Risk and location of cancer in patients with preoperative colitis-associated dysplasia undergoing proctocolectomy.

Objective: To evaluate the influence of preoperative dysplasia grade, appearance, and site on risk and location of cancer in patients with colitis. Background: The ability to predict the presence and location of cancer in colitis patients with dysplasia is essential to facilitate recommendations regarding the necessity and type of surgery. Methods: Ulcerative and indeterminate colitis patients who underwent proctocolectomy for dysplasia were retrospectively selected. Patient characteristics and findings at colonoscopic surveillance were associated with findings on the surgical specimen by regression analysis. Results: From 1984 to 2007, 348 proctocolectomy specimens with preoperative dysplasia showed cancer in 51 (15%) and dysplasia in 172 (49%) cases. Patients with preoperative high-grade dysplasia (HGD) had cancer in 29% compared with 3% in low-grade dysplasia (LGD) (P < 0.001). Patients with preoperative dysplasia-associated lesion/mass (DALM) had cancer in 25% compared with 8% in flat dysplasia (P < 0.001). In LGD with DALM, the risk of cancer was not significantly higher than in flat LGD (7% vs 2%, P = 0.3), but risk of cancer or HGD was higher with a threefold increase (29% vs 9%, P = 0.015). On multivariate analysis, HGD, DALM, and disease duration were independent risk factors for postoperative cancer. In patients with isolated colonic dysplasia above the sigmoid level, postoperative rectal involvement was limited. Conclusions: Risk of cancer for patients with HGD or DALM is substantial. Despite low risk of cancer in patients with flat LGD, threshold for surgery should be low given the high prevalence of postoperative pathologic findings. Only in selected cases, colonoscopic surveillance after discussion of associated risks may be acceptable, provided high patient compliance can be assured. Surgery should be considered in all other cases, because it is the only modality that can eliminate the risk of cancer. The location of preoperative dysplasia may allow for the clarification of the need for proctectomy especially in the poor risk surgical patient.