High grade, synchronous colon cancers after renal transplantation: were immunosuppressive drugs to blame?

Recipients of renal transplants are known to have an increased incidence of cancer, which is believed to be related to the use of immunosuppressive drugs used to prevent rejection. Although the risks of lymphoma and Kaposi's sarcoma are clearly increased in this setting, the association with colon cancer is controversial. We report a 44-yr-old woman, 20 yr post-renal transplant, and with no family history of colorectal cancer or polyps, who was found to have synchronous, poorly differentiated colon cancers associated with extensive abdominal lymph node, bone marrow, and bone (skull) metastasis. The long term immunosuppressive drugs that she had received may have been an important factor in her tumor development and/or progression. Our case and literature review suggest a possible mild, increased risk of colon cancer development in patients after renal transplantation.