Background: Because the risk of developing malignant tumors after heart transplantation is approximately 100-fold higher, methods for rapid diagnosis must be developed to allow early and aggressive treatment in these patients. Although tumor markers have been used frequently for surveying already detected cancer, we studied their value in screening for tumors in heart transplant patients.
Methods: The levels of the tumor markers CEA, CA19-9, CA125, CA72-4, TPA, TPS, and CYFRA 21-1 were determined prospectively in 3-month intervals in 91 heart transplant patients between 1993 and 1998.
Results: In eight patients a definite diagnosis of cancer was made during the marker survey (mean observation time 2.85 +/- 1.3 years), including bronchogenic carcinoma in six, renal carcinoma in one, and colon cancer in one. All patients with bronchogenic carcinoma were smokers. The markers had a sensitivity below 60% to detect cancer. Given a 2-fold cutoff level (10 ng/mL), the CEA was the only marker with sufficient specificity (93.8%, only one false-positive result). Two patients were symptom-free even though they had elevated CEA levels. In one of those patients, disseminated intractable cancer was diagnosed at first evaluation, whereas no tumor was found in the other case at first evaluation. Subsequently, by means of fluorodeoxyglucose positron emission tomography, a hypermetabolic region was found in the right upper mediastinum. Control computed tomographic scan 4 weeks after the first investigation showed disseminated intractable disease also in this patient. Another heart transplant patient with colon cancer showed a normalization of the CEA after hemicolectomy and an increase in the CEA when liver dissemination developed. There was a relationship between cardiac death and CA125 and TPS in some heart transplant patients.
Conclusions: We conclude that the CEA is the only tumor marker with adequate sensitivity and specificity to detect subclinical malignancies in the follow-up of heart transplant patients. However, because of several limitations (limited diagnostic and therapeutic possibilities and enormous costs), we cannot recommend screening by tumor markers on a regular basis. Because of the elevated risk of cancer in patients who had organ transplantation, further prophylactic measures, especially smoking cessation programs, must be developed. Once a malignancy is diagnosed, tumor markers can help target clinical decisions. Additionally, nonspecific increases in CA125 and TPS levels might be related to nonmalignant circulatory disturbances and cardiac death.