左、右侧大肠癌DNA含量、增殖活性及预后的差异研究

Differences in DNA Content, Proliferative Activity and Prognosis between Proximal and Distal Colorectal Cancers

目的：探讨左、右侧大肠癌之间可能存在的差异及其意义。方法：对８７例大肠腺癌标本（左侧５５例，右侧３２例）行流式细胞术及ＭＩＢ－１免疫组化检测，并对患者进行随访。结果：①左侧大肠癌异倍体多见（６９．０９％），而右侧大肠癌二倍体居多（７１．８８％）；②左侧大肠癌增殖活性显著高于右侧；③生存分析表明右侧大肠癌患者预后较左侧患者好。结论：左、右侧大肠癌ＤＮＡ含量、增殖活性、预后均存在显著差异，提示两者可能为不同的病理实体，其癌变机制可能不同。

Background/Aims: Epidemiological studies suggest that proximal and distal colorectal cancer (CRC) may be different. In this study, DNA content, proliferative activity and prognosis were compared in order to find out their differences and to elucidate their significances. Methods: Surgical specimens of 87 colorectal adenocarcinomas resected from 1989 to 1991, classified as proximal CRC (n=32) and distal CRC (n=55), were investigated by conventional histology, flow cytometry, and MIB-1 immunohistochemical staining, combining with their clinical features. The prognosis of those cases with complete follow-up data was studied. Results: DNA aneuploidy and diploidy were present in 69.09% and 30.91% of distal CRC, comparing with 28.12% and 71.88% of proximal CRC, respectively, (P<0.001), which implying a higher percentage of aneuploidy in distal CRC. S-phase fraction (SPF) was 24.93%±11.93% in distal CRC and 15.32%±7.71% in proximal CRC. MIB-1 proliferative index (PI) was 67.04%±25.29% in distal CRC, and 45.46%±20.86% in proximal CRC. These differences were statistically significant (P<0.0001) and that showed the proliferative activity in distal CRC was significantly higher than that in proximal CRC. Follow-up data were got from 73 cases (proximal, 26; distal, 47) and survival analysis showed that the prognosis of proximal CRC was better than that of distal CRC (P<0.05). Conclusions: The above results suggest that proximal and distal CRC are probably two distinct pathological entites and their carcinogenesis may be different.