Gestational choriocarcinoma in norway, 1953-92 - an epidemiologic report

The objective of this study was to evaluate changes in incidence and survival rates in patients with gestational choriocarcinoma, and to examine the prognostic importance of clinical stage and age. A population based analysis (retrospective study) of all patients with gestational choriocarcinoma reported to the Cancer Registry of Norway in the 40-year period 1953-92. One hundred and fifteen patients with gestational choriocarcinoma were examined. The main outcome measures the incidence rates per 1,000 live births, clinical stage distribution (FIGO classification), 5-year survival rates (Kaplan-Meier plot) and relative rates (RR). The incidence rates ranged from 0.028 to 0.096, but no temporal trend was observed. Most cases were classified into the clinical stages I (53.9%) and III (24.3%). A more favourable stage distribution was seen in the diagnostic period 1973-92 compared to 1953-72 (p<0.01). The 5-year survival rate (Kaplan-Meier plot) rose from 57.9% in the first period to 94.8% in the last period (p<0.001). The survival rate declined gradually with advancing stage of the disease. The 5-year survival rates (1953-92) in the succeeding stages I, II, III and IV were 93.5%, 80.0%, 64.1% and 26.7%, respectively. The multivariate analysis (GLIM) revealed that stage was an important prognostic factor (p=0.00), whereas age did not reach the significant level as prognostic factor (p=0.72).