Clinical and pathologic predictors of survival in patients with thymoma

Concurrent metastatic thymic carcinoma and postirradiation sarcoma

We present a case of concurrent metastatic thymic carcinoma and postirradiation sarcoma in the same lobe of the lung in a woman who had received partial resection of thymic carcinoma with chemoradiotherapy 11 years ago. One tumor showed similar histology to the previous carcinoma. The other tumor was a pleomorphic sarcoma, suggestive of a postirradiation sarcoma. Irradiation-induced sarcomas are rare and have not been reported in patients with thymic carcinoma. This case may serve as a model in considering the possibility of postirradiation sarcoma for patients encountering recurrent masses with the history of radiotherapy for thymic carcinoma several years ago.

Standard outcome measures for thymic malignancies

Thymic malignancies present particular issues due to the pace of disease progression, patterns of recurrence, and causes of death that make nuances of how outcomes are reported particularly important. The relatively limited number of patients also creates a challenge to glean as much as possible from the available experience, but risks over-interpretation and potentially misleading conclusions. Therefore the International Thymic Malignancy Interest Group has developed a set of standards for reporting of outcome measures of clinical studies, which have been adopted for collaborative projects undertaken by the organization. Widespread adoption of this baseline will enhance the ability to compare results from different series.

Management of stage I and II thymoma

With a knowledgeable assessment of the clinical presentation and demographic and radiologic characteristics, most thymomas can be reliably identified preoperatively without the need for a biopsy. Surgery is the mainstay of treatment for stage I and II thymoma. The rate of complete resection is essentially 100% by open techniques, and recurrences are rare. A complete thymectomy via a sternotomy is the standard approach. Adjuvant radiotherapy after a complete resection does not appear to be of benefit. In the rare event of a recurrence, an aggressive approach should be taken with re-resection whenever possible.

Surgical management of stage III thymic tumors

Thymic tumors are classified as stage III when they clearly invade the surrounding structures: pericardium, great vessels (superior vena cava, innominate veins, ascending aorta, and main pulmonary artery), lung parenchyma, phrenic nerves, and chest wall. Surgical treatment with or without induction therapy should always aim to complete resection removing en bloc all the involved structures. Also, extended procedures are justified because only R0 resection allows long-term survival.

Prediction of thymoma histology and stage by radiographic criteria

Thymic epithelial tumors, such as thymomas and thymic carcinomas, are the most common primary neoplasms of the mediastinum. In 1999, the World Health Organization (WHO) proposed a consensus classification of thymic epithelial tumors based on the morphology of the epithelial cells and the ratio of lymphocytes to epithelial cells, which was revised in 2004. The latest classification system stratifies thymic epithelial tumors into six categories: types A, AB, B1, B2, B3, and thymic carcinoma. This article describes the prediction of thymoma histology and stage on the basis of radiographic criteria by reviewing the following: the WHO histologic classification of thymic epithelial tumors, the clinical staging of thymomas based on prognosis, and the radiographic appearance of thymomas according to the WHO histologic classification.

Staging system of thymoma

INTRODUCTION

Thirty years have gone by since the Masaoka staging system of thymoma was proposed in 1981. Although the Masaoka staging system has been accepted by many surgeons and pathologists, some proposals of revision and improvements have been suggested. At this time, I reinvestigated the Masaoka staging system based on the recent follow-up study of the thymomas resected at Nagoya City University.

METHODS

Using the follow-up results of 211 thymomas in Nagoya, I analyzed the following aspects: (1) evaluation of the Masaoka staging system as a prognostic factor in the Nagoya series and (2) critical assessment of the proposals of revision to the Masaoka staging system.

RESULTS

(1) Univariate analysis showed that Masaoka stages were significantly prognostic for overall survival (p < 0.0001). (2) The difference of survivals between stage I and II was not significant, but progression-free survival of stage I was 100% for up to 20 years, whereas one tumor death case in stage II was found. (3) Differences of survival between the cases with and without great vessel invasion in stage III were not significant. (4) Prognosis of N tumors was yet better defined.

