Author of

• 10897

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  P1.15 - Poster Session 1 - Thymoma (ID 189)

  • Event: WCLC 2013
  • Type: Poster Session
  • Track: Thymoma & Other Thoracic Malignancies
  • Presentations: 1
  • Moderators:
  • Coordinates: 10/28/2013, 09:30 - 16:30, Exhibit Hall, Ground Level

  • 10901

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    P1.15-004 - Relationship of therapeutic results with immunohistochemical findings in thymic carcinoma cases (ID 1016)

    09:30 - 09:30  |  Author(s): T. Kimura
    • Abstract

    Background
    A thymic carcinoma is a thymic epithelial neoplasm that has a large number of malignant features as compared to a thymoma. Since a thymic carcinoma is presented with locally advanced disease or distant metastasis, unresectable cases are frequently encountered at diagnosis, thus systemic chemotherapy is a key treatment strategy. Although cisplatin-based chemotherapy is usually administered for such cases, an optimal regimen has not been established. To determine a prognostic indicator for chemotherapy in patients with thymic cancer we evaluated the expressions of excision repair cross complementing-1 (ERCC1), class III β-Tubulin (TubIII), ribonucleotide reductase M1 (RRM1), and thymidylate synthase (TS)/orotate phosphoribosyltransferase (OPRT), which have been reported as possible indicators of the anticancer activity of cisplatin, taxanes, gemcitabine, and 5-fluorouracil drugs such as S-1, respectively.

    Methods
    Thymic carcinoma tissue samples obtained from 15 patients who underwent surgery or core-needle biopsy procedures between 1996 and 2007 at Osaka University Hospital were used. Immunohistochemical analysis was utilized to determine the expressions of ERCC1, TubIII, RRM1, TS, and OPRT in thymic cancer specimens, then the relationship between expression levels and clinical course were examined in a retrospective manner.

    Results
    Twelve males and 3 females (median age, 60.3 years) were studied. The histological subtype was squamous cell carcinoma in 10, small cell carcinoma in 2, large-cell neuroendocrine carcinoma in 2, and carcinoid in 1, while Masaoka classification was stage III in 4, IVa in 4, and IVb in 7. Surgical resection was performed as initial treatment in 8 patients. Chemotherapy, mainly platinum-based combinations, was administered in 12, including 6 who received combined radiotherapy. The median number of administered regimens and cycles were 2 (range, 1-9) and 7 (range, 2-44), respectively, for each patient. The response rate/disease-control rates following first- and second-line treatments were 83%/92% and 56%/78%, respectively. In 6 patients treated with gemcitabine, 3 tumors with a low expression of RRM1 showed a good response, whereas 2 of 3 tumors with a high expression of RRM1 showed a progressive disease response. S-1 was administered to 1 patient, which successfully suppressed tumor progression, and the specimen from that case demonstrated a low expression of TS and high expression of OPRT. We were able to obtain biopsy specimens before and resected tumors after treatment from 5 patients, in which the expressions of ERCC1, Tub III, and RRM1 were increased after treatment in 4, 3, and 4, respectively. Our results suggest that sensitivity to chemotherapy is lowered with additional courses in thymic carcinoma patients. The median survival was 36 months, while the 1-, 3-, and 5-year survival rates were 81.9%, 55.5%, and 23.1%, respectively.

    Conclusion
    First-line chemotherapy with platinum compounds may be effective treatment for patients with thymic cancer, while new drugs such as gemcitabine and S-1 might be useful in some cases. Prospective multi-institutional studies are required to ascertain the effectiveness of immunohistochemical evaluation used as a screening test for selecting the optimum chemotherapy regimen for thymic cancer patients.