Chemotherapy for advanced thymoma. Preliminary results of an intergroup study

Cisplatin and Irinotecan as First-Line Chemotherapy for Previously Untreated Metastatic Thymic Carcinoma: Updated Analysis

Platinum-based chemotherapy is the de facto standard treatment for metastatic or unresectable thymic carcinoma. The optimal chemotherapy regimen has not yet been determined, including whether this should be combined with a second- or third-generation anti-cancer agent. We retrospectively evaluated the data of patients with metastatic or unresectable thymic carcinoma who were treated with a combination of cisplatin and irinotecan as first-line chemotherapy between 2002 and 2021 (trial registration UMIN000012175). The primary endpoint was response rate according to the RECIST criteria version 1.1. Secondary endpoints were disease control rate, progression-free survival (PFS), overall survival (OS), and toxicity (adverse events). Some patients analyzed in this study were also included in the previous trial, which was terminated early. For this analysis, we included 18 patients with a median age of 56 years and an Eastern Cooperative Oncology Group performance status of 0 or 1. All patients had clinical stage IVa or IVb thymic carcinoma according to the Masaoka-Koga staging system. The response rate was 44% and the disease control rate was 89%. The median PFS was 8.4 months (95% confidence interval (CI): 2.7–11.6 months) and the median OS was 45.6 months (95% CI: 15.7–69.1 months). Grade 3 or worse hematological toxicity was observed in 5 patients and grade 3 or worse non-hematological toxicity was observed in 3 patients. None of the patients developed febrile neutropenia, and no treatment-related deaths occurred. Thus, the combination of cisplatin and irinotecan as first-line chemotherapy for metastatic thymic carcinoma showed efficacy and acceptable toxicity.

Preoperative computed tomography findings predict surgical resectability of thymoma

INTRODUCTION

The aim of the study was to identify preoperative computed tomography (CT) imaging characteristics that correlated with surgical resectability.

METHODS

We retrospectively reviewed the CT scans of 133 patients who underwent surgical resection for thymoma at our institution between July 21, 1997, and September 22, 2010. Imaging characteristics recorded included tumor size, attenuation, contact of mediastinal vessels, tumor morphology, infiltration of surrounding fat, changes in the adjacent lung parenchyma, lymphadenopathy, and pleural involvement.

RESULTS

The study group included 66 men and 67 women, aged 23-88 years (mean 58.8 years). Eighty patients (60.2%) were Masaoka stage I or II and 53 (39.8%) were Masaoka stage III or IV. Twenty-three patients (17.3%) had an incomplete surgical resection. Of these, 15 patients had microscopic residual disease (11.2%) and eight had gross residual disease (6.0%). The preoperative CT characteristics that correlated with an incomplete surgical resection included a lobulated tumor contour (p = 0.016), greater than or equal 50% abutment of the circumference of an adjacent vessel (p < 0.001), thoracic lymphadenopathy (p = 0.029), adjacent lung changes (p = 0.005) and pleural nodularity (p = 0.001). Tumor size was larger in the incompletely versus completely resected groups, with mean values of 9.7 and 6.9 cm (p value 0.013). On multivariate analysis, only degree of abutment of adjacent vessels and pleural nodularity were independent predictors of incomplete resection.

CONCLUSIONS

Preoperative CT findings can predict the likelihood of successful surgical resection and could help to identify patients who might benefit from neoadjuvant chemotherapy.

Invasive spindle cell thymomas (WHO Type A): a clinicopathologic correlation of 41 cases

We report 41 cases of invasive spindle cell thymomas (World Health Organization type A). The patients were 16 women and 25 men between the ages of 38 and 80 years. Clinically, the patients had diverse symptomatology, including chest pain, cough, and dyspnea. None of the patients had a history of myasthenia gravis. According to the Mazaoka surgical staging system, 34 patients had stage II disease, 6 had stage III, and 1 had stage IV. Follow-up information showed that 30 patients were alive after a period ranging from 12 to 96 months; for 8 patients who are alive, the follow-up was less than 12 months; 1 patient died 10 months after initial diagnosis. For 2 patients, no follow-up information was obtained. This study stresses the fact that histologic features do not correlate with invasion or encapsulation because all thymomas, regardless of their histologic type, are capable of invasion.

