Background: Some low-rectal cancers may spread into or recur in the inguinal lymph nodes despite optimal resection of the primary tumor. Hence, we hypothesized that lymphatic drainage of low-rectal malignancies may be inhomogeneous and that an extramesorectal route may be involved in at least some cases. The idea of our preliminary study was to analyze the potential lymphatic drainages in low-rectal cancer patients.
Methods: The first stage of the experiment included two consecutive low-rectal adenocarcinoma patients (free from inguinal lymph node metastases), in whom the lymphatics of the primary tumor were traced with Patentbalu dye. During the second stage the records of 206 consecutive low-rectal cancer patients were analyzed for presence of inguinal lymph node metastases.
Results: An evaluation of specimens from two rectal cancer patients revealed extramesorectal lymphatic drainage of the primary tumor besides the mesorectal route. An analysis of 206 patients revealed six cases of inguinal node metastases. Median age of patients was 55 years. They were all diagnosed with rectal adenocarcinoma, T3 or T4 tumors with G2 or G3 grade.
Conclusion: The demonstration of an alternative route of lymphatic drainage suggests that more radical surgical procedures are necessary for successful treatment of low-rectal cancers.