Correlation of macroscopic and histological characteristics in the regional lymph nodes of patients with rectal and sigmoidal adenocarcinoma.

BACKGROUND/AIMS: The number of involved lymph nodes is a relevant prognostic parameter which determines the duration of survival in patients with colonic and rectal adenocarcinoma. The purpose of this study was to establish a correlation between the macroscopic (size and consistency) and microscopic characteristics of the regional lymph nodes (type of involvement in tumor tissue, state of the capsule, adherence of the lymph nodes, etc.) in patients with colorectal carcinoma.

METHODOLOGY

In this prospective study, 46 patients with rectal and sigmoid adenocarcinoma were studied through randomized selection. From the resected specimens, a total of 736 lymph nodes were identified (average 15.66 per patient), with the precise location determined according to Enker and Philiphsken. The macroscopic and microscopic characteristics of each lymph node were identified. These lymph node findings were then distributed by means of the x2 test, while the interrelationship of lymph node characteristics was determined by factor analysis.

RESULTS

Within the group of "small" lymph nodes, 17.18% were malignant. Additionally, of all the malignant lymph nodes, 46.23% were less than 5 mm in diameter. Although the malignant lymph nodes were predominantly diffusely involved within the tumor tissue, 19.50% were focally involved within the tumor tissue, of which 48.38% were "small" lymph nodes, which are commonly non-palpable. Perforation of the capsule and adherence were more characteristic for focally mutated than for diffusely mutated lymph nodes in the cases of malignantly mutated lymph nodes.

CONCLUSION

Size and consistency of the lymph nodes are not dependable parameters for appraisal of lymph node involvement in tumor tissue, the state of the lymph node capsule, nor the interrelation among the lymph nodes. As in the case of the primary tumor, local tumor aggression in the lymph nodes is conditioned by the grade of differentiation, i.e. histologic immaturity, rather than by tumor size.