Reoperation for thymoma: report of 23 cases

[Mediastinal Tumors]

If mediastinal tumours cause symptoms these are related to their anatomical localization or a paraneoplastic syndrome. The differential diagnosis is based on the clinical situation with finding the lesion, and, furthermore, taking into account the age and sex of the patient, and the mediastinal compartment where the lesion is located. Cross-sectional radiographic diagnostic is essential for defining the therapeutic strategy. The anterior mediastinum is dominated by thymic tumours, mediastinal lymphomas, germ cell tumours and ectopic mediastinal poiters. The middle mediastinal compartment is the most frequent place of mediastinal cystic tumours, whereas the posterior mediastinum is the domain of neurogenic tumours. For selected cases a tissue biopsy is required. Surgery is the mainstay for most mediastinal tumours. Median sternotomy is the most frequent conventional surgical technique while minimally invasive surgery with thoracoscopic and above all robot assisted operation techniques are increasingly frequent. Combined chemotherapy and modern radiotherapy are essential components of the comprehensive treatment for mediastinal tumours.

[Comparative analysis of video-assisted thoracic surgery versus open resection for early-stage thymoma]

BACKGROUND

Video-assisted thoracic surgery (VATS) has significantly developed over the last decade. However, a VATS approach for thymoma remains controversial. The aim of this study was to evaluate the feasibility of VATS thymectomy for the treatment of early-stage thymoma and to compare the outcomes with open resection.

METHODS

A comparative study of 59 patients who underwent surgical resection for early stage thymoma (VATS: 44 and open resection: 15) between 1993 and 2011 was performed. Data of patient characteristics, morbidity, mortality, length of hospital stay, the relationship between miasthenia gravis-thymoma, recurrence, and survival were collected for statistical analysis.

RESULTS

Thymomas were classified according to Masaoka staging system: 38 in stage I (VATS group: 29 and open group: 9) and 21 in stage II (VATS group: 15 and open group: 6). The mean tumor size in the open group was 7.6cm (13-4cm) and in the VATS group 6.9cm (12-2.5cm). The average length of stay was shorter in the VATS group than in the open group (P<.001). No significant differences were found in the estimated recurrence-free and overall 5-year survival rates (96% vs. 100%) between the 2 groups.

CONCLUSIONS

VATS thymectomy for early-stage thymoma is technically feasible and is associated with a shorter hospital stay. The 5-year oncologic outcomes were similar in the open and VATS groups.

Management and outcomes of relapse after treatment for thymoma and thymic carcinoma

BACKGROUND

Although surgery is the mainstay of treatment for thymic tumors, recurrence is common despite resection. The optimal approach to the management of disease relapse after treatment for thymic tumors remains unclear.

METHODS

This study is a retrospective analysis of a single-institution experience assessing treatment patterns and outcomes in patients with recurrence or disease progression after surgical treatment for thymic tumors. Data included demographics, stage, treatment, pathologic findings, and postoperative outcomes.

RESULTS

From 1995 to 2006, 120 patients had initial resection of a thymic tumor at our institution, of which 112 had recurrence data available. Twenty-five patients developed recurrence or progression of disease after their initial resection (10 thymic carcinoma, 15 thymoma). Median follow-up was 51.4 months. Higher Masaoka stages predominated (I: 0; II: 4; III: 8; IV: 13). Eleven patients (44%) underwent surgery for their relapse with curative intent, while 14 (56%) were managed nonsurgically. Surgery was considered when disease was intrathoracic, unilateral, and technically resectable. The 11 patients receiving surgery had a total of 16 reoperations (range 1 to 4). An R0 re-resection was obtained in half of cases (8 of 16, 50%) but the majority of operative patients (9 of 11, 82%) recurred again. The 5-year overall survival of the 25 patients with recurrent or persistent disease was 58% (median survival = 82 months). Kaplan-Meier curves demonstrate a trend (p = 0.08) toward improved overall survival in patients treated with surgery versus those treated nonoperatively (median survival = 156 months versus 50 months). Patients with thymoma demonstrated a trend (p = 0.12) toward improved survival for over thymic carcinoma (median survival = 90 months versus 35 months).

CONCLUSIONS

Treatment of patients with recurrent or progressive thymic tumors is associated with long-term survival. Despite the historical enthusiasm for re-resection, the majority of patients will recur again, therefore reoperation should be considered only in selected patients.

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.

Observation and extirpation of a giant-size type-B2 thymoma IIb with its histological, macroscopic, and computer tomogram correlate, and literature review

This report describes the interdisciplinary approach and solving algorithm of a DIN 9001:2000 certified tumor board in managing a giant-size type-B2 thymoma IIb in an elderly patient. The process of managing the thymoma with specialists of surgery, internal medicine, radiology, and pathology until finally extirpation and continuous follow-up is described. Respective computerized tomography scans, histology, macro-pathology, and operative pictures of the case are provided as well as an upto-date literature review.