CONCLUSION

(1) The Masaoka staging system remains a valuable prognostic factor. (2) Combination of stage I with II and separation of stage III into subgroups are not recommended. (3) At the moment, it is better to include N tumors in stage IVb.

Thymoma with coexisting undifferentiated pleomorphic sarcoma: a case report

We report here a case of thymoma simultaneously associated with undifferentiated pleomorphic sarcoma. A 45-year-old male presented with axillary lump. Radiographic studies showed a mediastinal mass. On fine needle aspiration cytology and histopathological examination, a diagnosis of thymoma with coexisting undifferentiated pleomorphic sarcoma was made. Although thymomas are associated with many extrathymic malignancies, it's association with undifferentiated pleomorphic sarcoma is rare. This case is being reported on to reinforce that clinicians should bear in mind the possibility of extrathymic malignancies in patients with thymomas.

[Cytoreductive surgery and hyperthermic intrathoracic chemotherapy perfusion]

Recently cytoreductive surgery of primary and secondary pleural tumors has been combined with hyperthermic intrathoracic chemotherapy perfusion (HITHOC) for better local tumor control. In comparison to simple instillation of chemotherapeutic agents into the pleural cavity, the combination of surgical resection of pleural tumors and simultaneous HITHOC seems to be a more effective treatment. Intra-operative perfusion allows an improved distribution of the drug in the pleural space and a higher local concentration of the chemotherapeutic agents in contrast to systemic chemotherapy. Additional advantages of HITHOC are a better response to chemotherapeutic agents and synergistic antineoplastic effects. A prerequisite for safe application of HITHOC is compliance with safety regulations. Due to the reduction in morbidity and mortality this new concept is a valuable alternative for selected patients who do not undergo radical resection (e.g. extrapleural pneumonectomy). HITHOC is an additional therapeutic option in the multimodal treatment of patients with primary or secondary tumors of the pleura.

Tumors of the mediastinum and chest wall

Primary tumors of the mediastinum and chest wall comprise a diverse group of conditions with a wide range of presentations. A thorough knowledge of thoracic anatomy is essential for appropriate diagnosis and treatment. Given their proximity to critical structures, treatment of these tumors is often challenging. Although surgery is the mainstay of therapy for most mediastinal and chest wall tumors, a multidisciplinary approach is valuable in many cases.

New predictors of response to neoadjuvant chemotherapy and survival for invasive thymoma: a retrospective analysis

BACKGROUND

Cell-cycle protein (p27, p21, and p53) expression can predict response to neoadjuvant chemotherapy and prognosis in some neoplasms. This study evaluated whether these markers could also be effective in invasive thymoma during a multimodality treatment.

METHODS

Between 1989 and 2008, 33 patients with invasive thymoma underwent surgical resection after neoadjuvant chemotherapy. Expression of p27, p21, and p53 was assessed using immunohistochemistry in specimens retrieved pre and post chemotherapy. Factors influencing response to neoadjuvant chemotherapy and survival were investigated by univariate and multivariate analysis. Good response was defined as complete disappearance of tumor at imaging or necrosis >90% at pathologic studies.

RESULTS

Twelve patients disclosed an imaging good response. Complete resection was possible in 17 patients, 9 of whom had presented imaging good response and 11 of whom had revealed pathologic good response. On univariate analysis both imaging and pathologic poor responses were significantly associated with incomplete resection (P = 0.04 and P = 0.03, respectively) and preneoadjuvant triple combination of p27 low, p21 low, and p53 high expressions (P = 0.001 and P < 0.0001, respectively), the last factor being the only one selected on logistic regression (P = 0.01 and P = 0.005, respectively). Long-term survival analysis was negatively influenced by triple combination of p27, p21, and p53 (P < 0.0001) and incomplete resection (P < 0.0001), which were also selected on Cox's regression (P = 0.004 and P = 0.02, respectively).