Topoisomerase 2α plays a pivotal role in the tumor biology of stage IV thymic neoplasia

BACKGROUND

Microsatellite studies in histologic types B3 and C thymic neoplasia detected gains on chromosome 17q, which contains the Her-2/neu and its juxtaposed topoisomerase 2alpha (T2alpha) genes. The study aimed to evaluate their impact on tumor biology and survival of advanced thymic neoplasia patients.

METHODS

From 1991 to 2005, 36 consecutive stage IV thymic carcinoma patients were treated, 18 men and 18 women, aged 11 to 84 years. There were 22 thymic carcinoma, 13 type B3, and 1 type B2 thymoma. Patients received treatment consisting of surgical resection, combination chemotherapy with the CAP (cyclophosphamide, Adriamycin, cisplatin) regimen, or radiation therapy potentiated by high-dose weekly 5-fluorouracil infusion. Permutations of these 3 treatment modalities were prescribed as necessary.

RESULTS

T2alpha gene amplification was detected in 4 of 14 thymic carcinoma and 1 of 15 type B3 thymoma. Three thymic carcinoma patients had Her-2/neu coamplification and these 3 patients had rapidly growing tumor and extensive disease at initial diagnosis. CAP was prescribed in 28 patients and 20 patients responded (response rate, 71.4%, 95% confidence interval [CI]: 52.8% to 85%); all responders overexpressed (> or = 10% nuclei positive) the T2alpha protein, whereas 4 nonresponders had very low expression. T2alpha overexpression predicts CAP response, and its absence predicts resistance (P = .001). Overall survival was significantly prolonged if the tumor was resectable (P = .001), of type B3 histology (P = .0039), and had no Her-2 gene amplification (P = .0081).

CONCLUSION

T2alpha and Her-2/neu genes play a pivotal role in the tumor biology, CAP response, and survival of advanced thymic neoplasia patients.

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.

Atypical thymoma: A report of seven patients

BACKGROUND

Most thymic neoplasms fall under the designation of thymoma, consisting of well-differentiated epithelial cells, resembling normal thymus. At the opposite spectrum are thymic carcinomas; the cell of origin while similar is malignant. Recently a third category of thymic neoplasms, atypical thymomas, has been recognized representing thymic neoplasms manifesting atypia although without overt cytomorphologic criteria of malignancy.

METHODS

Seven patients with a diagnosis of atypical thymoma were encountered over a 6-year period from the patient files of the cardiothoracic division of The Ohio State Medical Center.

RESULTS

In all patients there was gross or light microscopic invasive disease with involvement of the capsule, phrenic nerve, diaphragm, chest wall, and lung. Surgical extirpation/de-bulking along with radiation therapy in six and chemotherapy in one led to complete disease regression. Intrathoracic recurrences developed in 4 involving lung, pleura, chest wall and diaphragm. All patients are well.

CONCLUSIONS

Atypical thymomas are locally aggressive tumors with a high incidence of intrathoracic recurrence; extrathoracic spread is not seen. Our study corroborates other reports that death attributable to atypical thymoma is uncommon.

Phase II study of a multidisciplinary approach with induction chemotherapy, followed by surgical resection, radiation therapy, and consolidation chemotherapy for unresectable malignant thymomas: final report

PURPOSE

To evaluate tumor resectability after induction chemotherapy and to determine disease-free and overall survival rates of patients with locally advanced unresectable thymoma that received a multimodal treatment regimen.

PATIENTS AND METHODS

Twenty-two patients (9 men, 13 women) with histologically confirmed invasive thymoma were treated with a multidisciplinary regimen consisting of three courses of induction chemotherapy, surgical resection, and radiation therapy, followed by three courses of consolidation chemotherapy. The median age was 47 years (range, 25-70). Eleven patients had stage III disease, 10 patients, stage IVA, and one patient, IVB. The most common histologic type was lymphocytic. Induction chemotherapy consisted of 500 mg/m(2) of cyclophosphamide on day 1; doxorubicin (20 mg/m(2) per day) on days 1-3 via continuous infusion (a total of 60 mg/m(2)); cisplatin (30 mg/m(2) per day) on days 1-3 (a total of 90 mg/m(2)); and prednisone (100 mg per day) on days 1-5. This cycle was repeated three times at 3-4-week intervals. Patients then underwent surgery for tumor resection and received radiotherapy. Consolidation chemotherapy given at 80% of the induction chemotherapy doses of cyclophosphamide, doxorubicin, and cisplatin and 100% of the dose of prednisone was then repeated every 3-4 weeks for a total of three courses.

