Lymphatic invasion of little importance in colorectal cancer prognosis
MedWire News: Lymphatic invasion does not predict outcome in patients with node-positive colorectal cancer, Austrian researchers report.
"The invasion of tumour cells into vascular channels is a crucial step in the metastatic process," explain Cord Langner (Medical University of Graz) and colleagues.
"In colorectal cancer, lymphatic invasion has been significantly associated with the occurrence of lymph node metastasis and with poor outcome. However, the prognostic significance of lymphatic invasion is not clear in patients with tumours that have already spread to regional lymph nodes," they add.
To investigate, Langner and team retrospectively reviewed survival data for 168 patients with node-positive colorectal tumors (colon n=98; rectum n=70), and evaluated the prognostic significance of lymphatic invasion compared with that of other prognostic variables, such as tumor (T) and node (N) classification and tumor differentiation.
Lymphatic invasion, assessed by histopathology, was detected in 95 (57%) cases and was significantly associated with T and N classification and tumor differentiation, report the researchers in the Journal of Clinical Pathology.
During a mean follow-up period of 43 months, significantly more patients with lymphatic invasion experienced disease progression compared with those who had no lymphatic invasion (74 vs 60%). There were also more cancer-specific deaths among the patients with lymphatic invasion but the difference between the two groups was not statistically significant (60 vs 51%).
The researchers found that the prognostic significance of lymphatic invasion was influenced by tumor location. Specifically, when analysis was restricted to colon cancers, lymphatic invasion was significantly associated with progression-free and cancer-specific survival, whereas in rectal cancers no prognostic impact was observed.
Multivariable analysis, adjusted for age, gender, T and N classification, tumor grade, and lymphatic invasion showed that T4 (vs T1-3) and N2 (vs N1) status were independent predictors for progression-free survival, at hazard ratios (HRs) of 2.18 and 1.68, respectively.
Cancer specific death was independently associated with T4 status (HR=1.90), N2 status (HR=2.27), and poor tumor differentiation (grade 3 vs grade 1 or 2; HR=2.18).
By contrast, the team observed no significant independent influence on outcome for lymphatic invasion.
The researchers conclude that lymphatic invasion appears to be "of minor importance with respect to patient counseling and clinical decision-making."
"Only tumour and node classification, and tumour differentiation proved to be independent prognostic variables in node-positive colorectal cancer and [therefore] merit special attention in clinical decision-making."
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By Laura Cowen