AMSTERDAM – Low-grade toxicity resulted in modification of chemotherapy regimens for nearly one in five older cancer patients and discontinuation of treatment in one in ten, judging from findings from a recent study.
"This is a quite clinically meaningful finding in a large, but understudied patient group," Dr. Tania Kalsi said at the multidisciplinary European cancer congresses.
More than half of cancer diagnoses occur in patients older than 65 years, and this heterogeneous group is growing in size with the aging world population.
Dr. Kalsi reported on a subsample of 108 patients treated with chemotherapy who were part of a prospective, cohort of 516 patients, aged 65 years and older, receiving any cancer treatment at the chemotherapy day unit in a tertiary referral hospital in London. All patients completed the Comprehensive Geriatric Assessment screening questionnaire to evaluate their comorbidities, functional status, and quality of life.
Their mean age was 72 years (range 65-86), 51% were male, and 59.3% were receiving chemotherapy with a palliative intent. Cancers were colorectal in 33, gynecologic in 18, upper gastrointestinal in 16, lung in 15, and other in 26. On average, 4.2 cycles of chemotherapy were delivered.
Of the 108 patients studied, 66 (55.5%) required modification of their chemotherapy regimen due to toxicity, and 21 of them (19.4%) had toxicity of grade 2 or lower, said Dr. Kalsi, a geriatric oncology research fellow at Guy’s and St. Thomas’ NHS Foundation Trust, London.
The mean number of grade 2 toxicities resulting in treatment modification was 2.19; seven patients who needed treatment modification had only one grade 2 toxicity.
Dose modifications were most commonly triggered by fatigue and hematologic toxicity (eight patients each), gastrointestinal (six patients), and infections (five patients), she said.
In univariate analysis, no significant association was seen between low- vs. high-grade toxicity treatment modifications and performance status (P = .730), treatment intent (P = .978), and patient age (less than 75 years vs. at least 75 years; P = .47).
"This is really one of the first studies to look at the impact of low-grade toxicity in older people"
Low-grade toxicity, however, triggered treatment modifications significantly more often in patients with multiple comorbidities (four or more) vs. fewer comorbidities (24.4% vs. 58%; P = .011), Dr. Kalsi said.
Although the series involved few patients, this finding is particularly interesting, said Dr. Riccardo Audisio of the University of Liverpool, U.K., who featured the study (Ab. 1555) in a highlights session at the meeting.
Overall, 23 patients (21.2%) stopped chemotherapy early due to toxicity, and nine (8.3%) of these patients had no toxicity above grade 2.
An average of 1.78 grade 2 toxicities prompted treatment discontinuation and 3 patients had only one grade 2 toxicity. The same culprits of fatigue (5 patients) and hematological toxicity (4 patients) caused early discontinuation, Dr. Kalsi said.
Univariate analysis found no significant association between low- vs. high-grade toxicity treatment discontinuation and performance status (P = 1.00), treatment intent (P = .657), patient age (P = .417), or comorbidities (P = .657), although the small sample size may have influenced the analyses, she said.
"This is really one of the first studies to look at the impact of low-grade toxicity in older people" and "highlights some key questions around clinical decision making" Dr. Kalsi said. Future research will need to tease out whether low-grade toxicity truly has a greater clinical impact on older people or whether there are differences in the clinical interaction between doctors and older patients. For example, is there a lower threshold for modifying/discontinuing treatment in older people; do older people report their symptoms differently than younger patients; and would additional support from a geriatrician liaison improve treatment tolerance; she asked.
Dr. Kalsi reported no relevant conflicts of interest.