RESULTS

Induction chemotherapy produced major responses in 17 (77%) of the 22 patients including 3 (14%) complete responses (CR) and 14 (63%) partial responses (PR). Twenty-one patients underwent surgical exploration: 16 (76%) had complete resection and 5 (24%) had incomplete resection; one patient refused surgery. All 22 patients received radiation therapy. Nineteen of 22 patients completed the planned therapy, and all but one had completed consolidation chemotherapy at the time of analysis. With a median follow-up time of 50.3 months, 18 of the 19 patients who completed the multidisciplinary approach were disease-free. Of the 22 patients originally registered, 20 were alive at the time of analysis (one patient died of endocarditis, and one died of recurrent disease). The overall survival rate was 95% at 5 years (95% confidence interval (CI), 0.87-1.0) and 79% at 7 years (95% CI, 0.55-1.0). The progression-free survival rates were 77% at 5 years (95% CI, 0.58-1.0) and 77% at 7 years (95% CI, 0.58-1.0). The major side effect from induction and consolidation chemotherapy was myelosuppression. Nine patients experienced grade III/IV neutropenia, which included neutropenic fever in two patients, and grade III thrombocytopenia in two patients. The most common nonhematologic side effects were fatigue, nausea and vomiting, and decreased appetite. One patient experienced acute respiratory distress syndrome after surgical resection and required a prolonged hospitalization. No patients developed cardiac toxic effects, and no surgical mortality occurred.

CONCLUSIONS

The use of induction chemotherapy to optimize surgical resectability of thymoma followed by radiation therapy and consolidation chemotherapy lead to good control of residual disease and high overall survival rates. We believe that this combined multidisciplinary approach prolongs lives and may cure locally advanced unresectable malignant thymomas. Future prospective multi-institutional studies are needed to further verify or define the best treatment for this patient population.

Multimodal management of stages III–IVa malignant thymoma

PURPOSE

The optimal therapy for locally advanced malignant thymoma is controversial. We review our experience with a multimodal approach in 63 consecutive cases.

PATIENTS AND METHODS

Forty-three patients had stage III and 20 stage IVa disease. Surgery with radical intent was initially performed in 30 cases, while 33 cases not amenable to radical surgery underwent neoadjuvant treatment (radiotherapy in 8 and chemotherapy in 25) before surgical reassessment. All patients, whether or not surgically resected, received radiation therapy.

RESULTS

Radical resection (RR) was performed in 20 patients ab initio (all stage III) and in 12 patients after neoadjuvant treatment (eight stage III and four stage IVa). With the addition of patients radically operated with neoadjuvant treatment, the radical resection rate increased from 46 to 65% in stage III patients, and from 0 to 20% in those with stage IVa disease, respectively. Radical surgery was associated with longer progression free survival and overall survival according to both univariate analysis ( P< 0.001 and P<0.01, respectively) and multivariate analysis after adjustment for age, gender, histology and disease stage ( P<0.001 and <0.02, respectively). Progression free survival (median 56.9 months) was slightly lower in patients undergoing radical surgery after neoadjuvant approaches than in those radically resected ab initio (median not achieved), but overall survival (median not achieved) was similar in both groups. Subtotal surgical resection promoted complete response to subsequent radiation therapy. This condition significantly correlated with a better outcome.

CONCLUSIONS

Complete surgical resection is an independent prognostic parameter in locally advanced thymoma treated with a multimodal approach. Preoperative treatment to increase the complete resection rate could improve the overall survival of these patients.

