Multidisciplinary therapy including high-dose chemotherapy followed by peripheral blood stem cell transplantation for invasive thymoma

Thymic epithelial tumors: analysis of prognostic factors with emphasis on the role of adjuvant radiation therapy

BACKGROUND

The prognostic impacts of histopathological classification, Masaoka staging system, extent of surgery, and adjuvant treatment approaches in thymic epithelial tumors (TETs) were investigated.

MATERIAL AND METHODS

Records of 22 patients were retrospectively reviewed. Total thymectomy was performed on 5 patients and thymectomy on 17. Complete resection was achieved for 14 patients. Radiation therapy (RT) was considered for all patients with stage III or IV disease and all patients undergoing incomplete resections.

RESULTS

Local control had been achieved in all patients and all were alive with no evidence of disease (ANED) at 0.2-7.8 years (median, 2.3 years). Of 4 patients with stage II disease, 2 (favorable group) had undergone complete resections and 2 (intermediate group) had undergone incomplete resections. Those undergoing incomplete resections had received RT. Of these 4 patients, all were ANED. All 4 patients with Masaoka stage III disease that were involved in the study had undergone incomplete resections and had received RT. Also, these patients were ANED.

CONCLUSIONS

Patients with TETs undergoing less than complete resections might be referred for RT in the postoperative setting, while the role of RT in patients undergoing complete resections remains unclear.

The role of chemotherapy in advanced thymoma

BACKGROUND

Thymoma and thymic carcinomas are rare malignancies. Most thymomas and about one-third of thymic carcinomas can be cured with local therapy. The remainder of will be candidates for systemic therapy. Numerous retrospective trials confirm objective responses to a variety of single-agent and combination chemotherapeutic regimens.

METHODS

No prospective randomized comparison of regimens has been performed because of the rarity of the disease. This paper reviewed the literature of chemotherapy in advanced thymic malignancies.

RESULTS

Existing data suggest that anthracycline plus cisplatin regimens seem to demonstrate higher response rates and perhaps longer median survival times compared with nonanthracycline-containing regimens.

DISCUSSION

Thymic malignancies are sensitive to a broad spectrum of systemic agents. Thymic carcinoma has a distinct clinical presentation and worse therapeutic outcomes than thymoma. Despite reproducible high response rates in thymoma, durable complete remissions are rare. Thus, novel new therapeutic targets need to be identified and appropriate agents developed to have further impact on this disease.

Thymoma: Benign Appearance, Malignant Potential

Thymoma is a rare tumor with a largely indolent growth pattern. It does, however, have malignant potential as a result of its ability to invade locally and metastasize regionally. Often associated with a number of immune- and nonimmune-mediated paraneoplastic syndromes, patient outcomes are directly related to stage of disease and the ability to achieve a complete surgical resection. Surgery is the mainstay of treatment, with adjuvant radiation recommended for invasive thymoma. Sensitive to both chemotherapy and radiation, durable responses are achievable in incompletely resected and inoperable patients. We present two cases of thymoma followed by a general discussion with an emphasis on treatment for both early and advanced-stage disease.

Advanced Stage Thymomas and Thymic Carcinomas: Results of Multimodality Treatments

BACKGROUND

With the aim of evaluating the results of multidisciplinary approaches, we reviewed our experience in multimodality treatment of advanced stage (III and IVA) thymic tumors.

METHODS

From 1976 to 2003, 56 patients with Masaoka stage III and IVA thymic tumors underwent a multimodality treatment. Thirty-six patients underwent neoadjuvant chemotherapy, surgery, and postoperative radiotherapy; 20 patients were treated by primary surgery and postoperative radiotherapy (n = 12), chemotherapy (n = 1) or chemoradiotherapy (n = 7). The neoadjuvant or adjuvant chemotherapy consisted of three courses of cisplatin, epidoxorubicin, and etoposide every 3 weeks. Adjuvant radiotherapy consisted of 45 Gy for complete resections or 60 Gy for incomplete resections.

RESULTS

The preoperative diagnosis of invasive thymomas was performed in a total of 29 cases: 15 by mediastinotomy, 6 by video-assisted thoracoscopic surgery, and 8 by fine-needle aspiration. In 27 cases no diagnosis was available, but in most of them a thymus-related syndrome was present. Thirty-four patients are still alive (31 disease-free), and 22 have died (2 disease-free). Ten-year survival was 48% and 45.7% for stage III and IVA thymomas, respectively. The presence of myasthenia gravis (p = 0.04) and neoadjuvant chemotherapy (p = 0.004) affected survival significantly.

CONCLUSIONS

The multimodality treatment of stage III and IVA thymic tumors allows a good long-term outcome; the neoadjuvant chemotherapy improves the resectability rate and the survival of both stages of the disease.

Treatment of malignant thymoma

PURPOSE OF REVIEW

The present review reports findings in the field of epithelial tumors originating from the thymus from the past year and discusses these findings in the context of the literature.

RECENT FINDINGS

Epithelial tumors of the thymus are relatively common tumors of the anterior superior mediastinum. Thymomas are usually slowly growing tumors, and their prognosis depends on the macroscopic and microscopic invasion of surrounding tissues. Thymic carcinomas are more aggressive and less common tumors than thymomas and have been increasing in frequency in recent years. Surgery is the mainstay treatment of thymic malignancies, and complete resection represents the best prognostic factor in this disease. Postoperative radiotherapy may be indicated in tumors with invasion of surrounding tissues, but it is controversial in early-stage thymomas. Combination chemotherapy has been employed in several small studies and in advanced disease has been demonstrated to produce a 50-80% objective response rate. Neoadjuvant chemotherapy or external beam radiotherapy have been used with success in patients with tumors that are not readily resectable. Novel antiproliferative systemic agents are being investigated, based on a better understanding of the biology of these tumors.

SUMMARY

A better understanding of the clinical behavior of thymomas versus thymic carcinomas and systemic therapies targeted to biologically validated targets in these diseases will help improve efficacy of treatment.