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.

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.

Outcome of surgical treatment for recurrent thymic epithelial tumors with reference to world health organization histologic classification system

BACKGROUND AND OBJECTIVES

The aim of this study was to clarify the significance of surgical treatment for recurrent thymic epithelial tumors with reference to the World Health Organization (WHO) histological classification system.

PATIENTS

Among 67 patients with tumor recurrence, 22 underwent a re-resection. There were 1 patient with a type AB tumor, 5 with type B1 tumors, 10 with type B2 tumors, 5 with type B3 tumors, and 1 with a carcinoma.

RESULTS

The 10-year survival rate following the initial resection was 70% in patients who underwent a re-resection and 35% in those who did not. The average intervals from the initial resection to re-resection were 10.3, 7.8, 6.0, 2.4, and 2.6 years for patients with type AB, B1, B2, B3 tumors, and carcinoma, respectively. The patient with a type AB tumor was alive at 2.4 years after re-resection, 12.7 years after the initial resection. The 5-year survival rates following re-resection in the patients with type B1, B2, and B3 tumors were 100, 56, and 60, respectively. The patient with a carcinoma died as a result of the tumor 2 years after re-resection.

CONCLUSION

WHO histological classification indicates the outcome of surgical treatment for recurrent thymic epithelial tumors.

Tumeurs épithéliales thymiques

Thymomas and thymic carcinomas are rare and slow-growing tumors, which develop within the anterior mediastinum. Thymomas are often associated with autoimmune disorders and most particularly myasthenia gravis. The treatment of choice remains a complete surgical resection. Postoperative radiotherapy is often combined in case of invasive thymoma invading into adjacent organs. Postoperative radiotherapy in stage II with invasion into capsule has been more controversial lately. In inoperable locally advanced, or metastatic thymic tumors, neoadjuvant cisplatin-based followed by surgery and radiotherapy has given interesting results in the past years.

Surgical treatment of thymic tumors

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, makes thymoma an interesting biologic tumor model. Surgery has been the standard of care for early stage disease with high cure rates anticipated. Multimodality therapy can result in long-term disease-free survival for patients presenting with locally advanced disease.

Treatment of recurrent thymic tumors

Surgery is the cornerstone of therapy for recurrent thymic tumors. The pattern of recurrence is, however, less defined. Between 1966 and 1988, we operated on 83 patients with thymoma, 11 of whom underwent surgery for recurrence (group I). In 1989, we initiated a prospective multimodality protocol and have enrolled 128 patients with 9 (7%) recurrences since (group II). In group I, 1 patient was originally at stage I, 2 were at stage II, 5 at stage III, and 3 at stage IV. The patients underwent 1 (#10) or 2 (#1) reoperations and 5 showed histological progression of malignancy. One patient died postoperatively, 6 died of disease, and 3 are alive and disease free 18 to 22 years after the first operation. In group 2, no patient was originally at stage I, 1 was at stage II, 4 were at stage III, and 4 at stage IV. Reoperation (5 patients) was followed by chemotherapy and 2 showed histological progression of disease. One patient died after 2 years, and 4 patients are alive after 6 to 11 years. All recurrent tumors were thymomas with cortical differentiation. Early onset of recurrence was a negative prognostic factor. Thymomas can recur also at early stages. A multimodality approach is indicated also for early stage lesions based on histology.

Application of Robotic-Assisted Techniques to the Surgical Evaluation and Treatment of the Anterior Mediastinum

BACKGROUND

We report our initial experience with the application of robotic-assisted technologies to the treatment of diseases of the anterior mediastinum.

METHODS

Between October 2001 and December 2003, 18 consecutive patients with anterior mediastinal masses were referred for diagnosis and treatment. Fifteen patients underwent robotic-assisted surgery with the da Vinci robotic system. A single surgical team performed all operations. Resection was accomplished by either median sternotomy or robotic-assisted techniques.

RESULTS

Fourteen patients underwent successful robotic-assisted thymectomy. One patient underwent robotic-assisted biopsy of a mass that was later determined to be a poorly differentiated carcinoma, 3 patients underwent complete thymectomy by median sternotomy for biopsy-proven extracapsular thymoma, 7 patients had thymoma, and 3 had myasthenia gravis. There were 2 patients each with benign thymic cysts and thymic hyperplasia. Primary thymic carcinoid, thymolipoma, papillary thyroid cancer, and poorly differentiated carcinoma were present in 1 patient each. No conversions, intraoperative complications, or deaths occurred in the 15 patients who underwent robotic-assisted resection. The mean operative time was 96 minutes (range 62 to 132 minutes). The mean robotic time was 48 minutes (range 22 to 76). The median hospital stay was 2 days. All patients are doing well, with a median follow-up of 1 year.

