Platinum-based chemotherapy with or without thoracic radiation therapy in patients with unresectable thymic carcinoma

American Radium Society Appropriate Use Criteria for Radiation Therapy in the Multidisciplinary Management of Thymic Carcinoma

Importance

Thymic carcinoma is rare, and its oncologic management is controversial due to a paucity of prospective data. For this reason, multidisciplinary consensus guidelines are crucial to guide oncologic management.

Objective

To develop expert multidisciplinary consensus guidelines on the management of common presentations of thymic carcinoma.

Evidence Review

Case variants spanning the spectrum of stage I to IV thymic carcinoma were developed by the 15-member multidisciplinary American Radium Society (ARS) Thoracic Appropriate Use Criteria (AUC) expert panel to address management controversies. A comprehensive review of the English-language medical literature from 1980 to 2021 was performed to inform consensus guidelines. Variants and procedures were evaluated by the panel using modified Delphi methodology. Agreement/consensus was defined as less than or equal to 3 rating points from median. Consensus recommendations were then approved by the ARS Executive Committee and subject to public comment per established ARS procedures.

Findings

The ARS Thoracic AUC panel identified 89 relevant references and obtained consensus for all procedures evaluated for thymic carcinoma. Minimally invasive thymectomy was rated as usually inappropriate (regardless of stage) due to the infiltrative nature of thymic carcinomas. There was consensus that conventionally fractionated radiation (1.8-2 Gy daily) to a dose of 45 to 60 Gy adjuvantly and 60 to 66 Gy in the definitive setting is appropriate and that elective nodal irradiation is inappropriate. For radiation technique, the panel recommended use of intensity-modulated radiation therapy or proton therapy (rather than 3-dimensional conformal radiotherapy) to reduce radiation exposure to the heart and lungs.

Conclusions and Relevance

The ARS Thoracic AUC panel has developed multidisciplinary consensus guidelines for various presentations of thymic carcinoma, perhaps the most well referenced on the topic.

Radiographic Predictors of Resectability in Thymic Carcinoma

BACKGROUND

The aim of this study was to assess preoperative computed tomography characteristics of thymic carcinomas and to investigate which features could predict an incomplete surgical resection. A secondary aim was to correlate preoperative imaging features with Masaoka stage.

METHODS

In this study, approved by our Institutional Review Board, two readers retrospectively reviewed preoperative computed tomography scans at our tertiary referral oncology center between 1994 and 2014. Imaging features analyzed included tumor morphology, infiltration of surrounding mediastinal fat, loss of surrounding fat plane, degree of contact between tumor and great vessels, and associated pulmonary or pleural abnormality. Surgical and pathologic records were reviewed for completeness of surgical resection and Masaoka stage.

RESULTS

Forty-one patients were included, with Masaoka stage I (n = 3), stage II (n = 4), stage III (n = 12), and stage IV (n = 22). Twenty-one patients (51%) had a complete surgical resection. Ten had microscopic residual disease (R1) with involved surgical margins at pathology, and 10 patients had macroscopic residual disease (R2) at surgery. In addition to lesion size, the feature associated with incomplete surgical resection was the degree of tumor contact with adjacent mediastinal vessels on the preoperative computed tomography image (p = 0.038). Many of the more common features associated with incomplete resection were also more likely to be present in patients with late Masaoka stage (III/IV), including infiltration of the mediastinal fat, which was present in all 34 patients with Masaoka stage III/IV compared with 5 patients (71%) with stage I/II (p = 0.03).

CONCLUSIONS

Preoperative computed tomography imaging features may help to identify patients at risk for an incomplete surgical resection.

Ectopic right parietal pleural thymic carcinoma: a rare case and review of the literature

Ectopic thymic carcinoma is extremely rare. We present a case of a 73-year-old male patient with ectopic right parietal pleural thymic carcinoma and performed a literature review. Computed tomography (CT) of the chest demonstrated a sharp-edged soft tissue mass with intense enhancement measuring 47 mm × 29 mm with a broader base adjacent to the right axillary chest wall at the level of the 5th rib. There was no hilar or mediastinal lymphadenopathy or evidence of a mediastinal tumor or pleural nodules. A totally extra-pleural tumor resection and partial right lung resection was performed. Histological examination demonstrated infiltrative growth typical of carcinoma cells with a nest-like distribution locally invading the surface of the lung tissue. Immunohistochemical examination confirmed the diagnosis of thymic squamous carcinoma positive for CD5. Mediastinal radical radiotherapy (60 Gy) was performed postoperatively. The patient was followed for 17 months without any evidence of recurrence or metastasis.

