Revisiting the treatment strategy for rectal cancer through the pattern of local recurrence

Local recurrence after rectal cancer surgery is categorized as lymphatic spread (pelvic sidewall node (PSN)) and other types. This study aimed to investigate the risk factors associated with different patterns of local recurrence and to optimize the treatment strategy after rectal cancer surgery.

Patients with cStage I-III rectal cancer who underwent surgery at our institute were included in this study. Local recurrence was categorized as follows: (1) PSN recurrence and (2) "other" types of local recurrence. The risk factors associated with each type of recurrence (metastasis) were investigated.

A total of 212 patients with mid/low rectal cancer were included in this study (cStage I: 66; cStage II/III: 146). Additional treatment was employed in selected patients with high-risk features (n = 45; pelvic sidewall dissection: 18; preoperative chemo (radio)therapy: 37). Potential lateral node metastasis was significantly associated with PSN enlargement on imaging findings (no/yes, odds ratio (OR): 9.1; p = 0.007). The "other" local recurrence type was significantly associated with 3 different factors as follows: clinical circumferential resection margin (no/yes; OR: 18.0; p = 0.001), tumor histology (well and moderately/poorly differentiated, OR: 17.3; p = 0.008), and tumor diameter (p = 0.018). Among 146 cStage II/III patients, 66 (45.2%) who did not have any of the abovementioned 4 risk factors experienced no local recurrence even when no additional treatment was employed.

Risk factors may differ for different types of postoperative local recurrence patterns in rectal cancer. Recognizing these risk factors based on pretreatment findings can allow the optimization of treatment strategies for rectal cancer.