CONCLUSIONS

The triple combination of p27 low, p21 low, and p53 high expressions was the most significant predictor of imaging and pathologic poor responses to neoadjuvant chemotherapy in invasive thymoma. This combination together with incomplete resection was also the most significant negative predictor of long-term survival.

Thirty-five-year follow-up analysis of clinical and pathologic outcomes of thymoma surgery

BACKGROUND

The impact of myasthenia gravis on patients with thymoma is still controversial when perioperative and long-term outcomes are analyzed. With the unique opportunity of a 35-year follow-up in a single institution, thymomatous myasthenia gravis cohort, we investigated the influence of early and long-term clinical predictors.

METHODS

We reviewed a surgical series of 317 (1972 to 2007) patients with thymoma: clinical and pathologic features were analyzed as prognostic factors matched against the short- and long-term survival and recurrence rates.

RESULTS

Male to female ratio was 153:164; median age, 49 years. Myasthenia gravis coexisted in 276 patients (87.1%). Thymomas were classified according to the Masaoka (42.0% stage I, 32.2% stage II, 21.5% stage III, and 4.4% stage IV) and the World Health Organization (3.5% type A, 9.5% type AB, 19.2% type B1, 57.7% type B2, 8.2% type B3, and 1.9% thymic carcinoma) staging systems. The resection was complete in 295 patients (93.1%). Operative mortality and morbidity were respectively 1.6% and 7.6%. No differences were recorded in postoperative outcome stratifying for myasthenia gravis or comorbidities. Mean follow-up was 144.7 +/- 104.4 months. The overall 5-, 10-, 20-, and 30-year survival rates were 89.9%, 84.1%, 73%, and 58.6%, respectively. The completeness of resection (p < 0.001), the Masaoka staging (p = 0.010), and the World Health Organization classification (p < 0.001) all significantly influenced the long-term survival (univariate analysis). Only completeness of resection was significantly correlated with a better prognosis (p < 0.001) in multivariate analysis. Masaoka staging (p < 0.001) and World Health Organization classification (p < 0.001) significantly correlated with the disease-free survival in the univariate and multivariate analyses as significant prognostic factors (Masaoka, p < 0.001; World Health Organization, p = 0.011). Myasthenia gravis patients showed a better prognosis in terms of long-term survival (p = 0.046) and disease-free survival (p = 0.012) in the univariate analysis.

CONCLUSIONS

We confirm the evidence that the clinical staging and the histologic classification influence long-term survival. The presence of myasthenia gravis was not significantly related to operative outcome, but prolongs both long-term survival and disease-free survival.

Stage III thymic epithelial neoplasms are not homogeneous with regard to clinical, pathological, and prognostic features

INTRODUCTION

The main therapeutic approach to a Masaoka stage III thymic epithelial neoplasm (TEN) is surgical resection, and the 5-year survival rate is approximately 60%. According to the Masaoka staging system, invasion of neighboring organs is classified as stage III disease, regardless of the number of organs involved or the size of the tumor. We retrospectively analyzed the prognostic significance associated with the extent of disease in patients with Masaoka stage III TENs.

METHODS

From 1995 to 2006, 241 patients were identified with thymomas. Among these patients, 59 were diagnosed with Masaoka stage III disease. The patients with a stage III TEN were advised to have extended thymectomy with en bloc resection of the invaded structures as the initial treatment. The prognostic significance of the size, organs invaded, and other factors were analyzed.

RESULTS

The overall survival rates for the stage III patients were 83% and 64%, and the recurrence-free survival rates were 56% and 51%, at 5 and 8 years, respectively. Patients with a low-grade World Health Organization classification (p = 0.0202) or a complete resection (p < 0.0001) had a better overall survival. In addition, patients with tumors less than 6.5 cm (p = 0.0311) or with pericardium invasion (p = 0.0299) had a better recurrence-free survival. The patients with limited disease had a better prognosis for a recurrence-free survival than did patients with extensive disease (p = 0.0007).

