Rheumatoid factors in the sera of patient with gastrointestinal carcinoma.

One hundred and nineteen patients with gastrointestinal (GI) malignancy (80 colorectal, 25 gastric and 14 pancreatic carcinoma) were studied for rheumatoid factors (RF), antinuclear antibodies (ANA) and immunoglobulin levels and the findings correlated with size of tumor, stage of disease and survival. Twenty three (19.3%) of the patients were RF seropositive compared to 5.7% of 70 matched controls (P = 0.02). In two thirds of the seropositive patients RF were detected prior to the initiation of treatment. The proportion of RF seropositivity increased significantly in patients with tumors larger than 4 cm and in patients with Stage D disease. The authors found a high incidence of ANA in the patients: 32.4% compared to 8% in normal subjects (P less than 0.01), but the proportion of RF in this group was not significantly different. Survival distributions of the RF positive cases were different from that of the other patients (18 versus 25 months median survival); however, this was not statistically significant. These findings indicate that RF in GI cancer patients sera is not rare and can be related mainly to "tumor load," although not considerably affecting survival.