Patients are randomly assigned to receive lower-dose decitabine treatment followed by TC regimen (ie, DTC arm).

Patients were randomly assigned to receive carboplatin plus paclitaxel (ie, TC arm).

Patients in DTC arm will receive lower-dose decitabine (7 mg/m2) administered intravenously within 1 hour for a consecutive 5 days, followed by TC regimen on day 6.

The primary endpoint of this trial was progression-free survival (PFS), defined as the time from the date of randomisation to the date of the first occurrence of any of the following events: appearance of any new lesions that could be measured or assessed clinically; or CA125 criteria of disease progression. For patients with measurable disease, clinical or radiographical tumour measurements had priority over CA125 levels, and progression during treatment could not be declared on the basis of CA125 alone.

Overall survival (OS), defined as the time from random assignment to death as a result of any cause, response rate, and adverse events.response to treatment, toxicity, and quality of life. Toxicities were evaluated per course and per patient (worst score over all courses).

Tumor measurements were made before each cycle by physical examination, before every third cycle by imaging methods in patients with measurable or evaluable disease, and after the last cycle. The same tumor assessment methods that were employed for baseline measurement were used for each repeat evaluation. Tumor response was graded according to Response Evaluation Criteria in Solid Tumors (RECIST).

Adverse events and toxicities were graded according to the National Cancer Institute Common Toxicity Criteria (NIC-CTC). Toxicities were recorded continuously; blood chemistry parameters were measured before each treatment cycle and weekly thereafter.Quality of life was assessed with the use of the European Organization for Research and Treatment of Cancer (EORTC) QLQ-C30 and QLQ-OV28 questionnaires.

Blood samples were obtained prior to treatment and at 0.25, 0.5, 1, 2, 4, 6, 8, and 24 hours after the first and fifth dose of decitabine. Plasma samples were stored and processed and further analyzed utilizing liquid chromatography/tandem mass spectrometry.

Peak plasma concentration (Cmax) or area under the plasma concentration versus time curve (AUC) will be obtained from more than 10 patients treated at a decitabine dose level of 7mg/m2/d.

To assess the pharmacodynamics of decitabine and to establish its relationship to clinical PFS, before and after decitabine treatment, peripheral blood mononuclear cells and/or tumor samples will be harvested for measurement of the expression and methylation profile including genes such as MLH1, RASSF1A, HOXA10, and HOXA11 by quantitative polymerase chain reaction (qPCR) and methylation-sensitive PCR analyses.