講演情報
[INTS5-5]Relationship between the location of initial tumors and the prevalences of metachronous tumors in colonoscopic surveillance
*Seiji Kimura1, Daisuke Nishiya1, Kazunori Satoh1, Hiroyuki Higuchi1 (1. Division of Gastroenterology and Endoscopy, Aomori Rousai Hospital, Japan)
Background and Aims: Recently it was reported initial right-sided adenoma may be a risk factor for colorectal cancer. The present study aimed to compare the cumulative incidences of metachronous lesions according to the locations of initial lesions during surveillance.
Methods: 2411 patients who underwent follow-up colonoscopies (median follow-up period 79.5 months, exam frequency 4.08 times) were classified according to the locations of initial lesions as follows; 1218 patients in whom initial lesions in the right or bilateral colon were resected (group A), and 1193 in whom initial lesions in the left colon only were resected (group B). They were sub-classified by initial findings as follows; 531 patients in group A1 and 420 in group B1 with diminutive adenomas, 378 in A2 and 279 in B2 with low-grade adenoma less than 10mm, 194 in A3 and 243 in B3 with high-grade adenoma or adenoma in size of 10-19 mm, and 115 in group A4 and 251 in B4 with TIS, T1 cancer, adenoma more than 20 mm in size, respectively. The cumulative incidences of metachronous index lesions (>10mm, villous, high-grade adenoma and/or cancer) were compared between group A and B using Kaplan-meier method.
Results: During follow-up the prevalences of index lesions were 16.0% in group A1, 17.1% in group B1, 19.6% in A2, 18.6% in B2, 23.7% in A3, 19.8% in B3, and 26.1% in A4, 24.3% in B4, respectively. There were no statistical differences between the prevalences of index lesions between any sub-groups in group A and B. Hazard ratios by logrank test between subgroups in group A and B were as follows; HR=0.94 (95%CI:0.68-1.29) N.S. ＜A1 vs B1＞, HR=0.99 (0.69-1.41) N.S. ＜A2 vs B2＞, HR=1.25 (0.85-1.86) N.S. ＜A3 vs B3＞, HR=1.16 (0.77-1.78) N.S. ＜A4 vs B4＞. Logrank test revealed no statistical differences between any sub-groups in group A and B. The prevaleces of metachronous invasive cancers were 1.4% in group A and 1.5% in group B with no statistical difference.
Conclusion: The comparison of cumulative incidences of metachronous index lesions between right-sided and left-sided initial lesions disclosed no significant difference.
Methods: 2411 patients who underwent follow-up colonoscopies (median follow-up period 79.5 months, exam frequency 4.08 times) were classified according to the locations of initial lesions as follows; 1218 patients in whom initial lesions in the right or bilateral colon were resected (group A), and 1193 in whom initial lesions in the left colon only were resected (group B). They were sub-classified by initial findings as follows; 531 patients in group A1 and 420 in group B1 with diminutive adenomas, 378 in A2 and 279 in B2 with low-grade adenoma less than 10mm, 194 in A3 and 243 in B3 with high-grade adenoma or adenoma in size of 10-19 mm, and 115 in group A4 and 251 in B4 with TIS, T1 cancer, adenoma more than 20 mm in size, respectively. The cumulative incidences of metachronous index lesions (>10mm, villous, high-grade adenoma and/or cancer) were compared between group A and B using Kaplan-meier method.
Results: During follow-up the prevalences of index lesions were 16.0% in group A1, 17.1% in group B1, 19.6% in A2, 18.6% in B2, 23.7% in A3, 19.8% in B3, and 26.1% in A4, 24.3% in B4, respectively. There were no statistical differences between the prevalences of index lesions between any sub-groups in group A and B. Hazard ratios by logrank test between subgroups in group A and B were as follows; HR=0.94 (95%CI:0.68-1.29) N.S. ＜A1 vs B1＞, HR=0.99 (0.69-1.41) N.S. ＜A2 vs B2＞, HR=1.25 (0.85-1.86) N.S. ＜A3 vs B3＞, HR=1.16 (0.77-1.78) N.S. ＜A4 vs B4＞. Logrank test revealed no statistical differences between any sub-groups in group A and B. The prevaleces of metachronous invasive cancers were 1.4% in group A and 1.5% in group B with no statistical difference.
Conclusion: The comparison of cumulative incidences of metachronous index lesions between right-sided and left-sided initial lesions disclosed no significant difference.