Trend of Clinicopathologic Characteristics of Colorectal Cancer in Asan Medical Center: a 15-Year Experience

PURPOSE: A retrospective study was performed to provide an overview of changes over time by age, stage, tumor location, and surgical therapy of colorectal cancer over the past 15 years. METHODS: We analyzed the cases 6,314 colorectal cancer patients who underwent surgery at Asan Medical Center between January 1990 and December 2004. The period was divided into three periods: 1990 to 1994, 1995 to 1999, and 2000 to 2004. We analyzed trends over time for stage, resectability, and demographic factors of colorectal cancer over the past 15 years. RESULTS: The mean age of the patients in the periods from 1990 to 1994, from 1995 to 1999, and from 2000 to 2004 were 57.1 (21~89), 57.4 (14~91), and 58.9 (15~91) years, respectively, showing an increasing tendency over time (P<0.001). The male-to-female ratios were 1.2 : 1, 1.3 : 1, and 1.6 : 1, repectively, and this male preponderance has been more marked in recent years (P=0.003). There was no change in tumor location over time. The ratios of early cancer to advanced cancer were 0.06 : 1, 0.09 : 1, and 0.11 : 1, respecfively, showing an increasing tendency over time (P=0.002). The curative resection rate increased over time (P<0.001). The non-curative resection rate was higher and the non-resected rate was lower in the period 2000 to 2004 than in the period 1990 to 1999 (P<0.001). The ratios of the lowest anterior resection to the abdominoperineal resection were 0.06 : 1, 0.49 : 1, and 1.02 : 1, respectively. With decreasing tendency of abdominoperineal resection, the lowest anterior resection rate has increased gradually over time (P<0.001). CONCLUSIONS: Etiologic studies are necessary to understand the male preponderance in colorectal cancer, and multi-center studies should be conducted to understand the changing trend of colorectal cancer in Korea.

Effect of Biofeedback Treatment in Patients with Fecal Incontinence

PURPOSE: We aimed to assess the efficacy of biofeedback therapy for patients with fecal incontinence (FI) according to the etiology. METHODS: Twenty-nine patients with fecal incontinence were treated with biofeedback therapy using a EMG-based system. The efficacy was assessed by using changes in the FI score (Cleveland Clinic, Florida: 0~20) and satisfaction based on a subjective evaluation score from 0 to 100. The median follow up duration was 12 (3~25) months. RESULTS: Ten patients had idiopathic fecal incontinence. Fourteen patients had fecal incontinence due to a sphincter saving operation for rectal cancer. Four cases had spinal cord injury and one patient had a major external sphincter tearing due to trauma. The mean age was 52 (16~78) years. The median number of biofeedback sessions was 10 (3~15) overall. The mean efficacy was 42.8%, and the mean satisfaction score was 56.6. Improvements in the FI score and in the patients' satisfaction varied according to the etiology, 69.5% and 71.5 in the idiopathic group, 28.5% and 49.3 in the postoperative group, and 35% and 24 in the spinal cord injury group. In the idiopathic group, 50% of the patients showed an improvement in the FI score of more than 75%, and 90% of the patients showed an improvement of more than 50%. The number of liquid incontinence episodes was improved 78.3% later in the biofeedback group, and this result was much better than in the postoperative incontinence group (31.8%, p=0.03). CONCLUSIONS: The success rate of the biofeedback therapy for fecal incontinence is acceptable. Subjective satisfaction is relatively higher than the improvement in the ecal incontinence score. Idiopathic fecal incontinence may be the best indication for biofeedback therapy.

Outcome of Curative Resection in Patients with Completely Obstructing Colorectal Cancer

PURPOSE: A large bowel obstruction as a result of primary colorectal cancer has a poor outcome. A retrospective study was designed to verify the recurrence patterns and to determine the prognostic factors after a curative resection in patients with a completely obstructing colorectal cancer. METHODS: Eight hundred patients with stage II and III colorectal adenocarcinomas (37 patients with a complete obstruction and 763 patients without an obstruction) underwent curative surgery between 1989 and 1996 at the Asan Medical Center. The median follow-up period was 55 (3~107) months. RESULTS: Clinicopathologic variables, i.e. sex, serum carcinoembryonic antigen (CEA), Borrmann type, differentiation, and tumor stage in the two groups were similar. Patients with obstructing colorectal cancer were significantly older than those without an obstruction (61+/-14 vs. 56+/-12 years, P=0.02). Rectal cancers were more frequent in the non-obstructing cancers than in the obstructing cancers (P=0.02). The recurrence rate in the two groups was similar (obstructing vs. non-obstructing cancer, 27.0% vs. 28.0%). Ten patients with 12 recurrences were identified in 37 obstructing colorectal cancer patients, three with local recurrences (8.1%) and nine with distant metastasis (24.3%). The 5-year survival rate between the same stages was not different between the two groups (77.8% vs. 85.3% in stage II, 65.1% vs. 60.4% in stage III). Among the various clinicopathologic variables, neural invasion was strongly associated with a poor prognosis in obstructing colorectal cancer on multivariate analysis (P<0.05). CONCLUSION: Because the obstructing cancers and the non-obstructing colorectal cancers had a similar outcome, curative surgery appears to offer the best chance of a cure in stage II and III obstructing colorectal cancer.

Reappraisal of AJCC Staging System in Colorectal Cancer

PURPOSE: The TNM classification for carcinoma of the colon and the rectum provides more detail than other staging systems. This study was performed to evaluate the effectiveness of AJCC staging system (5th ed., 1997) for the colorectal cancer in predicting prognosis. METHODS: We analyzed a data base of 1,233 colorectal cancer patients (M:F=673:560) who underwent surgery in Asan Medical Center during July 1989-December 1996. Survival analysis was performed between the stages and the subgroups in same stage by using Kaplan-Meier method and log rank test. Borderline subgroup comparison between the stages was performed, also. Significance was assigned to a P value of <0.05. RESULTS: Mean age of the patients was 57 (19-90) years old. Median follow-up period was 42 (6-129) months. The number of patients in each stage were 0: 15, I: 152, II: 390, III: 465, IV: 199. The 5 year overall & disease free survival rates of each stage were 100%, 100% (in stage 0), 96.4%, 93.6% (in stage I), 82.7%, 82.2% (in stage II), 59.9%, 55.3% (in stage III), and 7.3%, 24.9% (in stage IV), respectively (P=0.000). Subgroup analysis in stage I (T1N0 vs. T2N0) and II (T3N0 vs. T4N0) revealed no differences. However, in stage III, N1 (n=246) group showed better survival than N2 (n=219) group (70.3%, 65.5% vs. 49.2%, 44.6%: P=0.000). Borderline survival analysis between stage I and II (T2N0 vs. T3N0) was significantly different (96.6%, 95.7% vs 82.7%, 82.3%: P=0.006). However, between stage II and III (T4N0 vs. T1N1), appropriate analysis was impossible due to small number of cases. CONCLUSIONS: AJCC staging system for colorectal cancer was reliable and effective in predicting prognosis. However, substages are needed in stage III.