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

We describe two patients with invasive thymomas who responded to high-dose chemotherapy followed by peripheral blood stem cell transplantation (PBSCT) combined with surgery and radiotherapy. The first patient was a 42-year-old man admitted to the hospital with chest pain, and the second patient was a 45-year-old man admitted with myasthenia gravis. Both patients had nonresectable thymomas (stage IVa) because of invasion of the aorta, pulmonary artery, or both, and dissemination to the pericardium. They initially received two cycles of chemotherapy consisting of adriamycin (40 mg/m(2), day 1), cisplatin (50 mg/m(2), day 1), vincristine (0.6 mg/m(2), day 3), and cyclophosphamide (700 mg/m(2), day 4) at 3-week intervals. Four weeks later, they were administered high-dose etoposide (300 mg/m(2), days 1 to 5) followed by granulocyte colony-stimulating factor (G-CSF) [50 micro g/m(2)/d] subcutaneously to mobilize stem cells into the blood. After two additional cycles of adriamycin, cisplatin, vincristine, and cyclophosphamide (ADOC), the patients received high-dose ifosfamide (1.5 g/m(2), days 1 to 4), carboplatin (400 mg/m(2), days 3 to 5), and etoposide (200 mg/m(2), days 1 to 5) followed by PBSCT. They were administered G-CSF (50 micro g/m(2)/d) after PBSCT, with subsequent rapid recovery of neutrophil and platelet level. The tumors shrank remarkably, and could be excised completely in both patients. Postoperatively, 50 Gy of irradiation was administered. Disease-free status has been maintained for 5 years in the first patient and 2 years in the second patient. Our findings suggest that high-dose ifosfamide, carboplatin, and etoposide followed by PBSCT in combination with an ADOC regimen, surgery, and radiotherapy is very effective and well tolerated in patients with advanced nonresectable thymoma.

Thymic malignancies

Thymomas and thymic carcinomas are unique tumors of the anterior mediastinum. The association of a variety of different paraneoplastic syndromes with such lesions has fascinated physicians and researchers for years. Most recently, it has been demonstrated by numerous authors that thymomas are chemosensitive tumors. Their indolent nature and relative rarity have made evaluation through prospective randomized clinical trials extremely difficult. Further information regarding the molecular nature of these neoplasms and immunologic aspects is needed in future investigation.

On the histologic heterogeneity of thymic epithelial neoplasms. Impact of sampling in subtyping and classification of thymomas

Six hundred thirty cases of thymomas were evaluated to determine morphologic heterogeneity. The thymomas were grouped in 4 categories using previous terminology. Stratification according to the number of sections available for examination revealed a marked difference in distribution by histopathologic type. A cutoff number of 5 sections appears to provide a difference in subgrouping these tumors. In addition, the proportion of invasive tumors increases with the number of sections examined. Final classification may be affected by the extent of sampling. Histopathologic classification of thymoma, although of academic interest, may have limited practical relevance for assessment of prognosis in limited biopsy tissue. Proper evaluation of histology and aggressive potential in thymoma should be based on ample sampling and assessment of capsular integrity, which is best accomplished on thoroughly sampled resection specimens rather than incomplete or limited biopsy samples.

A novel second line chemotherapy treatment of recurrent thymoma

Thymoma is an uncommon malignancy which is initially treated with surgery. Combined modality treatment with radiation and chemotherapy is utilized in cases of unresectable or metastatic disease. In patients with relapse, a number of different chemotherapeutic regimens have been used with varying success. The case of a male with recurrent thymoma treated with carboplatin and paclitaxel is presented and the literature reviewed. The patient responded to this novel regimen with improvement in clinical symptoms and reduction in tumor mass. This novel regimen has shown activity as second line therapy and merits further investigation as a first line treatment for patients with invasive and or metastatic thymoma.

Plain radiography and computed tomography of invasive thymomas: clinico-radiologic-pathologic correlation

Fifteen computed tomography (CT) scans in nine patients with invasive thymoma are presented. The CT findings were an anterior mediastinal mass (89%), pleural deposits (78%), local infiltration of the mediastinum (100]), invasion of the cardiovascular structures (22%), lung invasion (11%) and diaphragmatic or subdiaphragmatic deposits (33%). Radiologic-pathologic correlation available in six patients showed a sensitivity of 89.5%, specificity of 87.5% and accuracy of 88.6% for CT. We conclude that CT is superior to plain radiography in the diagnosis of invasive thymoma. It provides an accurate pre-operative assessment by better demonstration of the full extent of abnormalities, and is useful in surgical planning, monitoring of therapeutic response and detecting recurrence.

