Prognostic factors affecting the survival of operated patients with colorectal cancer: significance of delayed hypersensitivity skin reactions and nutritional status.

We examined whether an immune status measured with a series of delayed hypersensitivity skin reactions was associated with the survival of colorectal cancer patients. Clinical, laboratory and pathological data and various anthropometric parameters were prospectively measured in a series of 100 Greek patients diagnosed with colorectal cancer between 1987-1989 and followed up to mortality until 31 December 1992. The Kaplan-Meier method and Cox's Proportional Hazards Regression Model were used for the survival analysis. Age and stage of the disease were the most powerful predictors of survival. Other factors associated with survival of patients were various indices of nutritional status, tumour marker CEA, erythrocyte sedimentation rate and haematocrit. Immune status was statistically significantly related to survival, with anergic patients having a threefold risk of mortality compared to immunocompetent patients. Mortality risk decreased with the increasing number of positive hypersensitivity reactions (relative risk = 0.72; 95% confidence intervals 0.52-1.00), after adjustment for age, sex, stage and body mass index. Similar but attenuated results were obtained when analyses were limited to patients without a disseminated disease. These findings indicate that immune status is significantly associated with the stage of the disease; patients with advanced stages have a lower immune response. The immune response may be an important factor for the survival of cancer patients irrespective of the stage of the disease.