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.
Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: I.A.F: Grant to institution: DoMore Diagnostics. F.H.B: Payment to institution from Personal Genome Diagnostics. G.R.V: Grants to institution and/or nonfinancial support: BMS, Merck, Servier, Personal Genome Diagnostics, Bayer, Sirtex, Pierre Fabre, Lilly, Delfi Diagnostics, Nordic all financial supports transferred to the institute. A.M.M and W.M.U.G: declare no potential conflicts of interests. M.K: advisory role: Eisai, Nordic Farma, Merck-Serono, Pierre Fabre, Servier. Institutional scientific grants: Bayer, Bristol Myers Squibb, Merck, Personal Genome Diagnostics (PGDx), Pierre Fabre, Roche, Sirtex, Servier. Non-financial interests: chair of the ESMO RWD-DH working group, co- chair: DCCG, PI PLCRC (national observational cohort study), involved in several clinical trials as PI or co-investigator in CRC. J.M.L.R: institutional financial interests: Bayer, BMS, Merck-Serono, Pierre Fabre, Servier, HUB 4 organoids, Cleara Biotech.
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