Choosing the right strategy based on individualized treatment effect predictions: combination versus sequential chemotherapy in patients with metastatic colorectal cancer

Clinical outcomes of intensive versus less intensive first-line chemotherapy for metastatic colorectal cancer

Aims: Physicians determine the treatment regimen for metastatic colorectal cancer on a case-by-case bases, according to the individual disease characteristics. We retrospectively compared the baseline characteristics and efficacies of first-line treatment among patients with metastatic colorectal cancer who received intensive therapy involving fluoropyrimidine plus oxaliplatin and/or irinotecan, potentially with molecularly targeted agents as well, versus less intensive fluoropyrimidine and/or bevacizumab therapy. Materials & methods: Data were collected from a medical claims database. The efficacy outcomes were: time to treatment failure, time to first subsequent therapy and overall survival. Results: The less intensive therapy group (n = 633) had higher median age, lower daily activity levels and shorter time to treatment failure, time to first subsequent therapy and overall survival than the intensive therapy group (n = 3829). Combination therapy with molecularly targeted agents and bevacizumab improved treatment efficacy outcomes in the intensive and less intensive groups, respectively. Conclusion: Patient age and daily activity levels were important factors for determining treatment intensity.

Time-varying prognostic value of primary tumor sidedness in metastatic colorectal cancer: A population-based study and meta-analysis

We studied the prognostic value of primary tumor sidedness in metastatic colorectal cancer over time and across treatment lines. Population data on synchronous metastatic colorectal cancer patients were extracted from the Netherlands Cancer Registry and SEER database. Pubmed, EMBASE and Cochrane library were searched for prospective studies on metastatic colorectal cancer to conduct a meta-analysis. Inclusion criteria consisted of metastatic disease, systemic treatment with palliative intent and specification of primary tumor location. Data were pooled using a random-effects model. For the population-based data, multivariable Cox models were constructed. The Grambsch-Therneau test was conducted to evaluate the potential time-varying nature of sidedness. Meta-regression incorporating treatment-line as variable was conducted to test the pre-specified hypothesis that the prognostic value of sidedness varies over time. Analysis of 12 885 and 16 160 synchronous metastatic colorectal cancer patients registered in the Netherlands Cancer Registry and SEER database, respectively, indicated a time-varying prognostic value of sidedness (P < .01). Thirty-one studies were selected for the meta-analysis (9558 patients for overall survival analysis). Pooled univariable hazard ratio_{left-sided/right-sided} for overall survival was 0.71 (95% CI: 0.65-0.76) in 1st-line, 0.76 (0.54-1.06) in 2nd-line and 1.01 (0.86-1.19) in 3rd-line studies. Hazard ratios were significantly influenced by treatment line (P = .035). The prognostic value of sidedness of the primary tumor in metastatic colorectal cancer patients treated with palliative systemic therapy decreases over time since diagnosis, suggesting that sidedness may not be a useful stratification factor in late-line trials. This decrease in prognostic value should be taken into account when providing prognostic information to patients.

Personalizing First-Line Systemic Therapy in Metastatic Colorectal Cancer: Is There a Role for Initial Low-Intensity Therapy in 2021 and Beyond? A Perspective From Members of the Australasian Gastrointestinal Trials Group

Palliative chemotherapy is the cornerstone of treatment for the majority of patients with metastatic colorectal cancer, with the aim of increasing length and quality of life. Although guidelines outline the available treatment options in the first line, they provide limited guidance on choice and intensity of the chemotherapy backbone. Data from the TRIBE and TRIBE2 studies confirm a survival benefit with triplet FOLFOXIRI and bevacizumab, and this is a preferred option for younger patients with good performance status able to tolerate it. However, the relative benefit of a fluoropyrimidine doublet with oxaliplatin or irinotecan over single-agent fluoropyrimidine with or without a biologic is less certain; the available data demonstrate that single-agent fluoropyrimidine plus a biologic with planned sequencing of subsequent agents can produce similar overall survival outcomes with reduced toxicity. Our analysis of local real-world registry data suggests that this is an underutilized approach, particularly in younger and fitter patients. Established prognostic factors, including patient age, performance status, tumor sidedness, and biomarkers such as RAS/BRAF, are key in treatment selection; patients with left-sided RAS/BRAF wild-type disease or patients with low tumor bulk may be ideal for a less intensive regimen. Further studies are required to confirm the value of less-intensive regimens in the modern era, where the incorporation of biologic therapies has become routine and where non-chemotherapy options are emerging as viable options for molecularly defined patient subsets.