CAPOX Toxicity Common in CRC Patients

TOPLINE:

Less than half of patients with localized colorectal cancer completed their planned capecitabine and oxaliplatin (CAPOX) chemotherapy cycles, with female patients showing particularly poor tolerability. Grade ≥ 3 adverse events affected nearly a third of patients.

METHODOLOGY:

• Previous studies indicate that capecitabine exhibits less favorable tolerability among patients with colorectal cancer in the United States, with women facing an increased risk for toxicity.
• Researchers conducted a single-institution retrospective study of 153 patients with stage II (21.6%) or III (78.4%) colorectal cancer receiving neoadjuvant or adjuvant CAPOX between June 2017 and June 2023.
• The primary outcome measure focused on completion rate of intended CAPOX cycles, determined through chart review, regardless of dose levels.
• Secondary outcomes included rate of grade ≥ 3 adverse events, hospital admission rates, and dose reductions.
• Analysis included patients aged ≥ 18 years who received at least one cycle of CAPOX, with treatment completion defined as receipt of all intended cycles regardless of dose levels.

TAKEAWAY:

• Overall completion rate of intended CAPOX cycles was 44.4% (95% CI, 36%-52%), with significantly lower rates among female patients at 34.6% (95% CI, 23%-45%).
• Multivariable analysis identified female sex (odds ratio [OR], 0.408; 95% CI, 0.197-0.845; P = .016), White race (OR, 0.38; 95% CI, 0.14-0.99; P = .047), and six or more planned cycles (OR, 0.379; 95% CI, 0.181-0.793; P = .010) as independent predictors for early discontinuation.
• Grade ≥ 3 adverse events occurred in 30.7% (95% CI, 23%-38%) of patients, with hospitalization due to CAPOX-related toxicity affecting 17.6% (95% CI, 11%-23%) of the cohort.
• Treatment completion rates varied by intended cycle number, with 55.20% (95% CI, 43%-66%) completing four cycles vs 33.33% (95% CI, 20%-45%) completing eight cycles.

IN PRACTICE:

“This study highlights that a substantial number of patients with localized CRC undergoing curative-intent treatment with CAPOX do not complete the planned cycles of chemotherapy because of toxicity…These findings underscore the need for careful patient selection and appropriate supportive care to optimize the therapeutic benefit of CAPOX in this setting,” wrote the authors of the study.

SOURCE:

The study was led by Veronica Mears, PharmD, University Hospitals Cleveland Medical Center in Cleveland, Ohio. It was published online on March 4 in JCO Oncology Practice.

LIMITATIONS:

According to the authors, the study faced inherent limitations of retrospective studies, including potential incomplete data capture and lack of information on social determinants of health. The institution lacked in-house dihydropyrimidine dehydrogenase genotype testing during the study period, making it impossible to determine if DPYD variants contributed to toxicity. Additionally, many patients completed their therapy shortly before data collection began, preventing analysis of dose density impact on survival. While the single-institution nature of the study may limit generalizability, the inclusion of patients from multiple centers across both academic and community settings partially mitigates this limitation.

DISCLOSURES:

Mears disclosed stock and other ownership interests in Vanguard Funds and a consulting role with Medsphere. Additional disclosures are noted in the original article.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.