In all, 8372 women were diagnosed with early-stage ovarian carcinoma from 1988 to 2001. shows demographic and clinical characteristics of these women. Median age was 57 years with 66.6% 50 years of age or older. Across the three time intervals, 1988–1992, 1993–1997, and 1998–2001, there was an increase in the proportion of Hispanics and Asians diagnosed with early-stage cancers (P<0.001). More specifically, the proportion of Caucasians diagnosed with ovarian cancer decreased from 84.6 to 76.8 to 74.4%. Conversely, the proportion of Asians increased from 4.7 to 7.8 to 8.9% and the proportion of Hispanics increased from 4.8 to 7.6 to 8.5%. The number of patients that underwent lymphadenectomy has increased significantly from 26.2 to 38.7 to 54.2% over the study period (P<0.001). In all, 73.4% were categorised as stage I and 26.5% were categorised as stage II disease. There was no significant change in the proportion of cases, which were stage I or II over the three time periods (P=0.253). Histologically, 26.4% were serous, 26.6% endometrioid, 19.1% mucinous, 11.2% clear cell, and 16.6% were other epithelial cell types. An increase in the proportion of serous and endometrioid histology was seen in the latter time period, whereas there was a decrease in the mucinous subtype (P<0.001). A total of 20.3% of women had grade 1, 25.8% grade 2, and 26.5% had grade 3 disease. There was an increase in the percentage of grade 3 disease throughout the years (from 22.5 to 27.4 to 29.3%; P=0.010).
Demographic and clinicopathologic characteristics
For women who were younger than 50 years of age, 3-year survival was 93.1% compared with 84.2% for those who were 50 years old and older (P<0.001). Three-year disease-specific survival among Hispanics, Asians, Caucasians, and African Americans also differed (88.8 vs 89.4 vs 87.1 vs 84.5%) (P=0.005). Stage I patients had a significantly improved survival at 91.8% compared with 74.2% in those with stage II disease (P<0.001) (). Comparing the four major epithelial histologic cell types, endometrioid has a statistically significant increase in 3-year disease-specific survival compared with the other histologies as seen in and (P=0.015). Grade 1 tumours were found to have a higher 3-year disease-specific survival at 96.4% compared with grades 2 and 3, at 92.4 and 82.0%, respectively (P<0.001).
Kaplan–Meier disease-specific survival by stage (P<0.001).
Three-year disease-specific survival
Kaplan–Meier disease-specific survival by histology (P<0.001).
Over the 3 time intervals from 1988 to 1992, 1993 to 1997, and 1998 to 2001, women diagnosed with early-stage epithelial ovarian carcinoma had a marginal improvement in survival from 86.1 to 87.2 to 88.8% (P
=0.076) (). During these time periods, the 3-year survival was estimated based on age, race, surgery, lymphadenectomy, stage, histologic cell type, and grade of disease for each of the time periods (). Of note, there was a survival benefit in the women
50 years (P
=0.048), endometrioid histology (P
=0.015), and grade 3 disease (P
<0.001) over the three time periods. Although the use of lymphadenectomy has increased over time, of those patients who underwent staging procedures with lymphadenectomy, there was no improvement in survival over the three periods (from 93.2 to 93.5 to 93.1%; P
=0.978). A lack of significant improvement in disease-specific survival over the three time periods studied was also seen when separate analyses were performed for stage I and II patients with or without lymphadenectomy ().
Kaplan–Meier disease-specific survival by year (P=0.076).
In our multivariate model, year of diagnosis, younger age, surgery, earlier stage, nonclear cell histology, and lower grade were significant independent prognostic factors for improved survival (). However, after adjusting for surgical staging with lymphadenectomy, the year of diagnosis had a marginal significance (HR=0.99, CI: 0.97–1.00; P=0.098) (). The two multivariate models demonstrate the relationship between year of diagnosis and effect of surgical staging with lymphadenectomy.