ASCO 2011 abstract: A North American population-based outcome for early-stage ovarian clear cell (stages 1-11) carcinoma (OCCC). - ASCO 2011 (including w/wo irradiation)

Abstract:

Background: OCCC is regarded as having a poor outcome and being relatively treatment resistant. Recent Japanese data instead have demonstrated high survival in early stage and radiation sensitivity. This study was carried out to reproduce/refute these findings in a North American setting.

Methods: Women with OCCC who had attended one of the four British Columbia Cancer Agency (BCCA) centers have staging, pathological, treatment, and outcome data recorded in a computerized database. Irradiation (XRT) plus platin-based chemotherapy was the standard treatment. XRT usage mandated all such women provincially attending a BCCA centre. However, individual physicians within BCCA differed in their uptake of XRT. Outcomes with or without XRT could be compared. Univariate and multivariate (decision-tree analysis) analyses for disease-free survival (DFS) were performed.

Results: 241 Stage I-II women attended between January 2000 and December 2008 (IA/IB n=64; Ic n=147; II n=30). 5 year and 10 year DFS for stage IA/B; IC and II were 85 and 70%; 64 and 58%; and 43 and 43% respectively. IC subsets faired differently: rupture alone (spontaneous and surgical were equivalent) - 5 yr DFS 80% versus 34% if cytologically positive and 43% with surface involvement. Decision-tree analysis identified cytologic positivity as the most important factor (recurrence 27% if negative, 72% if positive). Surface involvement then further subdivided the cytologically positive: surface involved 93% recurrence, if not involved 60%. XRT had no effect in stage IA (85% DFS at 5 yrs with or without it) but was superior to chemotherapy alone in IC (5 yr DFS 68% vs 58%, 10 yr DFS 63% vs 52%, HR 0.59).
Conclusions: Stage IA OCCC has an excellent long-term outcome as does IC (rupture only). IC otherwise has a poor outcome as does stage II. XRT and chemotherapy improves outcome in stage IC versus chemotherapy alone.