Tumor lysis syndrome in invasive thymoma with peripheral blood T-cell lymphocytosis

Tumor lysis syndrome has rarely been observed in solid tumors. We report a case of a patient with advanced invasive thymoma associated with peripheral blood T-cell lymphocytosis in whom tumor lysis syndrome developed after chemotherapy. The potential for tumor lysis syndrome should be anticipated when treating extensive thymoma.

Prognostic importance of histomorphologic subclassification for epithelial thymic tumors

BACKGROUND

The prognostic importance of various clinical variables (age, sex, association with myasthenia gravis), staging according to Masaoka, histologic type according to the Marino/Kirchner/Müller-Hermelink (MKM-H) classification, and residual tumor category (R category) was evaluated in a retrospective analysis.

METHODS

Eighty-two patients with epithelial thymic tumors (ETTs) treated in the period 1969-1993 were evaluated, and archived specimens were histologically reclassified according to the classification of MKM-H.

RESULTS

Age, sex, and association with myasthenia gravis were of no prognostic importance. The R category is of significant prognostic importance, with 5- and 10-year survival rates of 93.6% and 87.3%, respectively, for R0 resections compared with 0% at 5 years for R1 and R2 resections (p < 0.001). Staging (Masaoka) proved to be a prognostic factor (5-/10-year survival: stage I, 100%/90.9%; II, 95%/88.2%; III, 55.9%/46.6%; and IV, 10.8%/ 10.8%; p < 0.001). Histologic typing according to MKM-H is also of significant prognostic importance (5/10 year survival: thymomas: medullary, 100%/100%; mixed, 100%/100%, predominantly cortical, 68.6%/68.6%; cortical, 65.8%/65.8%; thymic carcinomas: well-differentiated type, 62.3%/44.5%; thymic carcinomas other than well-differentiated type, 33.6%/26.9%; p < 0.001). Multivariate analysis demonstrated that staging (p < 0.001), R category (p < 0.026), and MKM-H classification (p < 0.028) have an independent impact on survival.

CONCLUSIONS

Staging (Masaoka), R category, and histologic classification (MKM-H) are important independent prognostic factors for patients with epithelial thymic tumors. Complete (R0) surgical resections should be the ultimate goal in the clinical management of patients with epithelial thymic tumors.

Treatment of pediatric malignant thymoma: long-term remission in a 14-year-old boy with EBV-associated thymic carcinoma by aggressive, combined modality treatment

Malignant thymoma, including thymic carcinoma, is extremely uncommon in the pediatric population. It is known to have a very poor outcome. We report on a 14-year-old boy with Epstein-Barr virus (EBV)-associated thymic carcinoma. Sections of the original tumor were analyzed for EBV by in situ hybridization to confirm the histological diagnosis of a lymphoepithelioma-like subtype. High copy numbers of EBV RNA were detected in the tumor tissue, suggesting an etiological role of EBV in our case. Intensive treatment resulted in long-term remission over 12 years. In order to facilitate the difficult management of the rare child with malignant thymoma, a literature search was initiated. Forty well-documented pediatric cases of malignant thymoma were found in the literature. Histological characteristics, clinical features, and therapeutic regimens were reviewed. Having the very limited experience with malignant thymoma in childhood in mind, it is concluded that its aggressiveness makes the most intensive treatment necessary. Long-term remission can be achieved by application of radical surgery, high-dose irradiation, and multiagent chemotherapy. The combination of cisplatinum, etoposide, and ifosfamide seems to be promising.

Prognostic factors of patients with thymoma

OBJECTIVES

To analyze the prognostic factors influencing the survival of patients with thymoma, clinical characteristics, treatment modalities and survival of patients were evaluated. The efficacy of chemotherapy was also determined.

METHODS

Retrospective study was done on one hundred patients whose diagnosis was confirmed pathologically at Seoul National University Hospital from 1981 to 1994. The staging was carried out according to the Masaoka system. Survival rate was calculated by the Kaplan-Meier method and prognostic factors were analyzed by a multivariate analysis (Weibull model).

