Radiotherapy for thymic neoplasms. J Thorac Oncol. 2010;5:S327-S335. [PMID: 20859128 DOI: 10.1097/jto.0b013e3181f20ec4]

Thymic Carcinoma Presenting as a Mediastinal Mass Resembling a Cardiac Tumor

Thymoma and thymic carcinomas are a few of the rarest malignancies seen in humankind. They are mostly seen in the Asian population, many of which are reported in the Southeast Asia region like Japan, China, Vietnam, etc. They usually can be a sequela of other underlying conditions such as myasthenia gravis or some unknown mutations that express later in life.   Our patient is a young 41-year-male, a healthy and active individual who presented for evaluation of acute shortness of breath, two months after recovering from SARS-CoV-19 infection. His shortness of breath progressed while on oxygen and diuretics, a Point of Care Ultrasound (POCUS) showed cardiac tamponade and moderate pleural effusion. A Computerized Tomographic (CT) scan of the chest/abdomen/pelvis showed cardiomegaly, pleural effusion, and a mass abutting the heart. A pericardiocentesis revealed malignant cells. Thymic carcinoma was confirmed with a core biopsy and the patient was initiated on treatment rapidly to help improve symptoms and contain the growing mass.  .

Comparison of radiotherapy techniques in patients with thymic epithelial tumor who underwent postoperative radiotherapy

PURPOSE

This retrospective study aimed to compare clinical outcomes and dosimetric parameters between radiation therapy (RT) techniques in patients with thymic epithelial tumor (TET).

MATERIALS AND METHODS

From January 2016 to December 2020, 101 patients with TET received adjuvant RT (median, 52.8 Gy; range, 48.4 to 66.0). Three different RT techniques were compared: three-dimensional conformal RT (3D-CRT; n = 59, 58.4%), intensity-modulated RT (IMRT; n = 23, 22.8%), and proton beam therapy (PBT; n = 19, 18.8%).

RESULTS

The median age of the patients and the follow-up period were 55 years (range, 28 to 79) and 43.4 months (range, 7.7 to 77.2). Patients in the PBT group were of the youngest age (mean age, 45.4 years), while those in IMRT group had the largest clinical target volume (mean volume, 149.6 mL). Patients in the PBT group had a lower mean lung dose (4.4 Gy vs. 7.6 Gy vs. 10.9 Gy, respectively; p < 0.001), lower mean heart dose (5.4 Gy vs. 10.0 Gy vs. 13.1 Gy, respectively; p = 0.003), and lower mean esophageal dose than patients in the 3D-CRT and IMRT groups (6.3 Gy vs. 9.8 Gy vs. 13.5 Gy, respectively; p = 0.011). Twenty patients (19.8%) showed disease recurrence, and seven patients (6.9%) died. The differences in the survival rates between RT groups were not statistically significant.

CONCLUSION

In patients with TET who underwent adjuvant RT, PBT resulted in a lower dose of exposure to adjacent organs at risk. Survival outcomes for patients in PBT group were not significantly different from those in other groups.

GOECP/SEOR radiotherapy guidelines for thymic epithelial tumours

Thymic epithelial tumours (TET) are rare, heterogeneous neoplasms that range from resectable indolent tumours to aggressive thymic carcinomas with a strong tendency to metastasize. The pathological diagnosis is complex, in part due to the existence of several different classification systems. The evidence base for the management of TETs is scant and mainly based on non-randomised studies and retrospective series. Consequently, the clinical management of TETs tends to be highly heterogenous, which makes it difficult to improve the evidence level. The role of technological advances in the field of radiotherapy and new systemic therapies in the treatment of TETs has received little attention to date. In the present clinical guidelines, developed by the GOECP/SEOR, we review recent developments in the diagnosis and classification of TETs. We also present a consensus-based therapeutic strategy for each disease stage that takes into consideration the best available evidence. These guidelines focus primarily on the role of radiotherapy, including recent advances, in the management of TETs. The main aim of this document is to promote the standardisation of clinical practice and lay the foundations for future studies to clarify the main unresolved questions related to the optimal management of TET.