Successful treatment of advanced thymic carcinoma with lymph node and pleural metastases: A case report

Thymic carcinoma is a rare type of cancer that is more aggressive and is associated with a poorer prognosis compared with thymoma. No definitive clinical management of this disease has been established to date. This report describes the 20-year clinical course of a 50-year-old male patient who was successfully treated for initially diagnosed stage IVb thymic carcinoma. Thymo-thymectomy combined with resection of the surrounding organs was performed on December 1995 with curative intent (R0) after neoadjuvant chemoradiotherapy. From June 2008 until present, four pleural and subclavicular lymph node metastases have been treated with chemotherapy, radiotherapy and surgery, followed by low-dose oral steroid therapy. The patient has remained disease-free for the last 20 months since the initiation of prednisolone treatment. Thus, multidisciplinary treatment may achieve long-term survival in patients with stage IVb thymic carcinoma.

Stereotactic ablative radiotherapy with CyberKnife for advanced thymic carcinoma: a case report

Thymic carcinoma is a rare but lethal mediastinal cancer. The optimal treatment for advanced thymic carcinoma is not yet established. This report is the first known of stereotactic ablative radiotherapy (sabr) with CyberKnife (Accuray, Sunnyvale, CA, U.S.A.) as definitive therapy for thymic carcinoma. The patient, a 70-year-old woman with thymic carcinoma, invasion into neighboring organs, and pleural metastases-underwent CyberKnife sabr at 40 Gy in 5 fractions for two lesions, one in the thymus and one in the right paraspinal pleura. After 61 months of observation, a partial response was observed in the irradiated fields. However, disease progression in the non-irradiated pleura was noted. The patient underwent salvage CyberKnife sabr for the four initially nonirradiated pleural lesions. Computed tomography images obtained 10 months after the salvage therapy revealed a partial response. The patient is living, with progression-free irradiated lesions and no radiation-related toxicity. CyberKnife sabr is feasible for patients who are unable to undergo either surgery or conventionally fractionated radiation therapy.

Chemotherapy with gemcitabine plus cisplatin in patients with advanced thymic squamous cell carcinoma: Evaluation of efficacy and toxicity

Background

Squamous cell carcinoma of the thymus is a rare thymic epithelial neoplasm that tends to widely metastasize at initial presentation. Because of its rarity, the optimal chemotherapeutic regimen remains uncertain. A gemcitabine and cisplatin regimen has shown promising efficacy in the treatment of other squamous cell carcinomas. We assessed the efficacy and toxicity of this regimen in patients with advanced thymic squamous cell carcinoma.

Methods

Between January 2003 and December 2012, 13 patients with untreated or unresectable recurrent thymic squamous cell carcinomas, who were treated with gemcitabine and cisplatin, were retrospectively analyzed. The endpoints in this study were clinical response rate, disease control rate, progression‐free survival, and overall survival. Significant hematological and non‐hematological toxicities were also assessed.

Results

Three patients were in Masaoka stage IVa and 10 were in stage IVb. The median number of treatment cycles for the present chemotherapy regimen was four. The clinical response and disease control rates were 61.5% and 92.3%, respectively. The median progression‐free and median overall survival rates were 14.5 months (95% confidence interval, 9.2–19.8 months) and 50.7 months (95% confidence interval, 24.9–76.5 months), respectively. Grade 3/4 hematological toxicities were observed in seven (53.8%) patients, and non‐hematological toxicities were mild.

Conclusion

This retrospective analysis demonstrated that gemcitabine plus cisplatin was active against advanced thymic squamous cell carcinoma with manageable toxicity. Gemcitabine may be a novel and alternative agent for advanced thymic squamous cell carcinoma.

Unusual combined thymic mucoepidermoid carcinoma and thymoma: a case report and review of literature

BACKGROUND

In rare condition, combined thymic epithelial tumors showing either type A or type B thymomas areas combined with thymic carcinoma components may occur in thymus. Mucoepidermoid carcinoma (MEC) of the thymus is rare in thymic carcinoma, and so far there is no report to describe a combined epithelial tumor of thymus with MEC component. We report an unusual case of combined thymic MEC/type B2 thymoma in a middle-aged male occurring in a mass of anterior mediastinum.

