Risk factors for microscopically non-radical surgical resection in patients with rectal cancer
Valentinus Valdimarsson, Cecilia Dahlbäck, Pamela BuchwaldAbstract
Introduction
Achieving a microscopically radical (R0) resection is essential in rectal cancer surgery to reduce local recurrence, distant metastases, and improve long-term survival. This retrospective cohort study aimed to identify factors associated with microscopically nonradical (R1) rectal adenocarcinoma resection at a Swedish tertiary referral center.
Methods
Patients with rectal adenocarcinoma operated on between 2015 and 2021 at Skåne University Hospital were identified through the SCRCR and complementary chart review. Clinical, pathological, and perioperative variables were compared between R0 and R1 resections (circumferential resection margin (CRM) <0.1 mm) or involved longitudinal resection margin. Factors associated with R1 status were analyzed using univariable and multivariable regressions.
Results
Among 348 patients, 17 (4.9%) had an R1 resection. Distal tumor was strongly associated with R1 status: tumors ≤7 cm from the anal verge had an increased risk of non-radical excision (adjusted OR 3.77, 95% c.i. 1.23–14.2). Longer operating time was related to R1 resection in univariable analysis (median 531 versus 415 min, P = 0.045), but not after adjustment (OR 1.21, 95% c.i. 0.42–3.58). Advanced T stage (pT3–4) was associated with higher R1 risk (adjusted OR 4.15, 95% c.i. 1.06–27.7). In contrast, examination of over 22 lymph nodes was associated with a lower risk of R1 resection (adjusted OR 0.17, 95% c.i. 0.04–0.56).
Discussion
Distal tumors and advanced pathological tumor stage are key risk factors for R1 resection in rectal cancer, whereas an extensive lymph node yield appears protective. These findings support meticulous preoperative planning and tailored strategies for low rectal tumors to minimize the risk of R1 excision.