47).
The team emphasises that patients in the matched cohort who were given adjuvant chemotherapy were significantly younger than those who were not (average 74 vs 78 years) and had both larger tumours (pT3/T4 in 20.6 vs 14.7%) and a greater pathological node burden (stage pN3, 21.4 vs 6.5%). Patients given chemotherapy were also significantly more likely to receive radiation (67.4 vs 43.5%) and endocrine therapy (88.3 vs 82.5%).
Nina Tamirisa et al also note that the analysis was unable to determine the impact of luminal subtype on the effect of adjuvant chemotherapy and postulate that “genomic tests, such as Oncotype DX, may help to better capture tumor biology and refine patient selection for chemotherapy among those with node-positive disease.”
They conclude that “[p]rospective 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.”
Discussing the findings in an accompanying editorial, Laura Biganzoli, from the Hospital of Prato in Italy, and co-authors observe that “[o]lder adults are characterized by a unique framework of needs and may favor quality over quantity of life.”
Noting that the lack of quality of life information in the National Cancer Database prevented the study investigators assessing relevant endpoints other than survival, the editorialists recommend that “routine inclusion of quality-of-life measurements in large, nationwide databases should also be pursued, similar to what is now considered mandatory for prospective clinical trials.”
References
Tamirisa N, Lin H, Shen Y, et al. Association of chemotherapy with survival in elderly patients with multiple comorbidities and estrogen receptor-positive, node-positive breast cancer. JAMA Oncol; Advance online publication 16 July 2020. doi:10.1001/jamaoncol.2020.2388
Battisti NML, McCartney A, Biganzoli L. The conundrum of the association of chemotherapy with survival outcomes among elderly patients with curable luminal breast cancer. JAMA Oncol; Advance online publication 16 July 2020. doi:10.1001/jamaoncol.2020.2194
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