CONCLUSIONS

Heterogeneous prognostic subgroups based on tumor size and organs invaded were identified in patients with Masaoka stage III TENs. Therapeutic plans, based on these subgroups, will potentially improve patient management and treatment outcomes.

The management of thymoma: a systematic review and practice guideline

INTRODUCTION

Thymoma is a rare tumor for which there is little randomized evidence to guide treatment. Because of the lack of high-quality evidence, a formal consensus-based approach was used to develop recommendations on treatment.

METHODS

A systematic refview of the literature was performed. Recommendations were formed from available evidence and developed through a two-round modified Delphi consensus approach.

RESULTS

The treatment recommendations are summarized as follows: Stage I--complete resection of the entire thymus without neoadjuvant or adjuvant therapy. Stage II--complete resection of the entire thymus with consideration of adjuvant radiation for high-risk tumors. Stage IIIA--surgery either initially or after neoadjuvant therapy, or surgery followed by adjuvant therapy. Stage IIIB--treatment may include a combination of chemotherapy, radiation, and/or surgery, or if technically possible, surgery in combination with chemoradiotherapy (concurrent cisplatin based). For bulky tumors, consideration should be given to sequential chemotherapy followed by radiation. Stage IVA--as per stage III, with surgery only if metastases can be resected. Stage IVB--treatment on an individual case basis (no generic recommendations). Recurrent disease--consider surgery, radiation, and/or chemoradiation. Chemoradiation should be considered in all medically inoperable and technically inoperable patients.

CONCLUSION

Consensus was achieved on these recommendations, which serve to provide practical guidance to the physician treating this rare disease.

Adjuvant radiotherapy for thymic epithelial tumors: a systematic review and meta-analysis

Adjuvant radiotherapy after complete resection of localized, invasive thymic epithelial tumors is considered by many to be the standard of care, despite little supporting literature. We hypothesized that individual studies may lack statistical power to demonstrate a reduction in recurrence with this approach, but meta-analysis of published data may allow for more adequate statistical evaluation. Analysis of data from 592 patients with completely resected stage II or III thymic epithelial tumors, however, revealed no statistically significant reduction in recurrence after adjuvant radiotherapy (odds ratio 1.05; 95% confidence interval: 0.63 to 1.75; p = 0.840). Additionally, the majority of publications suggest that the most common sites of recurrence are the lung, pleura, and diaphragm, even when incompletely resected patients are included.

Postoperative radiotherapy after surgical resection of thymoma: differing roles in localized and regional disease

PURPOSE

To analyze the Surveillance, Epidemiology and End Results (SEER) registry data to determine the impact of postoperative radiotherapy (PORT) for thymoma and thymic carcinoma (T/TC).

METHODS AND MATERIALS

Patients with surgically resected localized (LOC) or regional (REG) malignant T/TC with or without PORT were analyzed for overall survival (OS) and cause-specific survival (CSS) by querying the SEER database from 1973-2005. Patients dying within the first 3 months after surgery were excluded. Kaplan-Meier and multivariate analyses with Cox proportional hazards were performed.

RESULTS

A total of 901 T/TC patients were identified (275 with LOC disease and 626 with REG disease). For all patients with LOC disease, PORT had no benefit and may adversely impact the 5-year CSS rate (91% vs. 98%, p = 0.03). For patients with REG disease, the 5-year OS rate was significantly improved by adding PORT (76% vs. 66% for surgery alone, p = 0.01), but the 5-year CSS rate was no better (91% vs. 86%, p = 0.12). No benefit was noted for PORT in REG disease after extirpative surgery (defined as radical or total thymectomy). On multivariate OS and CSS analysis, stage and age were independently correlated with survival. For multivariate CSS analysis, the outcome of PORT is significantly better for REG disease than for LOC disease (hazard ratio, 0.167; p = 0.001).