CASE REPORT

A 51-year-old Chinese male patient presented with a 6-month history of right ptosis and progressive muscle weakness. Computed tomography (CT) examination revealed a solitary, well-circumscribed mass was in the anterior mediastinum with mild heterogeneous enhancement. Histologically, the mass contained two separated components and displayed typically histological features of low-grade MEC and type B2 thymoma, respectively. There was no gradual transition of these two components observed in mass, and no enlarged lymph node was found in the surrounding tissues. A diagnosis of combined thymic MEC/type B2 thymoma was made. The patient received thymectomy to resect the mass totally. After surgery, chemotherapy with regiments of cisplatin and mitomycin, and radiotherapy of the main tumor bed were performed on the patient. There was no evidence of tumor recurrence during the period of 12 months follow-up.

CONCLUSION

To our best knowledge, this is the first report of combined thymic epithelial tumor with MEC component. Although this tumor is rare, the diagnosis of a thymic MEC should be taken into consideration when a combined epithelial tumor is occasionally encountered in thymus.

VIRTUAL SLIDES

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/9721397571157894.

Invasion of the great vessels or atrium predicts worse prognosis in thymic carcinoma

Purpose

We evaluated treatment outcomes of thymic carcinomas to determine prognostic factors for survival.

Materials and Methods

Between May 1988 and May 2009, 41 patients had pathologic diagnosis of thymic carcinoma in Seoul National University Hospital, Seoul, Korea. Of these, 40 patients were followed up to 188 months after treatment. The mean age of all patients was 58.3 years and male to female ratio was 23 to 17.

Results

Among 30 patients who underwent surgical resection, 26 achieved R0 resection and postoperative radiotherapy (PORT) was performed in 22 patients (73%). Various chemotherapeutic regimens were given with local treatment modalities, surgery and/or radiotherapy, in 12 patients. The 5-year locoregional control (LRC), distant metastasis-free survival, progression-free survival (PFS), and overall survival were 79.4%, 53.0%, 42.6%, and 63.6%, respectively. Patients with Masaoka stage I or II showed excellent prognosis of 5-year PFS around 90%. In advanced stages, invasion of the great vessels or atrium by thymic carcinomas was negative prognostic factor for PFS in univariate analysis. Lymph node involvement was statistically significant factor for LRC and PFS. Local or regional recurrence was infrequent after surgical resection followed by PORT, while distant metastasis was the major component of treatment failure.

Conclusion

Complete resection followed by PORT provided remarkable local control without severe acute toxicities in patients with stage II and favorable stage III thymic carcinoma. Invasion of the great vessels or atrium was statistically significant prognostic factor for PFS.

Chemotherapy for thymic carcinoma and advanced thymoma in adults

BACKGROUND

Thymic carcinoma or advanced thymoma is a rare cancer of the thymus gland that tends to be aggressive and infiltrate neighbouring organs, making total resection very difficult. Induction or adjuvant chemotherapy, or both, are often used in a multimodality approach to treat people affected by this condition, but the effectiveness of chemotherapy for thymic carcinoma or advanced thymoma remains uncertain.

OBJECTIVES

To assess the role of chemotherapy in adults with thymic carcinoma or advanced thymoma.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL 2012, Issue 7), MEDLINE (accessed via Ovid from 1966 to July 2012), EMBASE (accessed via Ovid, from 1980 to July 2012), Latin American and Caribbean Literature on Health Sciences (LILACS), the Chinese Biological Medicine Database (CBM, 1978 to July 2012), China National Knowledge Infrastructure (CNKI, 1980 to July 2012) and the Chinese scientific periodical database VIP Information (VIP, 1989 to July 2012). There was no language restriction in searching for studies.

SELECTION CRITERIA

We planned to include randomised controlled trials (RCTs) of  trials using chemotherapy (either single-agent or combination chemotherapy plus surgery, radiotherapy or not) for thymic carcinoma and/or advanced thymoma. We planned to include all adults (aged 18 years and over) diagnosed with thymic carcinoma and/or with Masaoka stage III or IV thymic tumours. The intended primary outcomes were overall survival (OS) and progression-free survival (PFS).

