Prognostic impact of early oxaliplatin discontinuation in colon cancer unravelled

A pooled analysis of 11 adjuvant trials showed that early treatment discontinuation (ETD) in patients with stage 3 colon cancer receiving 6 months of chemotherapy led to a reduced disease-free survival (DFS) and overall survival (OS). In contrast, early oxaliplatin discontinuation (EOD) was not associated with decreased DFS or OS if the patients had received at least 50% of the oxaliplatin cycles [1].

Dr Claire Gallois (Université de Paris, France) explained that approximately 30% of the patients with localised colon cancer discontinue their 6-month prescribed adjuvant chemotherapy early. “However, robust data on the prognostic impact of ETD or EOD is lacking.” Therefore, the current study assessed the factors associated with ETD and EOD. Moreover, the study evaluated the prognostic impact of ETD and EOD on DFS and OS. Patients were classified as ETD or EOD if they received less than 75% of the prescribed cycles of chemotherapy (i.e. FOLFOX or CAPOX) or oxaliplatin, respectively. Assessed were 10,444 patients with stage 3 colon cancer undergoing a 6-month, oxaliplatin-based chemotherapy.

ETD was experienced by 20.9% of the patients and EOD was experienced by 18.8% of the patients. Women, older patients (≥65 years), patients with an ECOG PS ≥1, and patients following a CAPOX regimen had a significantly higher risk of ETD or EOD (P<0.001). Also, patients with a BMI of <18.5 had an increased risk of ETD (P<0.001).

ETD resulted in a significant reduction in DFS: 3-year DFS rates were 69.0% vs 78.8% for ETD and non-ETD (HR 1.61; P<0.001). The 3-year OS rates show a similar result (74.7% vs 84.7%; HR 1.73; P<0.001). The result was consistent across subgroups, except for the low-risk cancer group treated with CAPOX. In contrast, EOD did not result in decreased 3-year DFS rates (EOD 77.2% vs no-EOD 78.3%; HR 1.07; P=0.28) or 3-year OS rates. This result was consistent across pre-defined strata. Notably, patients who received <50% of their oxaliplatin cycles had a decreased 3-year DFS rate compared with patients who did not discontinue oxaliplatin (74.1% vs 78.3%; HR 1.35; P=0.018). This association was not observed for patients who received ≥50% of their oxaliplatin cycles (3-year DFS rate 78.1%).

Dr Gallois concluded that it seems important to maintain the planned number of treatment cycles in this population. However, patients with grade 1­–2 neurotoxicity may discontinue oxaliplatin after 3 months, without impairing clinical outcomes.

1. Gallois C, et al. Prognostic impact of early discontinuation of treatment and oxaliplatin in patients treated with 6 months of oxaliplatin-based chemotherapy for stage 3 colon cancer: an ACCENT/IDEA pooled analysis of 11 adjuvant trials. Abstract 11, ASCO GI 2022, 20–22 January.

 

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Posted on 21 March, 202221 March, 2022