A randomised study of carboplatin vs sequential ifosfamide/carboplatin for patients with FIGO stage III epithelial ovarian carcinoma. The London Gynaecologic Oncology Group

Efficient statistical inference for a parallel study with missing data by using an exact method

In a parallel group study comparing a new treatment with a standard of care, missing data often occur for various reasons. When the outcome is binary, the data from such studies can be summarized into a 2 × 3 contingency table, with the missing observations in the last column. When the missingness is neither related to the outcome of interest nor related to other outcomes from the study but it is covariate dependent with the sole covariate being treatment, this type of missing data mechanism is considered as missing at random. In 2016, Tian et al.  proposed three statistics to test the hypothesis that the response rate is equivalent for a parallel group study with missing data. The asymptotic limiting distributions of these test statistics were used for statistical inference. However, asymptotic approaches for testing proportions generally do not have satisfactory performance with regard to type I error rate control for a clinical trial with the sample size from small to medium. For this reason, we consider an exact approach based on maximization to provide valid and efficient statistical inference for a parallel group study with missing data. Exact approaches can guarantee the type I error rate and they are computationally feasible in this setting. We conduct extensive numerical studies to compare the performance of the exact approach based on the three statistics for a one-sided hypothesis testing problem. We conclude that the exact approach based on the likelihood ratio statistic is more powerful than the exact approach based on the other two statistics. Two real clinical trial data sets are used to illustrate the application of the proposed exact approach.

Survival effect of maximal cytoreductive surgery for advanced ovarian carcinoma during the platinum era: a meta-analysis

PURPOSE

To evaluate the relative effect of percent maximal cytoreductive surgery and other prognostic variables on survival among cohorts of patients with advanced-stage ovarian carcinoma treated with platinum-based chemotherapy.

MATERIALS AND METHODS

Eighty-one cohorts of patients with stage III or IV ovarian carcinoma (6,885 patients) were identified from articles in MEDLINE (1989 through 1998). Linear regression models, with weighted correlation calculations, were used to assess the effects on log median survival time of the proportion of each cohort undergoing maximal cytoreduction, dose-intensity of the platinum compound administered, proportion of patients with stage IV disease, median age, and year of publication.

RESULTS

There was a statistically significant positive correlation between percent maximal cytoreduction and log median survival time, and this correlation remained significant after controlling for all other variables (P <.001). Each 10% increase in maximal cytoreduction was associated with a 5.5% increase in median survival time. When actuarial survival was estimated, cohorts with < or = 25% maximal cytoreduction had a mean weighted median survival time of 22.7 months, whereas cohorts with more than 75% maximal cytoreduction had a mean weighted median survival time of 33.9 months--an increase of 50%. The relationship between platinum dose-intensity and log median survival time was not statistically significant.

CONCLUSION

During the platinum era, maximal cytoreduction was one of the most powerful determinants of cohort survival among patients with stage III or IV ovarian carcinoma. Consistent referral of patients with apparent advanced ovarian cancer to expert centers for primary surgery may be the best means currently available for improving overall survival.

Phase II clinical trials of cisplatin-then-paclitaxel and paclitaxel-then-cisplatin in patients with previously untreated advanced epithelial ovarian cancer

PURPOSE

To examine the activity and safety of two sequentially scheduled chemotherapy regimens comprising four cycles of paclitaxel (pctx) 200 mg/m2/3 hours then four cycles ofcisplatin (cisDDP) 100 mg/m2, and vice versa, in patients with previously untreated advanced ovarian cancer.

PATIENTS AND METHODS

Between January 1994 and February 1996, we recruited 30 patients to the pctx-then-cisDDP regimen and 29 to cisDDP-then-pctx, in parallel phase II trials.

RESULTS

Both regimens were predictably active with responses seen in 22 of 30 patients (OR 74%; CR 27%, PR 47%) treated with pctx-then-cisDDP, as against 13 of 21 patients (OR 62%; CR 38%, PR 24%) treated with cisDDP-then-pctx. The OR rate to four cycles of pctx (induction) was 43%, with 27% disease progression; the OR to four cycles of cisDDP (induction) was 57%, with 5% progression. However, progression rates across both induction and consolidation phases were 16% (pctx-then-cisDDP) and 29% (cisDDP-then-pctx). Both regimens were unacceptably neurotoxic. II patients suffering grade 3 sensory neurotoxicity (5 on pctx-then-cisDDP, 6 on cisDDP-then-pctx) and 20 having grade 3 deafness (9 on pctx- then-cisDDP, 11 on cisDDP-then-pctx).

CONCLUSION

The activity of these sequential regimens justifies their further development using the less neurotoxic platinum analogue carboplatin, perhaps combining paclitaxel with other platinum non-cross resistant drugs.

Phase III randomized study of cisplatin versus paclitaxel versus cisplatin and paclitaxel in patients with suboptimal stage III or IV ovarian cancer: a gynecologic oncology group study

PURPOSE

To assess progression-free survival (PFS) and overall survival (OS) in patients with suboptimally debulked epithelial ovarian cancer receiving cisplatin (100 mg/m(2)) or 24-hour infusion paclitaxel (200 mg/m(2)) or the combination of paclitaxel (135 mg/m(2)) followed by cisplatin (75 mg/m(2)).

