Functional and oncologic outcomes in middle versus low locally advanced rectal cancer in the era of contemporary multimodal treatment

In this study, we aim to assess the impact of tumor height on surgical strategy, oncological outcomes, and long-term function in locally advanced rectal cancer. This retrospective cohort study included patients with cT3–T4 and/or N+ rectal cancer treated between 2017 and 2024. Tumors were classified as low locally advanced rectal cancer (LARC; 0 to < 5 cm) or middle locally advanced rectal cancer (MARC; ≥ 5 to < 10 cm). All patients underwent total mesorectal excision (TME) following multimodal therapy. Outcomes included perioperative variables, overall survival (OS), disease-free survival (DFS), and functional results assessed using Wexner, low anterior resection syndrome (LARS), the 36-Item Short-Form health survey (SF-36), and Five-Item International Index of Erectile Function (IIEF-5) scores. Predictors of permanent stoma were analyzed using multivariable regression. A total of 164 patients were included (MARC n = 84; LARC n = 80). Sphincter-sacrificing procedures were significantly more frequent in LARC (abdominoperineal resection [APR]: 48.8% versus 4.8%; p < 0.001), with a higher rate of permanent stoma. Positive margins were more common in LARC (26.3% versus 8.3%; p = 0.002). Despite these differences, OS and DFS were comparable between groups. Functional outcomes were globally impaired, with no difference in LARS severity, although continence was worse in LARC (Wexner: 9 versus 5; p = 0.03). In multivariable analysis, LARC (OR [odds ratio] 6.1; p < 0.001) and laparotomy (OR 8.6; p = 0.016) independently predicted permanent stoma. Tumor height strongly influences surgical strategy and the risk of permanent stoma, with low locally advanced rectal cancer (LARC) being associated with higher rates of sphincter-sacrificing procedures. Despite comparable oncological outcomes, functional impairment remains common in both groups. Importantly, anatomical sphincter preservation does not necessarily translate into preserved postoperative function, particularly in patients with low rectal tumors requiring extensive pelvic dissection.