Background
Testicular cancer is the second most common cancer in young men, diagnosed in about 750 Australian men each year, and has a very high cure rate.
However, testicular cancer patients treated with cisplatin-based chemotherapy or radiotherapy have an increased risk for cardiovascular disease (CVD), which might be related to the increased prevalence of the metabolic syndrome (MetS) in this group of patients.
Aim
The purpose of this cross-sectional Dutch study was to examine the relationship between MetS and CVD in three patient groups (surgery patients, carboplatin patients and combination-CT patients) and compare these against healthy controls.
Methods
This study assessed the prevalence of MetS and calculated the 10-year CVD risk in a cohort of 255 survivors of testicular germ cell tumours (GCT) originating in the testis (median age= 38.7 years) at a mean of 7.8 years after cancer treatment, compared with 360 healthy men.
The GCT survivors were recruited from a Clinical Oncology department between 2008 and 2010. Data for controls were obtained from GP health screening records (from 2009) in the same region.
79 patients had stage-I disease; 58 were treated with orchidectomy alone (‘surgery patients’) and 21 seminoma patients also received one adjuvant dose of carboplatin (AUC7; ‘carboplatin patients’).
Patients with disseminated disease (n=176) were treated with orchidectomy and combination chemotherapy (‘combination-CT patients’).
Prevalence of MetS was estimated from the National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III), 2002 (NCEP-ATPIII) criteria and International Diabetes Federation (IDF) risk score charts.
The 10-year cardiovascular risk profile was calculated using Framingham Risk Score (FRS) and the Systemic Coronary Risk Score (SCORE).
Results
There were no major differences in age between the different treatment groups of GCT survivors and the controls. BMI and waist circumference were comparable between the groups.
Smoking behaviour was comparable in all groups of patients and the controls, with about 40% smokers. There were no major differences in blood pressure and renal function between the groups.
Combination-CT patients had significantly higher fasting serum concentrations of cholesterol, LDL- cholesterol, and triglyceride than that in controls, and higher serum cholesterol and triglyceride concentrations compared with that in surgery patients.
Carboplatin patients had higher fasting serum cholesterol (P=0.04) and LDL-cholesterol (P=0.004) concentrations than that in healthy subjects. Survivors treated with surgery only had higher LDL-cholesterol concentrations than that in healthy subjects (P=0.04).
GCT survivors had an age-adjusted increased odds ratio (OR) for MetS (defined by NCEP-ATPIII) of 1.9 (95% CI=1.1 – 3.2) compared with that of healthy controls.
The risk for MetS was highest in GCT survivors treated with combination chemotherapy (OR=2.4, 95% CI=1.4 – 4.1). The risk of MetS was especially increased in survivors with testosterone levels in the lowest quartile (OR=2.5, 95% CI=1.3 – 4.7).
Ten-year cardiovascular risk as assessed by the FRS (3.0%) and SCORE (1.7%) algorithms was low, independent of treatment, and was comparable to controls.
Conclusion
Testicular germ cell tumour survivors have an increased prevalence of MetS, with hypogonadism and CT treatment being clear associated risk factors.
The increased prevalence of MetS was not associated with an increased 10-year cardiovascular risk. The researchers contend that because hypogonadism is associated with increased cardiovascular risk, GCT survivors should have a lower threshold for testosterone supplementation.
The researchers also advocate that guidelines to monitor blood pressure, lipid- and glucose metabolism, and assessment of gonadal hormone status should be introduced in international urology/oncology guidelines rather than focusing only on the detection of tumour recurrence, allowing for evidence-based counselling of GCT survivors regarding modifiable CVD risk factors.
