Metastases in locally advanced rectal cancer undergoing curatively intended treatment

The main cause of mortality in locally advanced rectal cancer (LARC) is metastatic progression. The aim of the present study was to describe frequency, pattern and outcome of metastatic disease in a cohort of LARC patients after curative resection. This was a single-centre cohort study of 628 LARC cases after neoadjuvant chemoradiotherapy/radiotherapy (CRT/RT) and surgery. Data, including the first site of metastasis, was registered in an institutional database linked to the National Cancer Registry. Metastases were diagnosed in 270 patients (43.0%) with liver and lungs as the first site in 113 and 96 cases, respectively. Involved resection margins, high tumour stage and poor response to CRT/RT were associated with metastasis development and inferior overall survival (OS). Metastasectomy was performed in 76 (67.3%) patients with liver metastases and 28 (29.2%) patients with lung metastases. Five-year OS was 89% in patients without metastases and 32% in metastatic cases. In patients selected for metastasectomy, 5-year OS was 69% and 53% for lung and liver metastases, respectively. Corresponding numbers without metastasectomy were 12% and 0%. In this large LARC cohort undergoing curatively intended treatment, liver and lung metastases occurred at similar frequencies. Liver as the first metastatic site was associated with inferior long-term outcome, while selection for metastasectomy was associated with better OS, with more than half of the resected patients being alive five years after LARC surgery. Our results show that the presence of resectable metastatic disease at diagnosis should not exclude a curative therapeutic approach in LARC.