Staging of rectal cancer and the pathologist's role in assessing the quality of rectal cancer surgery

For rectal cancer, local recurrence following surgical treatment is a grave complication that occurs in as many as 25% of cases. Pathological examination of the surgical resection specimen plays a primary role in assessing both the surgery- and tumor-related factors that contribute to the risk of recurrence. Tumor stage is considered the most accurate indicator of outcome in rectal cancer overall, but additional pathologic features that have been shown to have stage-independent prognostic significance include tumor grade; histologic type; extent of extramural penetration by tumor; neural, venous, and/or lymphatic invasion; tumor border configuration; and host lymphoid response. The most powerful predictor of local recurrence and overall outcome in rectal cancer, however, is the macroscopic quality of the mesorectum in the resection specimen and the proximity of the tumor to the circumferential (radial) resection margin.