Pathologic prognostic factors in the recurrence of rectal cancer.

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. Among the tumor-related factors, stage has long been considered the single most accurate indicator of survival. However, recent evidence strongly suggests that the most powerful predictor of both local recurrence and overall outcome in the absence of distant metastatic disease is the macroscopic quality of the mesorectum in the resection specimen and the proximity of the tumor to the circumferential (radial) resection margin. Additional pathologic features have been shown to have stage-independent prognostic significance in colorectal cancer and may help to further define risk of adverse outcome. Such features include: tumor grade; histologic type; extent of extramural penetration by tumor; neural, venous, and/or lymphatic invasion; tumor border configuration; tumor budding; and host lymphoid response. The predictive value of tumor-specific molecular features is currently under investigation and may help to further improve prognostication and refine individual patient management in rectal cancer.