Prognostic factors for survival in stage IV rectal cancer: A Swedish nationwide case-control study

The aim was to identify patient-, tumor- and treatment-related prognostic factors for five-year survival in rectal cancer patients with synchronous stage IV disease.

This nationwide case-control study was based on the Swedish Colorectal Cancer Registry with supplementary information from medical records and the Swedish Inpatient Registry during the period 2000-2008. All resected rectal cancer patients with synchronous metastases that survived more than five years were included as cases. The control group consisted of corresponding patients who lived less than five years, matched in a 1:2 based on gender, age, resection of the rectal tumor, and the study period.

A total of 405 patients were identified; 99 long-term survivors (LTS) and 182 short-term survivors (STS). Patient-related factors of symptoms and comorbidity did not differ between LTS and STS. Among the treatment-related factors, multiple site metastases (p = 0.007), bilobar liver metastasis (p = 0.002), and increasing number of liver metastasis (p < 0.001) were associated with STS. Prognostic treatment-related factors were preoperative radiotherapy (p = 0.001), metastasectomy (p < 0.001), and radical resection of the primary tumor (p = 0.014). In the multivariable analysis, the single most important factor for becoming a LTS was a metastasectomy (hazard ratio: 8.474, 95% confidence interval: 4.098-17.543).

The most important prognostic factor for long-term survival in patients with stage IV rectal cancer was metastasectomy, especially liver surgery. With thorough selection of patients for metastasectomy more patients with metastasized rectal cancer may survive beyond five years.