Thymic Epithelial Neoplasms: Tumor-Node-Metastasis Staging

Thymic epithelial neoplasms are a group of malignant tumors that includes thymoma, thymic carcinoma, and thymic neuroendocrine tumors. Although several staging systems have been developed over the years for use with these cancers, they have been interpreted and implemented in a nonuniform manner. Recently, the International Association for the study of Lung Cancer and the International Thymic Malignancy Interest Group developed a tumor-node-metastasis staging system that has been universally accepted and correlates with patient survival and outcomes. Although pathologic staging is determined by histologic examination of the resected tumor, imaging plays an important role in clinical staging and is important for informing therapeutic decisions.

The Outcome and CT Findings of Low-Dose Intensity Modulated Radiation Therapy with SQAP in a Cat with Thymoma

A 9-year-old male intact domestic cat weighing 4.6 kg was referred for tachypnea. A large mass was visible in computed tomography (CT) scans of the thoracic cavity. A histopathological evaluation of the mass was consistent with thymoma. The cat was treated with 2 × 8 Gy intensity modulated radiation therapy and sulfoquinovosyl acyl propanediol (SQAP). Post radiation therapy (RT), the tumor structure appeared cystic in the CT, and the tumor volume decreased by approximately 80% after aspiration than that before aspiration. The tumor was removed surgically. RT treatment with SQAP made it possible to treat the thymoma with a low total radiation dose.

Prognostic Factor of Completely Resected and Pathologic T3 N0 M0 Thymic Epithelial Tumor

BACKGROUND

A multiinstitutional study was conducted to analyze prognosticators of completely resected and pathologic T3 N0 M0 (pT3 N0 M0) stage thymic epithelial tumors.

METHODS

A total of 607 patients with surgically treated thymic epithelial tumors between June 1988 and December 2017 were enrolled. A Cox proportional hazards model and an inverse probability of treatment weighting-adjusted analysis using the propensity score were performed.

RESULTS

A total of 394 patients with thymoma and 130 patients with thymic carcinoma underwent complete tumor resections. Forty-one thymomas and 49 thymic carcinomas were confirmed as pT3 N0 M0 stage tumors. Postoperative adjuvant radiotherapy was associated with improved disease-free and overall survival in patients with thymoma (hazard ratio [HR], 0.40; 95% confidence interval [CI], 0.23 to 0.69; and HR, 0.24; 95% CI, 0.11 to 0.52, respectively) and in patients with thymic carcinoma (HR, 0.15; 95% CI, 0.07 to 0.33; and HR, 0.12; 95% CI, 0.05 to 0.31, respectively). Although lung invasion was associated with poor disease-free survival (HR, 3.28; 95% CI, 1.90 to 5.89) and overall survival (HR, 2.60; 95% CI, 1.21 to 6.07), male sex (HR, 1.88; 95% CI, 1.10 to 3.18), older age (HR, 2.77; 95% CI, 1.29 to 5.70), and advanced histologic features (HR, 3.84; 95% CI, 1.42 to 14.51) were associated with poor overall survival in patients with pT3 N0 M0 thymoma. Adjuvant chemotherapy was associated with improved disease-free survival (HR, 0.11; 95% CI, 0.03 to 0.41) and overall survival (HR, 0.11; 95% CI, 0.06 to 0.20) in patients with pT3 N0 M0 thymic carcinoma with superior vena cava or innominate vein invasion.

CONCLUSIONS

Postoperative radiotherapy was associated with improved survival in patients with pT3 N0 M0 thymic epithelial tumors. Lung invasion was associated with poor survival in patients with pT3 N0 M0 thymoma. Adjuvant chemotherapy was associated with improved survival in patients with pT3 N0 M0 thymic carcinoma with superior vena cava or innominate vein invasion.

The role of salvage radiotherapy in recurrent thymoma

Purpose

To explore the role of salvage radiotherapy (RT) for recurrent thymoma as an alternative to surgery.

Materials and Methods

Between 2007 and 2015, 47 patients who received salvage RT for recurrent thymoma at Yonsei Cancer Center were included in this study. Recurrent sites included initial tumor bed (n = 4), pleura (n = 19), lung parenchyma (n = 10), distant (n = 9), and multiple regions (n = 5). Three-dimensional conformal and intensity-modulated RT were used in 29 and 18 patients, respectively. Median prescribed dose to gross tumor was 52 Gy (range, 30 to 70 Gy), with equivalent doses in 2-Gy fractions (EQD₂). We investigated overall survival (OS), progression-free survival (PFS), and patterns of failure. Local failure after salvage RT was defined as recurrence at the target volume receiving >50% of the prescription dose.

