Characteristics and prognosis of colorectal cancer associated with rheumatic disease.

It is well known that host immunity plays an important role in the defense against colorectal cancer (CRC) progression. The effects of autoimmune diseases, such as rheumatic disease (RD) in which the immune system is deregulated, on this immunity have not been fully investigated. The medical records of 1299 consecutive patients diagnosed with primary colorectal cancer who underwent surgical resection were retrospectively reviewed. The clinicopathologic factors of 28 subjects with RD (RD group) were compared with those of 1271 patients without RD (non-RD group). Compared to the non-RD group, the RD group was typified by a predominance of females (P < 0.01), older age (P < 0.01), and a lower incidence of rectal cancer (P = 0.02). Although no difference was observed between the groups in terms of TNM classification, disease-free and overall survival were significantly poorer in the RD group in both univariate and multivariate analyses. Subjects who had RD for more than 10 years tended to have a higher frequency of lymph node metastasis (P = 0.06) and a significantly higher incidence of synchronous distant metastasis (P = 0.035) at the time of cancer diagnosis. RD was associated with a significantly poorer prognosis of colorectal cancer, suggesting that deregulation of the immune system by autoimmune diseases may adversely affect the host immune defense against colorectal cancer progression.