[Reevaluation resection margin rectal cancer by flow cytometry and pathological examination].

OBJECTIVE

To investigate the appropriate distal resection margin in rectal cancer patients.

METHODS

Thirty specimens of rectal carcinoma with total mesorectal excision(TME) were studied by flow cytometry and pathological examination. The differences of DNA ploidy status, DNA index (DI), proliferative index (PI), S-phase fraction (SPF) among rectal cancer, 3 cm and 5 cm below the tumor, normal rectum, distal mesorectum 3 cm and 5 cm below the tumor, and normal colon mesentery were analysed by flow cytometry, and were compared with the data of pathological examination.

RESULTS

Pathological examination showed that there was no tumor invasion 3 cm and 5 cm below the tumor,but the metastasis rates of distal mesorectum 3 cm and 5 cm below the tumor were 26.7% and 6.7% respectively. The DI, PI and SPF of rectal cancer by flow cytometric examination were significantly higher than those of distal rectum 3 cm and 5 cm below the tumor, and normal rectum (P<0.05). The DI, PI and SPF of distal rectum 3 cm below the tumor were also significantly higher than those of distal rectum 5 cm below the tumor, and normal rectum (P<0.05), but there were no significant differences between DI, PI and SPF of distal rectum 5 cm below the tumor and those of normal rectum (P>0.05). The rate of DNA aneuploid of tumor was significantly higher than those of normal rectum and distal rectum 5 cm below the tumor,but there was no significant difference between the rate of DNA aneuploid of tumor and that of distal rectum 3 cm below the tumor. The DI and DNA aneuploid of rectal cancer and distal mesorectum 3 cm and 5 cm below the tumor were significantly higher than those of normal mesorectum,but there were no significant differences between DI and DNA aneuploid of rectal cancer and those of distal mesorectum 3 cm and 5 cm below the tumor. The PI and SPF of rectal cancer were significantly higher than those of normal mesorectum and distal mesorectum 3 cm and 5 cm below the tumor.

CONCLUSIONS

Rectal cancer is able to invade distal rectum 3 cm below the tumor and distal mesorectum 5 cm below the tumor, and radical resection of rectal cancer should beyond that range.