Compliance to clinical guidelines for early-stage epithelial ovarian cancer in relation to patient outcome.

Objectives: To assess compliance to current surgical staging and adjuvant treatment guidelines for patients with early-stage epithelial ovarian carcinoma and its impact on overall survival.

Methods: Patients diagnosed between 1991 and 1997 with early-stage ovarian cancer were recruited from the Regional Cancer Registry of the central region in the Netherlands. Demographic data, tumour characteristics, surgical findings and therapeutic data were abstracted from medical records. Patients were classified into optimal and non-optimal surgical staging. Overall survival was estimated using Kaplan-Meier method. To adjust for age hazard ratios for overall survival were estimated with a Cox Proportional Hazards model.

Results: One hundred and twenty-five patients were included in the study, 41 of them (32.8%) were optimally staged. Guidelines for adjuvant radio- or chemotherapy were adequately followed in all 62 grade I patients and in 44 out of 59 grade II and III patients (74.6%). During 734.6 person-years of follow up 31 patients died. Five-year overall survival figures were 97.6% in the optimally staged group and 68.5% in the non-optimally staged group. Patients who were non-optimally staged, had a significant higher risk to die than those who were optimally staged (HR: 7.4; 95% CI: 1.7-32.2). In patients with a grade II and III tumours, complete surgical staging still had a significant influence on survival (HR: 3.8; 95% CI 1.7-8.3). In women with grade II or III tumours, adjuvant radio- or chemotherapy administered in accordance to the guidelines did not improve overall survival regardless whether they were optimally staged or not.

Conclusion: Incomplete staging in early-stage ovarian cancer leads to gross mis-classification in grade II and III tumours and to a lesser extent in grade I tumours. This leads to undertreatment in both surgical and adjuvant therapy. Subsequently unnecessary deaths may occur. More effort must be put in identifying obstacles interfering with compliance of guidelines.