CONCLUSIONS

Our results from SEER show that PORT for T/TC had no advantage in patients with LOC disease (Masaoka Stage I), but a possible OS benefit of PORT in patients with REG disease (Masaoka Stage II-III) was found, especially after non-extirpative surgery. The role of PORT in T/TC needs further evaluation.

Thymic epithelial tumours: a population-based study of the incidence, diagnostic procedures and therapy

The population-based incidence, diagnostic procedures, therapy and survival of thymic epithelial tumours were determined using the Netherlands National Pathological Archives and the Netherlands Cancer Registry. Excess mortality compared to the Netherlands standard population was estimated by relative survival analysis. Between 1994 and 2003, 537 thymic epithelial tumours were diagnosed. The incidence of all thymic epithelial tumours was 3.2/1,000,000. Diagnosis was obtained by primary resection in 56% of cases. Survival data were available for 232 cases. Not only thymic carcinomas (type C) but also thymomas (types B1-B3) were associated with excess mortality. Cases that underwent resection (78%) had a better survival than non-operated cases (median survival >10 years versus 1.1 years, p<0.001). Amongst the surgically treated cases (n=180), the completeness of resection did not predict survival (p=0.53). Thymic epithelial tumours are rare. Excess mortality was observed in the majority of tumours. Surgery offers the best perspectives, even if the resection is incomplete.

Clinical value of the WHO classification system of thymoma

Since the World Health Organization (WHO) histologic classification system for thymoma was introduced in 1999, several centers have published results using this system. This review of the published experience with the WHO system examines whether the classification is reproducible, whether the WHO system defines clinically distinct patient groups, assesses the independent prognostic value of the WHO type by multivariate analysis, and discusses the impact of the WHO system on clinical management decisions.

Management of thymomas

Thymoma is a rare neoplasm usually with an indolent growth pattern, however, local invasion and/or metastases may occur. The association with several paraneoplastic syndromes, especially myasthenia gravis, is noteworthy. Surgery has been the standard of care for early stage disease with high cure rates anticipated. The most important prognostic factors after resection are Masaoka stage, World Health Organization (WHO) histology, complete resection status and size. Multimodality therapy can result in long-term disease-free survival for patients presenting with locally advanced disease. Thymomas are sensitive to both chemotherapy and radiation therapy and are utilized with good effects in unresectable patients.

The Thymus: A Comprehensive Review

Since first being described as such by Galen of Pergamum (130-200 ad), the thymus has remained an "organ of mystery" throughout the 2000-year history of medicine. The thymus reaches its maximum weight in puberty and subsequently undergoes involution, and thus is hardly an eye-catching structure on imaging studies performed in healthy adults. However, once there has been involvement of the thymus by a disease process, the gland demonstrates a variety of clinical and radiologic manifestations that require comprehensive understanding of each entity. Furthermore, it is important for radiologists to be familiar with the current World Health Organization histologic classification scheme for thymic epithelial tumors and to understand its clinical-pathologic, radiologic, and prognostic features.

Long-term disease-free survival of patients with radically resected thymomas: relevance of cell-cycle protein expression

BACKGROUND

Despite radical surgical resection, thymomas often recur. The objective of the current retrospective study was to investigate the prognostic relevance of the expression of cell-cycle proteins in these neoplasms to formulate a possible therapeutic surveillance strategy for the prevention of recurrence.

METHODS

The authors retrospectively reviewed the main clinicopathologic factors, including the World Health Organization (WHO) classification, of patients with thymoma who had undergone radical surgical resection. Specimens were studied using immunohistochemistry and the expression of cell-cycle proteins (i.e., p21, p27, and p53) was assessed. Univariate and multivariate analysis of predicting survival prognostic factors were performed.