Results

Median follow-up time was 83 months (range, 8 to 299 months). Five-year OS and PFS were 70% and 22%, respectively. The overall response rate was 97.9%; complete response, 34%; partial response, 44.7%; and stable disease, 19.1%. In multivariate analysis, histologic type and salvage RT dose (≥52 Gy, EQD₂) were significantly associated with OS. The high dose group (≥52 Gy, EQD₂) had significantly better outcomes than the low dose group (5-year OS: 80% vs. 59%, p = 0.046; 5-year PFS: 30% vs. 14%, p=0.002). Treatment failure occurred in 34 patients; out-of-field failure was dominant (intra-thoracic recurrence 35.3%; extrathoracic recurrence 11.8%), while local failure rate was 5.8%.

Conclusion

Salvage RT for recurrent thymoma using high doses and advanced precision techniques produced favorable outcomes, providing evidence that recurrent thymoma is radiosensitive.

Patterns of Failure Following Postoperative Radiation Therapy Based on "Tumor Bed With Margin" for Stage II to IV Type C Thymic Epithelial Tumor

PURPOSE

The study purpose was to report failure patterns in Masaoka-Koga stage II to IV type C thymic epithelial tumor (TET) after postoperative radiation therapy (PORT) and to evaluate the suitability of PORT target volume confined to the "tumor bed only with margin."

METHODS AND MATERIALS

A retrospective review of 53 patients with stage II to IV type C TET was performed. The clinical outcomes, failure patterns in relation to PORT target volume, and prognostic factors were analyzed.

RESULTS

During a median follow-up period of 69 months, 14 deaths and 25 recurrences were observed. The 5-year rates of overall survival, disease-specific survival, and freedom from recurrence were 81.0%, 91.5%, and 49.7%, respectively. The failure patterns in relation to PORT target volume were in-field failure in 2 patients (3.8%), marginal in 2 (3.8%), and out of field in 23 (43.4%), respectively. The most common failure site was the pleura (12 patients), followed by the lung parenchyma (8 patients). Relapse involving the regional lymph nodes was observed in 6 patients, of whom 4 had synchronous distant failure and only 2 had isolated ipsilateral supraclavicular lymph node failure.

CONCLUSIONS

The policy of PORT target volume confined to only the tumor bed seems reasonable in treating patients with stage II to IV type C TET. The development of a more effective systemic therapy regimen is warranted.

Chemotherapy with carboplatin and paclitaxel after failure of primary chemotherapy for advanced thymic carcinoma. A report of three cases and review of the literature

For patients with inoperable thymic carcinoma, multidrug chemotherapy containing cisplatin and an anthracycline is often used as first-line chemotherapy. A commonly applied regimen is cisplatin + doxorubicin + vincristine + cyclophosphamide (ADOC). There are relatively few reports on the use of carboplatin and paclitaxel as first-line chemotherapy for thymic carcinoma. In addition, little is known about its efficacy as second-line chemotherapy in patients with advanced thymic carcinoma. We here report on three patients with thymic carcinoma who were treated with carboplatin and paclitaxel as second-line chemotherapy after failure of ADOC. According to the Response Evaluation Criteria in Solid Tumors version 1.1, one patient achieved a partial response and two patients achieved stable disease. The median progression-free survival was 6.7 months and the median overall survival exceeded 3 years. Toxicities were well tolerated. Chemotherapy with carboplatin and paclitaxel appears to be effective as second-line chemotherapy for some persons with thymic carcinoma who fail ADOC.

Prospective Study of Stereotactic Body Radiation Therapy for Thymoma and Thymic Carcinoma: Therapeutic Effect and Toxicity Assessment

Stereotactic body radiation therapy (SBRT) is an important modality in treatment of tumors. We hypothesized that SBRT can achieve excellent local control with limited toxicity in patients with thymic tumors. A single-institution prospective study was performed with 32 patients who underwent SBRT of thymoma and thymic carcinoma between 2005 and 2014. Thirty-two patients including 39 target lesions were analyses in this study. Almost half of the patients (46.9%) were type C by histopathology and more than half (56.3%) were classified into stage IVA or IVB. The median dose of SBRT for gross tumor volume (GTV) was 56 Gy (range 49–70 Gy). Results showed that the response rate was 96.9% after SBRT and the median tumor shrinkage rate was 62.2% (range 3.8–100%). For the patients with both stage II–III and type A-B (n = 6), the median PFS was 28 months. In-field failure was only observed in 4 patients, and outside-field failure was seen in 2 patients. The local control rate was 81.25%. Patients treated with SBRT had an excellent local control with mild toxicities, which suggests that SBRT is feasible for the patients with thymic tumors who are unable to undergo either surgery or conventionally fractionated radiation therapy.

