Introduction Non-platinum chemotherapy agents are often given in platinum-resistant/refractory recurrent ovarian cancer (PRROC) treatment. This large cohort study aimed to compare the effectiveness between pegylated liposomal doxorubicin (PLD) and gemcitabine, which are 2 most common second-line chemotherapy agents in Thailand.

Methods All epithelial ovarian cancer (EOC) patients treated at two tertiary cancer centers during 2009–2018 were enrolled. PRROC patients were included and their treatments were reviewed. The effectiveness of PLD and gemcitabine was compared using the treatment-effect model.

Results Of 1,708 EOC patients, 954 patients developed recurrence and 530 patients (55.6%) diagnosed as PRROC. The most common second-line chemotherapy regimen was PLD (251 patients, 47.4%), followed by gemcitabine (217 patients, 40.1%), and other (62 patients, 12.5%). After applying the treatment effect model by Inverse Probability Weighting with Regression Adjustment (IPWRA), the median time of disease progression after treatment with PLD, and gemcitabine was 6.3 months (5.4 to 7.1), and 6.7 months (5.2 to 8.2), respectively. The average treatment effect (ATE) or the difference of median time of disease progression between both agents was not statistically significant. Whereas the median time from PRROC diagnosis until death after treatment with PLD and gemcitabine was 22.5 months (17.7 to 27.4), and 17.6 months (15.0 to 20.3), respectively. The ATE indicated that PLD had 4.9 months (-0.5 to 10.4) longer than gemcitabine, although there was no statistical significance.

Conclusion/Implications PLD and gemcitabine had comparable effectiveness for PRROC treatment. The median time from PRROC diagnosis until death after treatment with PLD tended to be 4.9 months longer than gemcitabine.