RESULTS

The authors analyzed 88 patients with thymoma who underwent radical surgical resection at the study institution. According to the Masaoka staging system, 41 patients had Stage I disease, 31 patients had Stage II disease, and 16 patients had Stage III disease. There were 24 tumor recurrences (27.3%), 4 of which were local, 16 of which were distant intrathoracic, and 4 of which were extrathoracic. The second radical resection provided a disease-free survival rate that was similar to the first. Only Masaoka stage (P = 0.001), WHO classification (P=0.001), high expression of p53 (P=0.03), and low expression of p21 (P=0.02) and p27 (P=0.001) were found to be correlated with a reduced disease-free survival. Low p27 expression was found to be the most significant predictive factor of a short disease-free survival (P=0.001), especially when associated with low p21 expression and high p53 expression (P=0.0001).

CONCLUSIONS

Long-term disease-free survival in thymoma patients treated with radical surgical resection was found to be correlated with Masaoka stage, WHO classification, and expression of cell-cycle proteins, with the latter found to be the most significant predictive factor. Functional cooperation between cell-cycle proteins might constitute another level of regulation in tumor growth. More careful surveillance should be adopted whenever there is negative cell-cycle protein expression.

Proposal of a Novel System for the Staging of Thymic Epithelial Tumors

BACKGROUND

We designed and assessed a new TNM staging system (herein called the INT [Istituto Nazionale Tumori] system) for thymic epithelial tumors in order to overcome the perceived drawbacks of Masaoka's system, which represents the current standard.

METHODS

In all, 123 cases were evaluated. The histologic types according to the World Health Organization (WHO) classification were as follows: subtype A: 5 cases; AB: 40; B1: 16; B2: 29; B3: 16; and C: 17 cases. There were 45 Masaoka's stage I, 33 stage II, 26 stage III, and 19 stage IV cases. A total of 11 INT definitions were grouped into three stages: locally restricted disease (75 cases), which included Masaoka's stage I and selected stage II cases (no pleural invasion); locally advanced disease (37 cases), which included Masaoka's stage III cases plus those staged II owing to pleural invasion and those staged IV owing to intrathoracic nodal or limited pleuropericardial involvement; and systemic disease (11 cases), which included the remaining Masaoka's stage IV cases.

RESULTS

Completeness of resection, WHO types, and both staging systems were significant prognostic factors (p < 0.0001) on univariate analysis. The 95-month progression-free survival rates according to Masaoka's system were stage I: 100%; II: 93.6%; III: 46.3%; and IV: 23.2%. The INT system corresponding figures were as follows: locally restricted disease: 98.6%; locally advanced disease: 46.9%; and systemic disease: 11.7%. The INT system was the prognostic factor with the greatest impact (p = 0.0218) on multivariate analysis (Masaoka's system: p = 0.2012; completeness of resection: p = 0.6855; histology: p = 0.9386).

CONCLUSIONS

The INT system allows finer disease descriptions than Masaoka's system, resulting in a stage grouping with higher prognostic distinctiveness.

Analysis of cell cycle regulator proteins in encapsulated thymomas

PURPOSE

Although survival of encapsulated thymomas is usually good, some patients present a higher incidence rate of recurrence and a shorter long-term survival. Abnormalities in the components of cell cycle checkpoints are extremely common among virtually all neoplasms. In this study, three components of the cell cycle machinery (i.e., p21, p27 and p53) were examined in a series of well-characterized encapsulated thymoma specimens to analyze coregulation and influence on recurrence and survival.

EXPERIMENTAL DESIGN

Sixty-eight consecutive patients with thymoma were operated in our center from 1987 to 2000. Expression of p53, p21, and p27 was studied in specimens from 25 encapsulated thymomas using immunohistochemistry. Generic factors and gene expression influencing the probability of recurrence were studied. Positive expression was dichotomized defining positive when present in more than 5% of tumor cells. Mean follow up was 85.9 months; clinical data about recurrence were recorded.

RESULTS

Univariate analysis suggests that positive p53 (P < 0.05), negative p21 (P = 0.01), and especially negative p27 expressions (P = 0.001) significantly correlate with poor prognosis for disease-free survival. Multivariate Cox regression analysis suggests that negative p27 immunohistology is the only significant variable for poor prognosis (P = 0.03; odds ratio, 0.08; 95% confidence interval, 0.01-0.88).