[Thymus cancers: A clinical observation]

INTRODUCTION

Thymic tumors including thymomas, thymic carcinomas, and thymic carcinoid tumors are rare tumors with an incidence of 0.13/100,000.

MATERIALS AND METHODS

A literature search was performed to identify recent findings on epidemiology, classification, and various therapeutic approaches.

RESULTS

These tumors with a wide spectrum of histologic and biologic features may be clinically unapparent for a long time or show a very aggressive behavior with local invasion and distant metastases. Surgical resection is the mainstay in stage I and II thymomas, whereas in stage III thymomas and in thymomas with pleural dissemination surgery in context of a multimodal treatment should be discussed. Thymic tumors are chemoreactive. Targeted therapies show poor results and should only be considered in the palliative situation after failure of chemotherapy.

CONCLUSION

The new TNM (T: tumor, N: node, M: metastasis) classification of thymic tumors will help to identify the best treatment options.

[Retrospective analysis of 50 thymic epithelial tumors in Rennes university hospital]

BACKGROUND

Thymic epithelial tumors (TET), including thymomas and thymic carcinomas, are rare and characterized by very different evolutionary patterns depending on histology and invasion stage. The therapeutic management is not well defined but is a subject of increasing interest. The descriptive and analytic objectives of this retrospective monocentric study were to analyze the clinical characteristics of patients with TET, and to assess the management of these tumors in our centre.

METHODS

Adult patients with TET managed in the Rennes university hospital in the period 2000-2011 were selected via the pathology department. Their clinical and pathological features and survival were analyzed retrospectively.

RESULTS

Fifty TET were retrieved (46 thymomas and 4 thymic carcinomas). Their clinical and histological features and their invasion stages were concordant with published studies. Their diagnostic and therapeutic managements were also in accordance with current guidelines. In univariate analysis, myasthenia and surgery were associated with better survival rates.

CONCLUSION

Management of TET in Rennes university hospital is in accordance with guidelines.

Advances in thymic carcinoma diagnosis and treatment: a review of literature

Thymomas account for up to 50 % of anterior mediastinal neoplasms with an incidence of 0.13 per 100,000 person-years in the USA. Thymic carcinoma is a rare malignancy of the thymus gland distinguished from thymomas as it has a more invasive and metastasizing potential conferring poor prognosis. Due to the rarity of thymic carcinoma and the great variety of its histological subtypes, there is no solid evidence on optimal staging, imaging and treatment guidelines. Herein, we systematically review the literature on current clinical practice with regard to diagnostic evaluation, histopathological assessment, management and treatment of squamous thymic carcinoma.

Thymoma: a population-based study of the management and outcomes for the province of British Columbia

INTRODUCTION

Thymomas are rare neoplasms with variable clinical behavior. Our primary study aim was to analyze treatment practices and outcomes in a population-based cohort of thymoma patients. We hypothesized that stage I and II thymomas would have high cure rates with resection and adjuvant radiation, whereas locally advanced cases would benefit from multimodality therapy.

METHODS

All patients, diagnosed with thymoma or thymic carcinoma in British Columbia between 1994 and 2009, were identified using the British Columbia Cancer Agency Registry. Chart review was used to collect demographic and treatment data. Detailed pathology review was performed using the World Health Organization classification.

RESULTS

One hundred and seventy-one patients were identified for analysis. The 5-year overall survival was 93.3%, 88.7%, 74.6%, 43.4% for stages I, II, III, and IV, respectively. Survival varied significantly among patients with thymoma compared with thymic carcinoma. In patients with stage II disease, adjuvant radiation did not confer an overall survival or recurrence-free survival benefit. Seventy-five patients had locally advanced disease. There was practice variation in treatment of these patients. Patients with thymoma undergoing trimodality treatment had a 5-year median overall survival of 80%, whereas patients with thymic carcinoma had poor outcomes despite aggressive treatment.

CONCLUSIONS

Survival rates in this population-based series were comparable to those in previously published reports. The ideal management of thymic tumors involves a multidisciplinary approach, particularly in locally advanced disease and selection of patients for adjuvant radiation therapy.