Cardiovascular Morbidity in Testicular Cancer Survivors: Study of Risk Factors and Assessment of Pharmacogenomic Determinants of Toxicity

BACKGROUND:

Evidence has emerged that patients cured with cisplatin-bleomycin chemotherapy from disseminated testicular cancer (TC) develop a large number of cardiovascular risk factors (CRF) several years later. Recently, we observed an increased incidence of cardiac events 10-20 years after chemotherapy, possibly as a result of increased occurrence of CRF. Additional cardiovascular damage was observed after treatment: disturbed diastolic function of the left ventricle, microalbuminuria and increased endothelial damage parameters. Furthermore, a metabolic syndrome (syndrome X) with insulin-resistance, dyslipidemia, hypertension and endothelial damage was found in about one third of our cured patients. The investigators hypothesize that endothelial damage and metabolic changes caused by the bleomycin and cisplatin chemotherapy are the main causes for the observed increase in cardiovascular disease in these young cancer survivors. Genetic susceptibility may be an important determinant of individual risk of toxicity in individual patients.

PURPOSE:

1. To identify risk factors for cardiovascular disease (CVD) following testicular cancer.
2. To obtain insight into the pathway(s) of CVD development, by examining whether clinical CVD following testicular cancer is associated with a preceding unfavorable cardiovascular risk factor profile and/or with treatment-related factors.
3. To investigate genetic polymorphisms in pathogenetically important pathways that are potentially involved in the development of treatment related cardiovascular morbidity following testicular cancer.

PATIENTS AND METHODS:

Patients with non-seminomatous testicular cancer who have been uniformly treated with orchidectomy and cisplatin-bleomycin combination chemotherapy at the University Hospital Groningen, The Netherlands, since 1977 but before 2000 are eligible. 380 patients with non-seminomatous testicular cancer fulfill these criteria. A close routine follow-up of these patients after treatment has been done at the University Hospital Groningen. Clinical characteristics of these patients, treatment details including outcome and long-term follow-up are being registered systematically. From all patients who agree to participate assessment of their cardiovascular risk factors and the presence of subclinical cardiovascular damage will be performed by means of several measurement techniques. Also genomic DNA will be collected for studies on polymorphisms in pathogenetically important pathways. For the total cohort of patients several different late effects phenotypes of cardiovascular damage and cardiovascular risk factor patterns will be derived from the available data. These toxicity phenotypes will be used to select cases and controls from the total cohort to test candidate genetic polymorphisms on their association with occurrence of toxicity. The association of the different genetic polymorphisms with the toxicity phenotype will be estimated by comparing cases with different toxicity phenotypes with controls without that phenotype.

POSSIBLE RESULTS This research will provide insight into the pathogenesis of cardiovascular disease after treatment for testicular cancer. The main outcome will be the possibility to select individually those patients who are likely to have an increased risk to encounter specific cardiovascular toxicity during or after chemotherapy treatment for TC. This will provide opportunities for the tailoring of potential toxic treatment and/or guide primary and secondary prevention strategies for serious side effects of chemotherapy treatment.