DATA COLLECTION AND ANALYSIS

Two review authors independently evaluated the search results according to the inclusion and exclusion criteria. There were no studies identified for inclusion and therefore no data extraction was completed.

MAIN RESULTS

No RCTs were eligible for inclusion in this review. We report details of excluded prospective studies in an additional table and try to provide some useful evidence regarding current practice.

AUTHORS' CONCLUSIONS

There were no RCTs eligible for inclusion in this review. In current practice the most common regimen for adult patients with thymic carcinoma or advanced thymoma is cisplatin-based chemotherapy. Considering the condition is rare, it is suggested that an international group is set up to organise and evaluate prospective collection of data from cohorts of patients to inform current clinical practice.

Early-stage thymic carcinoma: is adjuvant therapy required?

Although the prognosis of advanced thymic carconoma remains poor, previous reports have shown survival rates of 70% to 100% in patients with Masaoka stage I or stage II of the disease who were treated with surgery followed by adjuvant therapy. However, the role of adjuvant therapy in these stages is controversial. We retrospectively evaluated the outcome of 4 patients with Masaoka stage II thymic carcinoma who were treated with surgery alone between 1992 and 2008. No patient had stage I of the disease. Primary tumors were preoperatively evaluated by chest X-ray and computed tomography. Needle biopsy was not performed because the tumors were clinically diagnosed as noninvasive thymomas. The largest diameter of the primary tumor was 65 mm. Mediastinal lymphadenopathy was not detected by computed tomography. All patients underwent transsternal thymectomy. Mediastinal lymph node dissection was not performed. None of the patients received adjuvant chemotherapy and/or irradiation. Histopathologic examination revealed squamous cell carcinoma in 3 patients and undifferentiated carcinoma in one. Pathologic invasion to the adjacent organs or lymph node metastasis was not detected. All patients were alive and free from relapse at a follow-up of 72 months (range, 12-167 months). Radical resection without adjuvant therapy could be a treatment option for early Masaoka stage thymic carcinoma with low-grade histology.

Radiotherapy for thymic neoplasms

The role of radiotherapy in the treatment of thymoma and thymic carcinoma has been evaluated by many investigators over the past two decades. The low incidence of these neoplasms has limited most published studies to small series spanning long time intervals or population-based studies. The exact indications and protocols for the use of radiotherapy as a part of the multidisciplinary approach to thymoma and thymic carcinoma are still unclear. However, a review of recent literature shows potential benefits for certain patients based on stage and grade of disease as well as the extent of surgical resection.

Response to sorafenib in cisplatin-resistant thymic carcinoma: a case report

Platinum-based chemotherapy regimens are often recommended for patients with unresectable thymic carcinoma. In more than 60 cases, however, the systemic chemotherapy provides little benefit. In this report, we described a case of advanced KIT- and VEGF-positive thymic carcinoma with liver and lung metastasis. The patient, a 46-year-old man, exhibited a resistance to cisplatin-based chemotherapy, but responded to the treatment with sorafenib, a molecular target-based therapy. After 4 months of sorafenib therapy, his lung and liver metastases as well as the mediastinal tumor shrank dramatically. Moreover, the tumors showed stable disease for at least 9 months. To the best of our knowledge, it is the first report about a response of advanced thymic carcinoma to sorafenib. The preliminary study suggested that molecular target-based therapy could be an alternative treatment to those chemotherapy-refractory patients.

Videothoracoscopic resection of encapsulated thymic carcinoma: retrospective comparison of the results between thoracoscopy and open methods

BACKGROUND

Although videothoracoscopic (VTS) resection of thymoma has been reported to be a less invasive technique than open sternotomy, the usefulness of this method in the treatment of encapsulated thymic carcinoma has not yet been evaluated. We retrospectively compared the VTS and open methods (median sternotomy) to investigate whether VTS resection could be performed as successfully as open surgery to treat resectable thymic carcinoma.

METHODS

Between November 2002 and March 2007 a retrospective review was made of eight patients (four women and four men) with Masaoka stage I and II encapsulated thymic tumor. Four patients (the VTS group) underwent tumor resection by means of a three-port endoscopic technique. The other four patients (the open group) underwent tumor excision via a standard sternotomy approach. The resected thymic carcinoma tissues were all confirmed by histopathological examination.