CONCLUSIONS

These results show that loss of control of cell cycle checkpoints is a common occurrence in thymomas and support the idea that functional cooperation between different cell cycle inhibitor proteins constitutes another level of regulation in cell growth control and tumor suppression.

World Health Organization histologic classification: An independent prognostic factor in resected thymomas

The histologic classification of thymoma remained controversial since 1999, when the World Health Organization (WHO) Consensus Committee published a histologic typing system for tumours of thymus. Clinical features, postoperative relapsing rates, and survival of patients with thymoma were evaluated with reference to the WHO histologic classification, based on a series of 178 patients, submitted to surgery between 1988 and 2000. There were 21 type A, 49 type AB, 45 type B1, 50 type B2 and 13 type B3 tumours. The invasiveness of tumours was 23.8%, 51%, 73.3%, 82% and 100% for types A, AB, B1, B2 and B3 tumours, respectively. The frequency of invasion of the great vessels increased according to the tumour type in the order A (0%), AB (4%), B1 (6.6%), B2 (22%), and B3 (23%). The 10-year disease-free survival was 95%, 90%, 85%, 71% and 40% for types A, AB, B1, B2 and B3, respectively. According to the Masaoka staging system, the disease-free survival rates were 94%, 88% and 66% for stages I, II and III, respectively, at 10 years. No stage IVA thymomas reached 10 years follow-up. Overall survival at 10 years were 88% and 25% when complete and incomplete resection were considered. By multivariate analysis, Masaoka staging system, WHO histologic classification and complete resection were significant independent prognostic factors, whereas age- and sex-associated myasthenia gravis were not. The present study demonstrated the World Health Organization histologic classification a good prognostic factor, such as completeness of surgical resection and Masaoka staging system.

Thymoma in a child: case report and review of the literature

Thymic lesions comprise approximately 2-3% of all pediatric mediastinal tumors and include thymic cysts, hyperplasia, carcinoma, and thymomas. Thymomas, which represent less than 1% of all mediastinal tumors, are rare mediastinal tumors in the pediatric population. Fewer than 30 cases in children have been described in the literature. These tumors are typically aggressive, with poor outcomes. We report a thymoma in a 14-year-old girl and review the available literature on thymomas and their treatment.

Adjuvant Radiation of Stage III Thymoma: Is It Necessary?

BACKGROUND

The criteria for administration of adjuvant radiation therapy after thymoma resection remains controversial, and it is unclear whether patients with Masaoka stage III thymoma benefit from adjuvant radiation. The goal of this report was to determine whether or not this group benefits from radiation therapy in disease-specific survival and disease-free survival.

METHODS

Case records of the Massachusetts General Hospital were retrospectively reviewed from 1972 to 2004. One hundred and seventy-nine patients underwent resection for thymoma, of which 45 had stage III disease.

RESULTS

Forty-five stage III patients underwent resection and in 36 it was complete. Thirty-eight stage III patients received radiation therapy. Baseline prognostic factors between radiated and nonradiated groups were similar. The addition of adjuvant radiotherapy did not alter local or distant recurrence rates in patients with stage III thymoma. Disease-specific survival at 10 years in stage III patients who did not receive radiation was 75% (95% confidence interval, 32% to 100%) and in patients who did receive radiation therapy it was 79% (95% confidence interval, 64% to 94%) (p = 0.21). The most common site of relapse was the pleura.

CONCLUSIONS

Most patients who have stage III thymoma undergo complete resection. Some patients enjoy prolonged disease-free survival without adjuvant radiation after resection of stage III thymoma. Radiation does not seem to prevent pleural recurrences when given after resection of stage III thymomas. The use of routine adjuvant radiation after a complete resection of stage III thymoma needs to be re-addressed. There may be a role for the use of chemotherapy to reduce pleural recurrences.