Anal Cancer Risk Higher in Solid Organ Recipients
Transpl Int. 2007;20:497-504
Recipients of solid organ transplants have a higher rate of anal cancer, but not colorectal cancer, than the general population, according to an Austrian study.
In addition, researchers found that post-transplant lymphoproliferative disorders (PTLD) may involve the colon.
Felix Aigner, MD, of
Anal neoplasias were observed in four patients (0.11%). By comparison, the incidence in the general population is 0.002%, the investi-gators noted. PTLD developed in 50 recipients (1.4%), of whom five presented with intestinal involvement at a mean 3.8 years after transplantation. Colorectal cancer developed in nine patients (0.25%), an incidence similar to that of the general population (0.30%).
Dr. Aigner's group observed that viruses have a major role in the pathogenesis of the common malignancies in solid organ recipients. The most important pathogens are human papillomavirus (HPV), Ep-stein-Barr virus (EBV), human herpes virus 8, and hepatitis B and C viruses. Some of these pathogens may cause malignancies of the colon, rectum, or anus.
Based on their findings, the authors concluded that post-transplant screening for viral infections, particularly HPV and EBV, and concomitant anogenital lesions such as cervical intraepithelial neoplasia and anal intraepithelial neoplasia, should be integrated into routine examinations of solid organ recipients.
In addition, they wrote that “any nonspecific gastrointestinal symptom such as bleeding, protein-losing enteropathy, and weight loss in immunosuppressed patients should alert the clinician to the possibility of gastrointestinal PTLD, which demands colonoscopic evaluation.”
The investigators suggested that once malignancies have developed following transplantation, switching the immunosuppressive regimen from calcineurin inhibitors to mTOR inhibitors—which seem to possess an antitumor effect—may be a promising strategy.