Surveillance for Posttransplant Malignancy
A comprehensive discussion of posttransplant malignancy been previously published on Medscape. It is clinically useful to separate cancers that are either unique to transplant recipients or whose incidence is increased many-fold from those that are not unique to transplant recipients or whose incidence is only slightly increased (ie, 1-3 fold). The former types generally are associated with viral infection, but there is no convincing evidence for viral pathogenesis in the latter. Cancers that occur with a much greater frequency than in the general population and are of particular interest to the kidney transplant service include carcinomas of the skin, cervix, and kidney; Kaposi's sarcoma; and lymphoma. In particular, patients at high risk for Kaposi's sarcoma (ie, of African or Middle Eastern descent) and those who are human herpes virus-8 antibody-positive should be closely monitored. Solid organ tumors that are commonly screened for in the transplant population but that are not greatly increased in the transplant population are breast, prostate, and colon cancer.
The United States Preventive Services Task Force (USPSTF), the leading independent panel of private-sector experts in prevention and primary care, recommends cervical cancer screening in the general population. Given the 2-fold to 5-fold increase in the cervical cancer incidence rate and associated increases in other regional cancers (vulvovaginal) in the kidney transplant population, screening makes sense.
The USPSTF does not make a recommendation for or against skin cancer screening, even in high-risk patients. Nonetheless, given the very high incidence burden and associated mortality and morbidity of skin cancer, especially in countries such as Australia (including squamous cell carcinoma increased > 20-fold, melanoma increased 5-fold, and Kaposi's sarcoma increased > 20-fold), it is difficult to defend not screening these patients. The issue then becomes who should perform the screening -- patient, nurse, transplant physician, family physician, or dermatologist -- and how often. In that regard, there is growing interest among dermatologists in the kidney transplant population. In light of recent developments with topical therapies, such as imiquimod 5% that is showing great promise in the treatment of actinic keratoses, superficial basal cell carcinoma, and squamous cell carcinoma in transplant recipients, early referral to a dermatologist (including pretransplant referral) may be beneficial. In addition, preventive strategies (ie, avoidance of sun exposure and use of sunscreen) should be strongly encouraged before and after transplantation.
There are no recommendations for lymphoma screening in the general population. However, posttransplant lymphoproliferative disorder (PTLD) is a significant problem in the transplant population. The benefit of prophylaxis with antiviral agents, avoiding donor Epstein-Barr virus (EBV)-positive to recipient EBV-negative transplantation, or screening EBV titers in the blood with immunosuppression lowering or other immune-based interventions have not been shown to be of benefit or widely practiced. The latter approach is still experimental. Neither routine screening with imaging studies nor physical examination in the asymptomatic patient has been studied or recommended. Screening and pre-emptive strategies are currently being tested.
Renal cell cancer is also a unique problem. The pathogenesis of renal cell cancer is unclear in this population, but it may be due to polycystic kidney disease or acquired cystic kidney disease. Renal cell cancer is increased in the transplant population more than 10-fold and may itself be the cause of the ESRD.[4,10] Screening in the pretransplant period should reduce the rate of early clinical presentation posttransplantation. However, there are no recommendations from the USPSTF or in the AST clinical practice guidelines to direct posttransplant surveillance.[10,19]
The common solid organ cancers (breast, colorectal, and prostate) that are screened for in the general population either are not convincingly increased or are increased by less than 2 fold. There is good evidence for colorectal and breast cancer screening in the general population. The USPSTF does not give an opinion for or against prostate or lung cancer screening. Most clinicians, however, recommend applying established standards developed for the general population to kidney transplant recipients, based on the rationale that evidence in the general population should be applied to kidney transplant recipients, transplant recipients are at greater cancer risk, and the costs associated with screening and early efficacious therapy should be comparable between the kidney transplant and general populations. Furthermore, it could be argued that it would be unethical to withhold a potentially life-saving strategy from an already vulnerable segment of the population.
Medscape Nephrology. 2005;2(2) © 2005 Medscape
Cite this: Screening and Early Detection: Cancer in the Kidney Transplant Recipient - Medscape - Dec 13, 2005.