CHICAGO, June 5 -- For treatment-naive advanced thymoma or thymic carcinoma, carboplatin (Paraplatin) and paclitaxel (Taxol) failed to achieve response rates approaching those reported in published trials of athracycline-based regimens.
The Eastern Cooperative Oncology Group trial was the largest prospective trial of patients with these tumors of the anterior mediastinum. They account for only about 500 cases a year in the U.S., and only about a third are thymic carcinoma.
Action Points
- Explain to interested patients that this study describes an investigational treatment for a rare lung cancer and found that it did not demonstrate comparable efficacy when compared with standard therapy.
- This study was published as an abstract and presented at a conference. These data and conclusions should be considered to be preliminary until published in a peer-reviewed journal.
For this reason, suggested Girum L. Lemma, M.D., of Indiana University, it took the ECOG eight years to recruit 44 patients, he reported at the American Society of Clinical Oncology here.
There are a number of clinically unique features of the two cancers. Thymoma usually presents as early-stage disease, whereas thymic carcinoma is more likely to be at least locally advanced at diagnosis.
Paraneoplastic syndromes are common with thymoma, but rarely with thymic carcinoma, he said.
Finally, there have been several studies of anthracyline-based chemotherapy in thymoma and very little in the literature on chemotherapy regimens in thymic carcinoma.
In this trial, after stratification into 23 patients with thymoma and 21 with thymic carcinoma, patients were treated with carboplatin (AUC=6) plus paclitaxel at 225 mg/m2 every three weeks for a maximum of six cycles.
The response rate was 35% for thymoma patients and 29% for patients with thymic carcinoma. "Anthracyline-based regimens have achieved response rates of 50% to 90% in treatment-naive patients," he said.
The median progression-free survival was 19.8 months for thymoma patients and 5.0 months for patients with thymic carcinoma. Overall survival was more than 60 months for thymoma patients versus 15.1 months for thymic carcinoma patients.
Fifty-seven percent of the thymoma patients and 43% of the thymic carcinoma patients had stable disease after six cycles of chemotherapy.
There were no grade 5 toxicities and grade 3 and 4 toxicities were as expected -- neutropenia and fatigue.
Although a null trial, Dr. Lemma said the study confirmed that thymoma and thymic carcinoma differ in both clinical presentation and in prognosis.
| The National Cancer Institute funded the trial and Dr. Lemma made no financial disclosures. |
Primary Source
American Society of Clinical Oncology meeting
Source Reference: Lemma GL, et al "A phase II study of carboplatin plus paclitaxel in advanced thymoma or thymic carcinoma: E1C99" ASCO Meeting 2008; Abstract 8018.