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Hemodynamic detection by transrectal ultrasound for evaluation of preoperative stage of rectal carcinoma

AIM: To investigate the relationship between the blood flow dynamics detected by transrectal ultrasound (TRUS) and the pathological stage of rectal cancer.

METHODS: A total of 240 patients with pathologically confirmed rectal cancer who underwent TRUS before operation were included. The hemodynamic parameters (PI, PSV, RI, and EDV) of the tumor were routinely detected. According to the pathological stage, the parameters were analyzed retrospectively and compared.

RESULTS: PI and RI decreased with the increase of the pathological stage, and EDV and PSV increased with the increase of the pathological stage. PI and RI were negatively correlated with pathology (r = -0.680, -0.470; P = 0.000, 0.000). PSV and EDV were positively correlated with pathology (r = 0.200, 0.289; P = 0.000, 0.000).

CONCLUSION: Detection of conventional arterial hemodynamic parameters (PI, PSV, RI, and EDV) can provide important and valuable information for clinical staging of rectal cancer.

Analysis on clinicopathological characteristics and prognosis of 576 patients with primary colorectal cancer

AIM: To analyze the clinicopathological characteristics of primary colorectal cancer and explore the influencing factors on the prognosis of patients.

METHODS: The clinical data of 576 patients with colorectal cancer diagnosed by colonoscopy during the past five years in the second affiliated hospital of Sun Yat-Sen University were analyzed retrospectively.

RESULTS: The occurrence rate of colorectal cancer was not significantly different between patients of different ages. The frequency of abdominal pain (χ² = 7.20, P < 0.05), the proportion of mucinous adenocarcinoma (χ² = 43.71, P < 0.05) and the rate of lymph node metastasis (χ² = 4.47, P < 0.05) in adolescent group were significantly higher than those in the mid-aged and aged one. The number of thin individuals was markedly higher in the aged group than that in the adolescent and mid-aged group (χ² = 9.64, P < 0.05). High differentiation was also observed in the aged patients (χ² = 8.06, P < 0.05). The overall 5-year survival rate was 61.79% (43.64%, 87.16% and 53.79% in the adolescent, mid-aged, and aged patients, respectively). The prognosis of colorectal cancer was associated with the age, tumor cell differentiation, lymph node metastasis, Dukes stages and the radical operation.

CONCLUSION: The frequency of abdominal pain, the malignant degree and the proportion of lymph node metastasis are the highest in the young patients. Age and Dukes staging are the independent factors correlated with the prognosis.

Clinical significance of carcinoembryonic antigen detection in rectal cancer patients with total mesorectal excision

AIM: To detect the carcinoembryonic antigen (CEA) in rectal cancer patients with total mesorectal excision (TME), and to prove the significance of TME in the treatment of rectal cancer.

METHODS: Pathological specimens were sellected from tissues of cancer, distal mesorectal margin (DMM), circumferential resection margin (CRM) and outer pelvic fascia in rectal cancer (n = 52) patients with TME. CEA was detected in these specimens using immunohistocheminical method, and the data were analyzed with SPSS software.

RESULTS: CEA expression was significantly higher in tissues of rectal cancer (47/52) than that in normal tissuess (2/20). There was significant difference between them (P < 0.001). CEA expression also existed in tissue of CRM (8/52). However, no CEA expression was observed in tissues of DMM and outer pelvic fascia.

CONCLUSION: CEA is highly expressed in tissues of rectal cancer. This provides scientific evidence for TME in the treatment of rectal cancer.

Expression of HLA molecule in colorectal cancer tissue

AIM: To study the relationship between the expression of HLA class I and clinicopathological significance in colorectal cancers.

METHODS: Expression of HLA class I and associated proteins was studied by immunohistochemistry in colorectal cancer, histologically normal mucosa adjacent to cancer (<3 cm), and histologically normal mucosa distant from cancer. Several monoclonal antibodies (mAbs) were used in this study: HC10 and HCA2 reacted with the nonmorphic determinant of heavy chain of HLA class I antigen; L368 reacted with ₂ microglobulin; SY1 reacted with LMP2 antigen, and TO-5 reacted with calnexin.

RESULTS: In colorectal cancer tissues, the expression of HLA -A,B/C, ₂M, LMP2 and calnexin were reduced compared to that of both in histologically normal mucosa adjacent to cancer and histologically normal mucosa distant from cancer (P = 0.001).The expression of calnexin in cancer was also reduced compared to that of both in histologically normal mucosa adjacent to cancer and histologically normal mucosa distant from cancer (P = 0.004). The expression of HLA-B/C antigen in cancer was associated with diverse groups of pathological stage. With increase in Dukes staging of the cancer, the expression of HLA-B/C downregulated, in which that in Dukes A was higher than that in Dukes D (P = 0.0262).

CONCLUSION: The expression of HLA class I and associated protein is downregulated in the colorectal cancer tissue. It may be one important mechanism by which colorectal cancer cell escapes immune surveillance.

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Anatomic pathology of tumor cell spread through lymph nodes in the mesorectum of rectal cancer

AIM: To investigate the size, distribution, and pattern of metastases and micrometastases of lymph nodes (LNs) within the mesorectum of rectal cancer.

METHODS: All rectal cancer specimens obtained by total mesorectal excision were treated with lymph node revealing solution to retrieve all LNs, which were detected with a combination use of haematoxylin and eosin staining and immunohistochemical (IHC) staining with an antibody against cytokeratin 20.

RESULTS: A total of 548 LNs in 31 specimens were harvested, with 17.7 nodes per case. 153 nodes (27.9%) in 27 patients (87.1%) were found positive by routine pathological examination and IHC staining. Of all the nodes retrieved, nodes <0.5 cm numbered 366 (66.8%) with 91 (59.5%) positive. Among the 27 metastasized cases, there were 15 cases whose tumors were located in the back wall of the rectum, in which 78 nodes were detected positive with 75 nodes along the superior rectal artery. In the other 12 cases with tumors positioned in the lateral wall, 75 nodes were diagnosed positive, with 37 nodes, 8 nodes around the branch of superior rectal artery and middle rectal artery on tumor side, and 9 nodes, 0 nodes on the opposite side, respectively.

CONCLUSION: The majority of tumor positive LNs in the mesorectum are <0.5 cm in diameter. LNs within the mesorectum are distributed mainly along major supplying vessels with around the superior rectal artery most. The pattern of lymphatic spread of rectal cancer has close relationships with tumor location in the rectal wall. Tumors in the posterior wall may spread in both sides of the mesorectum simultaneously, while tumors localized in one lateral wall tend to metastasize preferably to LNs in the mesorectum of tumor side.