RESUMEN
INTRODUCTION: The mitogen-activated protein kinase (MAPK) signalling network aberrations in metastatic colorectal cancer (mCRC) generate intrinsic dynamic effects and temporal variations that are crucial but often overlooked in clinical trial populations. Here, we investigate the time-varying impact of MAPK pathway mutation genotype on each treatment line's contribution to the overall clinical course. METHODS: The PROMETEO study focused on mCRC patients undergoing second-line treatment at 20 hospitals. We evaluated genotypes and employed flexible models to analyse the dynamic effect of each mutation. RESULTS: We examined data derived from 1160 patients. The effects of KRAS G12C or G12V, and BRAF V600E are clearly time-varying, with unexpected consequences such as the deleterious effect of BRAF V600E vs other genotypes dissipating over time when subjects receive antiangiogenics, or KRAS G12V and G12C showing increasing aggressiveness over time. Thus, contrary to expectations, the 12-month survival rate from the second line for those who survived >6 months was 49.9% (95% CI, 32.7-67.3) for KRAS G12C and 59% (95% CI, 38.5-80.6) for BRAF V600E. CONCLUSIONS: The dynamic perspective is essential for understanding the behaviour of tumours with specific genotypes, especially from the second line onward. This may be relevant in patient monitoring and treatment decision-making, particularly in cases with distinct mutations.
Asunto(s)
Neoplasias del Colon , Neoplasias Colorrectales , Humanos , Proteínas Proto-Oncogénicas B-raf/genética , Proteínas Proto-Oncogénicas p21(ras)/genética , Neoplasias Colorrectales/tratamiento farmacológico , Neoplasias Colorrectales/genética , Neoplasias Colorrectales/patología , Mutación , Neoplasias del Colon/genética , Progresión de la EnfermedadRESUMEN
PURPOSE: To describe the dosing patterns of regorafenib in a real-world population of patients with metastatic colorectal cancer (mCRC) in a routine clinical practice setting in Spain, focusing on the starting dose of regorafenib. METHODS: An observational, retrospective, multicenter study that included patients ≥ 18 years old who had histologically documented mCRC and who had initiated treatment with regorafenib since January 2017. Post hoc categorization of dosing patterns revealed the following: initial dose < 160 mg and dose escalation, initial dose < 160 mg and maintenance, initial dose equal to 160 mg and maintenance, and initial dose equal to 160 mg and dose reduction. RESULTS: Most patients (152/241, 63.8%) initiated treatment with regorafenib at doses < 160 mg. There was large variation in the starting dose of regorafenib over time: in 2017, most patients (59%) initiated regorafenib at a dose of 160 mg, this proportion decreased to 6% in 2021. There were no significant differences in the median progression-free survival according to the regorafenib dose patterns during the first two cycles. The proportion of patients who reported at least one adverse event (AE), had a grade 3-4 AE or had an AE leading to dose reduction was greater in the group of patients who received an initial dose equal to 160 and reduction. CONCLUSIONS: Our results indicate that physicians in Spain have gradually adopted a dose-escalation approach during cycle 1, which is a common practice for starting treatment with a reduced dose (< 160 mg/day), a strategy that seems to improve tolerability while maintaining efficacy. TRIAL REGISTRATION: Not applicable.