RESULTS

No patient died nor did any major morbidity or recurrence occur during the mean follow-up period of 3.76 +/- 1.43 years. The open group sustained more blood loss (246.3 ml more) and pleural drainage time (5.7 days more), and were hospitalized for a longer period (12.5 days more). However in the open group the tumor size was larger (38.6 cm(3 )more ) and the mean follow-up time was longer (1.4 years more).

CONCLUSION

These results have encouraged us to treat more patients with encapsulated thymic carcinoma by means of VTS resection.

Response of a thymic mucoepidermoid carcinoma to combination chemotherapy with cisplatin and irinotecan: A case report

A chemotherapeutic regimen for advanced thymic carcinoma has not yet been established. We describe a patient with advanced thymic mucoepidermoid carcinoma who achieved a complete response to combination chemotherapy with cisplatin (Randa) and irinotecan hydrochloride (Campto). A 74-year-old man was admitted to our hospital because of chest pain, general fatigue, appetite loss and weight loss. Chest computed tomography examinations revealed an anterior mediastinal tumour (5.5cmx3.5cmx9.5cm) that had invaded the subcutis through the sternum. The patient was treated with three courses of cisplatin and irinotecan hydrochloride followed by radiotherapy; he has since exhibited a complete response for 3 months.

Radiation therapy in the management of thymic tumors

Thymic tumors including thymomas, thymic carcinomas, and thymic carcinoid tumors, are relatively infrequent. These tumors with a wide spectrum of histological and biological features may exhibit an indolent clinical course (thymomas) or manifest an aggressive behavior (thymic carcinoma) with a high risk of relapse and metastasis. Successful management of these tumors depends on accurate diagnosis, thorough staging, proper assessment of patient health status, and selection of treatment modality. Surgery remains the mainstay of therapy whereas radiation therapy plays an important role in subtotally resected or unresectable cases. The risk of side effects and late sequelae is generally low when proper radiation technique is employed. This review examines the current role of radiation therapy in the management of these tumors.

Thymic carcinoma: state of the art review

Thymic carcinoma is a rare neoplasm with distinct clinical and pathological characteristics. The prognosis is often poor with an aggressive course that belies its numerical rarity. Potentially prognostic factors for survival include histopathologic grade, clinical stage, and resectability of the tumor. Five-year survival rates for all patients are approximately 30-50%, with a significant survival time differential between low-grade and high-grade neoplasms. Owing to the paucity of cases, optimal management of thymic carcinoma has yet to be defined. At present, a multimodality approach involving aggressive surgical resection, platinum-based combination chemotherapeutic interventions, and radiotherapy represent the preferred therapeutic approach. Though our knowledge remains somewhat speculative at present, several scientific, technological and therapeutic innovations may have a potentially significant impact on the future of this disease.

Postoperative radiotherapy in thymic carcinoma: treatment results and prognostic factors

PURPOSE

To analyze the treatment results and prognostic factors of patients with primary thymic carcinoma treated by total or subtotal tumor resection followed by radiotherapy alone.

METHODS AND MATERIALS

Between October 1987 and October 1997, 26 patients with thymic carcinoma were treated with complete or incomplete surgical resection and postoperative adjuvant irradiation without chemotherapy. The radiation was delivered with 10-MV X-ray given 5 days per week at 1.8 to 2 Gy per fraction. Total doses ranged from 40 to 70 Gy. All patients had at least 40 months of follow-up.

RESULTS

The 5-year overall survival rate, local control rate, and distant metastasis-free rate were 77%, 91%, and 57%, respectively. Several prognostic factors, including sex, age, extent of resection (total resection vs. subtotal resection), Masaoka staging (early Stage I + II vs. advanced Stage III + IV), pathology (low-grade vs. high-grade), and postoperative radiation dose (> or =60 Gy vs. <60 Gy), were evaluated in univariate analysis. The Masaoka staging system was the only statistically significant predictor in overall survival rate (p = 0.0482) and distant metastasis-free rate (p = 0.0193).

CONCLUSIONS

The Masaoka staging system is the most important prognostic factor in primary thymic carcinoma patients receiving postoperative radiotherapy alone. For resectable tumors, surgery and postoperative radiotherapy can achieve good local control, but the distant metastatic rate is still high. Further investigation of more effective chemotherapy is needed.