PATIENTS AND METHODS

After stratification for disease measurability, patients were randomized to receive six cycles of one of the treatments every 3 weeks. If measurable, complete response (CR) or partial response (PR) was determined.

RESULTS

Six hundred fourteen of 648 patients who entered onto the trial were eligible. Monotherapies were discontinued more frequently (cisplatin because of toxicity or patient refusal [17%], and paclitaxel because of progression [20%]) compared with the combination therapy (7% and 6%, respectively). Neutropenia, fever, and alopecia were more severe with paclitaxel-containing regimens; whereas anemia, thrombocytopenia, neurotoxicity, nephrotoxicity, and gastrointestinal toxicity were more severe with cisplatin-containing regimens. The CR/PR rates on paclitaxel monotherapy were significantly lower compared with the cisplatin regimens (42% v 67%, respectively; P <.001). The relative hazard (RH) of first progression or death was significantly greater among those randomized to paclitaxel (RH = 1.41; 95% confidence interval [CI], 1.15 to 1.73; P <.001) when compared with cisplatin; however, RH did not differ significantly between the two cisplatin regimens (RH = 1.06; 95% CI, 0.895 to 1.30). Relative to cisplatin, the death rate on paclitaxel was 15% greater (RH = 1.15; 95% CI, 0. 929 to 1.42), and the death rate on the combination treatment was 1% less (RH = 0.99; 95% CI, 0.795 to 1.23). These differences among treatment groups were not statistically significant (P =.31).

CONCLUSION

Cisplatin alone or in combination yielded superior response rates and PFS relative to paclitaxel. However, OS was similar in all three arms, and the combination therapy had a better toxicity profile. Therefore, the combination of cisplatin and paclitaxel remains the preferred initial treatment option.

Phase II trial of ifosfamide and cisplatinum in advanced ovarian cancer

To evaluate the efficacy of systemic ifosfamide, cisplatin (CDDP) combination as first line treatment followed by intraperitoneal (IP) chemotherapy with carboplatin (CBCDA) and etoposide as consolidation in patients with stage III and IV epithelial ovarian cancer. A total of 40 patients with stage III and IV ovarian cancer were entered into the study. Ifosfamide 1 g/m2 plus mesna 1 g/m2 was given as six hour infusion daily for six days and CDDP 75 mg/m2 was given on day seven. Patients completing six cycles of systemic therapy underwent second look laparotomy followed by four cycles of IP chemotherapy with CBCDA 300 mg/m2 and etoposide 200 mg/m2. Of the 40 patients entering the protocol 27 patients completed six cycles with a complete remission (CR) of 65% and overall response of 67.5%. Twenty-two patients underwent second look laparotomy with pathological CR in ten patients, microscopic disease in seven and macroscopic disease in five. Eleven patients completed four cycles of IP chemotherapy. At 52 months was the overall survival (OS) was 36%. The disease free survival (DFS) at 45 months was 38%. Factors affecting OS were ascites (p < 0.011), stage (p < 0.04), weight change (p < 0.017), residual disease (p < 0.001), number of chemotherapy cycles (p < 0.0001) and IP chemotherapy (p < 0.006). Presently 35% patients are alive in CR, 15% are alive with disease, one patients has been lost to follow up while 47.5% have died. Of these four patients had progressive disease, seven relapsed, four died due to treatment related complications and two died in CR due to other causes. Subset analysis of 22 patients who had second look laparotomy and completed four cycles of IP chemotherapy revealed a distinct survival advantage. IFOS + CDDP is an effective combination as first time treatment in advanced ovarian cancer. IP chemotherapy is effective as consolidation and seems to provide a significant survival advantage. Further studies with larger number of patients need to be done to confirm these results.

Single-agent paclitaxel in patients with previously untreated stage IV epithelial ovarian cancer. London Gynaecological Oncology and North Thames Gynaecological Oncology Groups

The aim of this study was to evaluate the efficacy of high-dose paclitaxel in patients with previously untreated stage IV epithelial ovarian cancer. Paclitaxel was administered intravenously over 3 h at a dose of 225 mg m(-2) on a 21-day cycle for six courses. Thirty-six patients were entered into this study; all 36 were assessed for toxicity and 33 patients were evaluable for response. One patient had a complete response and 12 patients had partial responses (overall response rate 39.4%, 95% CI 23-58%). The overall median duration of response was 9 months (range 3.5-23+ months). The response rate to carboplatin following failure of paclitaxel within 1 year of stopping therapy was 57% (four out of seven patients). The median survival of patients was 17.2 months. The main toxicity encountered was neutropenia which was WHO grade 3 in 11 patients (31%) and WHO grade 4 in seven patients (19%). Granulocyte colony-stimulating factor (GCSF) was not given to any patient during the study. Other toxicities were: grade 3/4 infection (11%) and nausea and vomiting (11%); grade 3 bone pain (22%), fatigue (14%), diarrhoea (3%), myalgia/arthralgia (3%) and dry eyes (3%). Transient peripheral neuropathy occurred in 16 patients (44%), and alopecia was encountered in most patients (grade 2/3, 78%). Paclitaxel given at 225 mg m(-2) to patients with stage IV epithelial ovarian cancer is active, well tolerated and does not require GCSF support.