Impact of treatment modality on clinical outcome in metastatic colorectal cancer patients stratified by metastatic sites

ABSTRACT

Objectives: To investigate the impact of location of metastases, and therapeutic modality on clinical outcomes in patients with metastatic colorectal cancer (CRC).

Methods: Data for metastatic CRC patients were sourced from the Surveillance, Epidemiology, and End Results (SEER) database (SEER ID: 15309-Nov2017). Patients were classified as follows: Group 1 patients had only liver metastasis; Group 2 patients had liver and lung metastasis; Group 3 patients had more than two metastasis sites. Patients were treated with surgery alone, radiation alone, or surgery plus radiation. The main study outcomes were (1) cancer-specific mortality and (2) survival benefit associated with treatment modality.

Results: A total number of 15,510 patients were included in this study. In Groups 1 and 2, patients treated with surgery plus radiation had a higher cumulative survival compared to other treatment groups (p-value <.001). Group 3 patients showed no significant difference in cumulative survival between the different treatment modalities (p-value = .218). Group 1 patients who received surgery plus radiation had a significantly lower risk of mortality compared to the other treatment groups (p-value <.001), and Group 2 patients who either received radiation treatment alone or surgery plus radiation had a significantly lower risk for mortality than patients who received other treatment modalities (p-value <.001). Multivariate analysis adjusting for known prognostic factors such as tumor sidedness and race did not alter the observed risk conferred by metastasis sites and treatment modalities.

Conclusion: Stratification by metastases sites, and by treatment modality can help multidisciplinary teams to reach a treatment consensus for metastatic CRC.

KEYWORDS:

• Colorectal cancer
• metastases
• surgical resection
• radiotherapy
• Surveillance Epidemiology End Results program (SEER)

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties. Peer reviewers on this manuscript have no relevant financial relationships to disclose.

Supplementary material

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Additional information

Funding

This manuscript was not funded.