Purpose: This study was designed to evaluate the frequency of microscopic distal intramural spread in rectal adenocarcinoma and its correlation to other histopathologic prognostic factors.
Methods: We examined 55 patients with adenocarcinomas of the lower one-third of the rectum and measured the extent of distal intramural spread in the submucosa and/or muscular layer in comparison with Dukes Stage, diameter of tumor, distance of distal margin of resection from tumor, depth of infiltration into perirectal adipose tissue, nodal status, neoplastic infiltration of lymphatic vessels, blood vessels, and nervous branches.
Results: Distal intramural spread was found in 40 percent of patients, 77 percent of whom had advanced tumors with nodal metastases. Distal intramural spread appeared to be strictly related to tumor size (superior to 40 mm), infiltration of the perirectal adipose tissue, multiple positive lymph nodes, presence of neoplastic emboli in the intramural lymphatic vessels, and neoplastic invasion of the nervous branches. Local recurrence occurred in one Dukes Stage B patient with a positive distal margin of resection and in four patients with a negative distal margin of resection: three Dukes Stage C and one Dukes Stage B patients with neoplastic involvement of the circumferential margin of resection of the mesorectum.
Conclusion: These preliminary data suggest that distal intramural spread may carry little importance in determining local recurrence of rectal adenocarcinoma.