BACKGROUND

To identify baseline rectal MRI characteristics that may serve as predictive factors for recurrence in patients with rectal adenocarcinoma after surgical resection.

METHODS

This retrospective, single-center study included 269 consecutive patients (median age, 55 years [interquartile range, 47-65]; 144 men and 125 women) diagnosed with rectal cancer from January 2015-December 2017 who underwent baseline rectal MRI followed by surgical resection. MRI characteristics were collected from rectal MRI synoptic reports. Recurrence-free survival was defined as the time between surgical resection and recurrence (local recurrence and/or metastatic disease) or death. Statistical analysis included Cox proportional hazards to determine associations between baseline rectal MRI/clinical characteristics and recurrence.

RESULTS

The median recurrence-free survival in the study sample was 6.4 years. Baseline rectal MRI characteristics associated with recurrence at univariable analysis were: age > 55 years (P = 0.044), low rectal tumor location (P = 0.04), craniocaudal length ≥ 5.0 cm (P = 0.007), anal canal involvement (P = 0.011), presence of suspicious total mesorectal excision (TME) lymph nodes > 0.5 cm (P = 0.03), mesorectal fascia involvement (P = 0.04), T3 stage (P = 0.024), T4 stage (P = 0.008), and M1 stage (P = 0.024). At multivariable analysis, only age > 55 years (P = 0.012) and the presence of suspicious TME lymph nodes > 0.5 cm (P = 0.049) remained associated with recurrence.

CONCLUSION

Advanced age and the presence of suspicious TME adenopathy > 0.5 cm on baseline rectal MRI are associated with higher risk of recurrent disease in patients with resected rectal cancer.