RESULTS

The stage of 100 patients was as follows: Stage I-50, II-6, III-27, IV A-10, IV B-7. The overall survival rates at 5 and 10 years after diagnosis were 73.1% and 58.7%, respectively. The 5-year survival differences, according to various prognostic factors, were as follows: 1) Stage: I-92.8%, II-100%, III-71.6%, IVA-25.9% and IVB-32.9% (p = 0.0029). 2) Age: < 60 years-79.5% and > or = 60 years-41.5% (p = 0.0489). 3) Extent of resection: Total patients: complete resection-87.6% and incomplete resection-50.5% (p > 0.05) Stage III: complete resection-66.7% and incomplete resection-75.5% (p > 0.05) 4) Myasthenia gravis: present-71.6% and absent-74.9% (p > 0.05) Seventeen patients were treated with a combination chemotherapy of Cyclophosphamide, Adriamycin and cisplatin(CAP). Two complete responses and seven partial responses (overall response rate of 53%) were observed with a median response duration of fourteen months. Combination chemotherapy with CAP was effective.

CONCLUSIONS

Stage and age were the independent prognostic factors in patients with thymoma. However, the presence of myasthenia gravis or the extent of resection in stage III patients was not associated with the survival time.

Combination chemotherapy with a five-drug regimen for invasive thymoma

Nine patients with stage III and stage IV thymoma were treated with cisplatin, vincristine, lomustine, cyclophosphamide and prednisolone. Two patients (22%) obtained remission, and four patients (44%) showed no change for 11 to 31 months. It was found that this five-drug regimen did not improve the results obtained by other chemotherapy modalities for thymoma.

P-glycoprotein positive, drug resistant invasive lymphoepithelial thymoma: treatment response to chemotherapy with cyclosporin and quinine

A case of invasive drug resistant thymoma, expressing P-glycoprotein, which showed noticeable clinical response to chemotherapy and the multidrug resistance modulating agents cyclosporin and quinine is reported. A 46 year old man presented with severe left shoulder pain and a diagnosis of invasive lymphoepithelial thymoma was made following chest x ray and a computed tomography scan. The patient underwent extensive chemotherapy without resolution of the tumour. More than 90% of the malignant epithelial cells were strongly positive for P-glycoprotein and based on this observation, cyclosporin and quinine were added to the chemotherapy regimen. The mediastinal mass completely resolved and the size of the pleural metastasis decreased substantially. The patient, however, died of an intercurrent infection. This case report highlights the feasibility and efficacy of using cyclosporin and quinine in combination with VAD chemotherapy in the treatment of invasive thymoma.

Thymoma. A retrospective study of 87 cases

BACKGROUND

The authors retrospectively analyzed 87 patients with malignant thymoma treated at M.D. Anderson Cancer Center between 1951 and 1990. The analysis examined the clinical stages, histologic types, and treatment modalities and attempted to determine if chemotherapy had an impact on survival.

METHODS

The patients were divided into three groups by their year of treatment and treatment modality. Patients treated between 1951 and 1975 were in Group I; patients treated between 1976 and 1980 were in Group II; and patients treated between 1981 and 1990 were in Group III. Most of the patients (18 [72%] in Group I; 16 [62%] in Group II; and 18 [50%] in Group III) had surgical resection alone or with radiotherapy. Patients with advanced-stage disease in Group I received single-agent chemotherapy, whereas patients with advanced-stage disease in Group II received a different, combination chemotherapy regimen, and those in Group III were treated primarily with cisplatin- and doxorubicin-based combination chemotherapy, e.g., the cyclophosphamide doxorubicin, and cisplatin with or without prednisone. The 17 patients treated with cisplatin with or without prednisone were separately evaluated for survival according to their response.

RESULTS

Twenty-eight patients (5 [20%] in Group I; 6 [23%] in Group II; and 17 [47%] in Group III) received chemotherapy alone or after surgery or radiotherapy. The cisplatin with or without prednisone regimen was used in 17 Group III patients for initial treatment or for relapse. The overall response rate among the patients receiving the cisplatin with or without prednisone regimen was 64%; 6 (35%) had a complete response, and 5 (29%) had a partial response. Thirty-one (36%) of the 87 total patients had 45 recurrent tumors; the lung (29%), pleura (22%), and mediastinum (18%) were the most common sites of recurrence, whereas bone was the most common distant metastatic site. The 5-year survival rate was 70% in patients with Stage I disease, 71% in patients with Stage II or III disease, and 46% in patients with Stage IV disease. The 10-year survival rate was 70% in patients with Stage I disease, 47% in patients with Stage II or III disease, and 21% in patients with Stage IV disease. Statistical analysis indicated a significant difference among the survival rates of patients with noninvasive Stage I, invasive Stage II plus III (P = 0.033), and Stage II plus III and IV tumors (P = 0.056), but not between patients with Stage II or III tumors. Patients with a major response to the cisplatin with or without prednisone regimen had a significant survival improvement compared to those with no response (P = 0.002, log-rank test).

