Published in:
01-04-2016 | Colorectal Cancer
Effect of High-Grade Disease on Outcomes of Surgically Treated Colon Cancer
Published in: Annals of Surgical Oncology | Issue 4/2016
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Introduction
Tumor grade is one of the cardinal pathological characteristics of colon cancer. Despite a large body of evidence on disease grade in general, the exact impact of high-grade disease in the context of the simplified high/low-grade dichotomy that is based on glandular formation rate has yet to be quantified.
Methods
Patients with sporadic colon cancer treated surgically at our center (2004–2011) were included in an institutional review board-approved database. We measured the rates of distant and nodal disease spread in baseline pathology and the multivariable hazard radio (mHR) of recurrence and overall- and disease-specific mortality.
Results
Among 922 patients with specified tumor grade in baseline surgical pathology, 175 (19.0 %) had high-grade disease. These patients were at far higher risk of lymph node metastasis (63.8 vs. 39.6 %; P < 0.001) and metastatic presentation (31.4 vs. 15.8 %; P < 0.001). These baseline differences also led to significantly worse outcomes, including disease recurrence (17.1 vs. 10.6 %; mHR = 1.83; P = 0.026), overall mortality (57.7 vs. 33.3 %; mHR = 1.65; P < 0.001), and colon cancer-specific mortality (39.4 vs. 16.9 %; mHR = 1.57; P = 0.004). Most significantly, in stage II patients (n = 294), those with high-grade disease (16.0 %) had an mHR of 2.84 (P < 0.001) for mortality.
Conclusions
High-grade disease on baseline surgical pathology is associated with a considerably higher rate of nodal and distant metastasis in colon cancer. As a result, the colon cancer-related mortality doubles for patients with high-grade disease. These findings were independent of baseline staging and confirm that the high-/low-grade tumor dichotomy is an important prognostic factor greatly influencing colon cancer outcomes across stages.