Survival and Patient-reported Outcomes of Real-world High-risk Stage II and Stage III Colon Cancer Patients After Reduction of Adjuvant CAPOX Duration from 6 to 3 Months

Aim: Adjuvant chemotherapy has been advised for high-risk stage II and III colon cancer since 2004. After the IDEA study showed no clinically relevant difference in outcome, reduction of adjuvant CAPOX duration from 6 to 3 months was rapidly adopted in the Dutch treatment guideline in 2017. This study investigates the real-world impact of the guideline change on overall survival (OS) and patient-reported outcomes (PROs).

Methods: Patients with high-risk stage II (pT4 +) and III (pN+) colon cancer were selected from the Netherlands Cancer Registry, based on surgical resection and adjuvant CAPOX before (2015-2016) versus after (2018-2019) the guideline change. Both groups were compared on OS, using multivariable Cox regression, and on PROs.

Results: Patients treated before (n = 2330) and after (n = 2108) the guideline change showed similar OS (HR 1.02; 95 %CI [0.89-1.16]), also in high-risk stage III (pT4/N2, HR 1.06 [0.89-1.26]). After the guideline change, 90 % of patients were treated for 3 months with no inferior OS to those still receiving 6 months (HR 0.89 [0.66-1.20]). PROs 2 years after CAPOX completion, available for a subset of patients, suggest a lower neuropathy (n = 366; 26.2 [21.3-31.1] to 16.5 [14.4-18.6]) and better quality of life (n = 396; 80.9 [78.6-83.2] to 83.9 [82.8-84.9]), but no significant difference in workability (n = 120; 31.5 [27.9-35.1]) to 35.3 [33.8-36.7]), with reduction from 6 to 3 months of CAPOX.

Conclusion: This real-world study confirmed that shorter adjuvant CAPOX did not compromise OS and may improve PROs, complementing the IDEA study and supporting 3 months of adjuvant CAPOX in daily clinical practice.