CONCLUSIONS

Because thymoma is a chemosensitive tumor and frequently recurs in patients with Stage II or greater disease, chemotherapy carries a potential survival benefit and should be incorporated into the multimodality approach to prolong disease-free survival.

Thymoma

Thymomas and thymic carcinomas are thymic epithelial tumors that constitute approximately 15% of all mediastinal masses. From 28 to 66% of thymomas cause chest symptoms as the initial manifestation; the rest are discovered on routine chest roentgenograms or during investigations prompted by the presence of a paraneoplastic syndrome. Forty percent of patients with thymoma have one or more paraneoplastic syndromes, including myasthenia gravis, pure red cell aplasia, and hypogammaglobulinemia. Extrathymic malignant lesions develop in up to 20% of patients. Traditional histologic classifications have not accurately predicted tumor behavior; a recently developed classification based on cellular differentiation toward thymic medullary or cortical epithelium may correlate better with prognosis. Nevertheless, the prognosis is best predicted by stage of the tumor determined intraoperatively and is poorer in patients with incomplete resection than in those with complete resection of the thymoma. In addition to surgical intervention, irradiation and chemotherapy have important roles in the management of thymomas, particularly in advanced stages. In this article, the clinical manifestations, diagnosis, pathologic features, staging, and treatment of thymomas are reviewed, and the prognosis of affected patients is discussed.

Current therapy for thymoma

Thymomas are the most frequently encountered neoplasm of the anterior mediastinum. Thymic neoplasms can be divided into 3 broad categories based on histologic appearance and behavior. Thymomas are tumors with benign-appearing cellular features. If there is no gross or microscopic invasion beyond the capsule, the tumor is considered benign. Any tumor with gross or microscopic invasion through the capsule is considered malignant. In a third category, thymic tumors which have histologically malignant epithelial features, are considered thymic carcinomas and generally have an adverse prognosis. Microscopically, thymomas consist of a variable component of lymphocytic, epithelial, and fusiform (spindle) cell elements. The tumors may be classified according to the predominant cell type or are considered mixed if no cell type predominates. Prognosis is most strongly linked to clinical stage. The role of adjuvant radiotherapy or chemotherapy in the treatment of such tumors is controversial, but malignant thymomas are generally responsive to radiotherapy. Associated myasthenia gravis does not adversely affect the prognosis of thymoma, and medical attention to the myasthenia may contribute to earlier diagnosis of the thymoma. Cisplatin-based chemotherapy may be used to treat advanced disease with a modest response rate.

Nocardiosis after corticosteroid therapy for malignant thymoma

BACKGROUND

Nocardia asteroides is an opportunistic infection caused by an aerobic actinomycete, which, in the immunocompromised host, can be associated with severe invasive disease with a predilection for the brain.

METHODS AND RESULTS

The authors describe a 62-year-old man with a malignant thymoma that was clinically responsive to oral prednisone. N. asteroides sepsis subsequently developed, leading to his death.

CONCLUSIONS

Nocardiosis should be considered a potential pathogen in this immunocompromised setting.

Thymic carcinoma. A distinct clinical entity responsive to chemotherapy

BACKGROUND

Thymic carcinomas are rare tumors of the anterior mediastinum. These tumors are distinct thymic neoplasms that differ from their more common counterpart, thymoma. As opposed to thymomas, thymic carcinomas are histologically malignant neoplasms with a clinical course that tends to be much more aggressive than that of patients with thymoma.

METHODS

Between 1984 and 1990, five patients with thymic carcinoma treated with cisplatin-based combination chemotherapy were seen at Indiana University Hospital. These patients' diagnoses, courses, and treatments were reviewed.

RESULTS

Three patients responded (two completely) to cisplatin-based chemotherapy.

CONCLUSIONS

This form of chemotherapy merits additional study in such patients, and our experience indicates that at least some will have clinically meaningful responses. The optimum regimen is unclear, but would contain cisplatin and probably should be similar to that used in germ cell tumors.