Effects of Chronic Immunosuppression on Long-term Oncologic Outcomes for Colorectal Cancer Patients Undergoing Surgery

Abstract

The effects of chronic immunosuppressive therapy (CIST) on long-term oncologic outcomes for patients who undergo surgery for colorectal cancer are not known. We investigate whether CIST affects these outcomes. From a prospective colorectal cancer database, patients undergoing colorectal resection for cancer between 1996 and 2005 and on CIST (steroids and/or cyclosporine, azathioprine, 6-mercaptopurine, FK-506, methotrexate) were identified and compared with a control group matched for age(±5 year), gender, type, and year (±2 year) of operation; American Society of Anesthesiology score; cancer stage; differentiation; vascular invasion; blood transfusion; and postoperative adjuvant therapy. The groups were compared for early and long-term outcomes. Cox models produced hazard ratios and Wald P values to assess associations between survival and the presence of immunosuppressive treatment. Fifty-five (20 female and 35 male) patients were on CIST for inflammatory disease, transplantation, chronic obstructive lung disease, other cancers, and hypopituitarism. Both groups were comparable for the matched characteristics. Chronic immunosuppressive therapy and control groups had similar overall postoperative morbidity (36.4% vs 27.3%, P = 0.3) and wound infection rates (14.5% vs 5.5%, P = 0.13). Chronic immunosuppressive therapy group had significantly lower 3- and 5-year overall (49.1% vs 76.3%, and 45.1% vs 66.2%, respectively, P = 0.003) and disease-free survival (45.5% vs 69.1%, and 41.7% vs 63.3%, respectively, P = 0.005) than the control group. Local recurrence was similar between groups. Patients on chronic immunosuppression tolerate colorectal cancer resection but have significantly worse long-term oncologic outcomes.These findings need careful consideration when evaluating the relative roles of the various treatment modalities for this group of patients presenting with colorectal cancer.