R. Amri1,2, L. G. Bordeianou1,2, P. Sylla1,2, D. L. Berger1,2 1Massachusetts General Hospital,General And Gastrointestinal Surgery,Boston, MA, USA 2Harvard Medical School,Surgery,Brookline, MA, USA
Introduction:
Tumor grade is one of the cardinal characteristics used in the surgical pathological assessment of a malignancy. High-grade disease invariably has a negative impact on the eventual outcomes of the concerned malignancy. We aimed to measure the magnitude of its influence as well as its stage-independent effect in colon cancer.
Methods:
All patients treated surgically at our center (2004 through 2011) with known disease grade were included in an institutional review board-approved database. We measured the relative risk (RR) of encountering distant and nodal spread of the disease in baseline pathology, as well as the risk of recurrence and overall and disease-specific mortality. In addition, a multivariate logistic regression adjusted for stage was used to assess the stage-adjusted odds ratio (OR).
Results:
A total of 961 patients with specified tumor grade were included for analysis. Of these, 191 (19.9%) patients had high-grade disease on baseline pathology. These patients were invariably at far higher risk of lymph node metastasis (63.7 vs. 38.2%; RR: 1.67) and metastatic presentation (30.9 vs. 15.3%; RR: 2.02) (both P<0.001). These baseline differences also led to a significantly higher risk of poor outcomes (all P<0.001), including disease recurrence (23.5 vs. 11.8%; RR: 1.99), overall mortality (56.5 vs. 31.8%; RR: 1.77) and colon cancer-specific mortality (34.6 vs. 16.6%; RR: 2.08). All of these findings were still statistically significant and within the same order of magnitude after adjusting of odds ratios for baseline staging in multivariate analysis.
Conclusion:
High-grade disease on baseline colon cancer surgical pathology is associated with a considerably higher rate of nodal and distant metastasis. As a result, the colon cancer-related mortality doubles for patients with high-grade disease. More interestingly, all of these findings were shown to be independent of baseline staging, confirming that high tumor grade is a stage-independent factor greatly influencing colon cancer outcomes and mortality.
