Baseline predictors of early treatment failure in patients with Platinum Resistant/ Refractory (PRR) and Potentially Platinum Sensitive (PPS) recurrent ovarian cancer (ROC) receiving ≥3 lines of chemotherapy- The Gynaecologic Cancer Intergroup (GCIG) Symptom Benefit Study (SBS) (#203)
Background. Women with PRR/PPS ROC are a heterogeneous group with unpredictable response to palliative chemotherapy (PC). GCIG SBS recently completed recruitment of 949 patients treated with PC. Primary aim was to validate an instrument to measure symptom benefit. The secondary aim was to identify factors that predict early progression. 25% of patients with PRR-ROC received <8 weeks of PC.
Methods. Physicians recorded baseline characteristics, symptoms (symptomatic ascites, cramping abdominal pain), site/ extent of disease and pre-specified lab values. Association between baseline characteristics and progression-free survival (PFS) was assessed using time-to-event methods. Median PFS was calculated according to clinically relevant categories and log-rank test was applied to assess prognostic value. Cox regression was used to compute hazard ratios and 95% CI to assess the effect of variables on PFS.
Results. Sufficient follow-up for analysis of PFS was available in 791 patients. Median PFS and overall survival was 4.3 months (95% CI, 3.9-4.9) and 12.9 months (95% CI, 11.4-14.0) respectively. In univariate analysis, PFS was statistically significant associated with these factors- haemoglobin, PRR-ROC, ascites, abdominal cramps, nodal disease, thrombocytosis, CA125 >1000, LDH >600, ECOG status, and elevated C-reactive protein. The following factors were not significantly associated with PFS - visceral metastases, albumin <25 g/L, lymphocytes <0.5x10 9/L and tumour volume. Significant variables in multivariable analysis included: ECOG ≥2 (HR 1.61; 95% CI, 1.18-2.19; p=0.003); nodal disease (HR 1.37; 95%CI, 1.13-1.67; p=0.002); ascites (HR 1.54; 95%CI, 1.24-1.92; p=0.0001); platinum resistant versus sensitive (HR 1.39; 95%CI, 1.12-1.72; p=0.002); CA125 >1000 (HR 1.35; 95%CI, 1.09-1.67; p=0.005) and LDH >600 (HR 1.88; 95%CI, 1.36-2.60; p=0.0001).
Conclusion. A number of simple variables predict which patients progress rapidly. These results will be used to construct prognostic models to aid clinical decisions and trial stratification in patients with platinum resistant/ refractory and potentially platinum sensitive recurrent ovarian cancer.