Abstract
BACKGROUND: The rate of locally recurrent rectal cancer (LRRC) in Norway has decreased due to advancements in surgical techniques and preoperative treatments. Despite this, LRRC continues to present significant morbidity and mortality challenges. This study aims to analyze survival outcomes following different treatment modalities for LRRC in Norway and assess the impact of changes in treatment strategies over time. METHODS: This retrospective study utilized data from the Cancer Registry of Norway, focusing on patients with stage I-III primary rectal cancer treated between 1997 and 2016, who subsequently developed LRRC. Treatment modalities, including surgery, radiotherapy (RT), and re-irradiation (reRT), were analyzed, and the impact of various factors on overall survival (OS) was assessed. RESULTS: Of the 13,480 patients who underwent surgery for rectal cancer, 827 (6.1%) developed LRRC. For all patients, the median survival from LRRC diagnosis was 18 months, with a 3-year OS of 29%. For patients who underwent surgical resection of LRRC, the 3-year OS was 55% for those who received pre-operative RT, 50% for those who received reRT, and 35% for those without any radiation therapy. For non-operated patients, 3-year OS rates were 22% with RT, 21% with reRT, and 15% for patients without radiation therapy. Patients diagnosed after 2006, patients with early-stage primary cancer, younger age (<75), extended recurrence interval, or well-differentiated tumors had better survival outcomes. INTERPRETATION: This study describes the outcomes after multimodal treatment approaches for LRRC on a national level over a 20-year period. Patients who underwent surgical resection combined with RT or reRT had the best survival outcomes; however, this group represents a highly selected patient population.