CONCLUSIONS

Robotic-assisted surgery of the anterior mediastinum, and particularly thymectomy, can be performed safely and efficiently. The increased visualization and instrument dexterity afforded by this technology provides an optimal minimally invasive approach to the anterior mediastinum. From this experience we have formulated a comprehensive treatment algorithm for the surgical evaluation and treatment of patients with anterior mediastinal diseases.

Thymic tumors

Thymic tumors include thymic carcinoma, which exhibit aggressive behavior, and thymomas, which manifest a more indolent course. Complete resection is the mainstay of treatment, and there appears to be little benefit to partial resection. Postoperative radiotherapy may be useful in incompletely resected patients. Preoperative chemotherapy appears to increase the rate of complete resection and survival of patients with a stage III or IVa thymoma and should strongly be considered in such cases.

Recurrence of thymoma: clinicopathological features, re-operation, and outcome

BACKGROUND

Even after complete resection, recurrence of thymoma is not infrequently observed, and treatment of recurrent thymoma remains controversial.

STUDY DESIGN

One hundred and twenty-six patients underwent surgically complete resection for thymoma, and 24 of them had a recurrence. Surgical treatment of recurrent thymoma was attempted in 15 patients for a total of 18 times. In the present study, the relevance of clinicopathological features and the re-operation on the survival rate after the recurrence were determined.

RESULTS

The most frequent recurrent type was pleural dissemination (92%), with local recurrence observed in 5%. Overall 5- and 10-year survivals after recurrence were 37 and 16%, respectively. Disease-free interval after initial operation and complication of myasthenia gravis had no significant effect on postrecurrent survival. The use of postoperative mediastinal irradiation had no effect on reducing the recurrence rate or improving survival after recurrence. Two of 15 patients who underwent re-operation died of major complications after It. pleuropneumonectomy for severe pleural dissemination. In the present study, the re-operation was not significantly effective for prolongation of postrecurrence survival.

CONCLUSION

Our study showed that re-operation should not be attempted for all patients with recurrent thymoma. Because effect of subtotal resection for severe pleural recurrence is disappointing, total resection for minimal pleural dissemination or small local recurrence will be undertaken to improve postrecurrent survival. Careful follow-up for > 10 years will increase the chance of the total resection of the recurrent thymoma.

Thymoma: update for the new millennium

Thymomas are relatively common tumors of the anterior superior mediastinum. They are usually relatively slowly growing tumors and their prognosis depends on the macroscopic and microscopic invasion of surrounding tissues. Surgery is the mainstay treatment of thymomas, and complete resection represents one of the most important prognostic factors in this disease. Other important prognostic indicators include the tumor stage and size and the presence of symptoms. Postoperative radiotherapy is indicated in tumors with invasion of surrounding tissues, even if resection was radical, since it improves local control and survival. Cytotoxic chemotherapy has been employed in several relatively small phase II studies and in advanced disease has been demonstrated to produce a 50%-80% objective response rate. Neoadjuvant cytotoxic chemotherapy and/or external beam radiotherapy has been used with some success in patients with tumors which are not readily resectable. Novel antiproliferative systemic agents, with both cytotoxic and cytostatic mechanisms of action, are being tested in ongoing prospective clinical trials.

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.

Thymoma. Analysis of prognostic factors

OBJECTIVE

We evaluated the prognostic factors for thymoma that remain controversial.

METHODS

We studied 72 consecutive patients treated for thymoma during the period between 1966 and 1997. Recurrence-free interval rates and overall survival rates calculated by the Kaplan-Meier method were compared using log-rank test by the Masaoka stage, extent of surgical resection, histology, or associated disease(s). Multivariate analysis was performed using Cox's proportional hazards model.

RESULTS

Thirty-two thymomas were at Masaoka stage I, 9 at stage II, 15 at stage III, and 16 were at stage IV. There were 56 complete resections, 7 incomplete resections (2 at stage III and 5 at stage IV), and 9 biopsies (1 at stage III and 8 at stage IV). Forty-one thymomas were cortical, 16 medullary, and 15 were mixed form. Association of myasthenia gravis was found in 20 patients, and pure red cell aplasia in 7. After an average follow-up period of 103 months, the recurrence-free 5-, 10-, 15-year interval rate was 89%, 80%, 80%, respectively, and overall 5-, 10-, 15-year survival rate was 86%, 71%, 59%, respectively. Factors influencing the recurrence-free interval and overall survival included the Masaoka stage, extent of surgical resection, and association with pure red cell aplasia. Multivariate analysis revealed stage IV tumor and association with pure red cell aplasia as risk factors for recurrence. Pure red cell aplasia indicated poor prognosis for overall survival.

CONCLUSIONS

Masaoka stage, extent of surgical resection, and association with pure red cell aplasia were prognostic factors for thymoma. Multidisciplinary treatment for stage IV tumors and better control of pure red cell aplasia, if associated, should be investigated.

Current status of the diagnosis and treatment of thymoma

Although thymomas are rare neoplasms, they are the most common tumor of the anterior mediastinum in adults. Preferred therapy for these neoplasms is complete surgical resection. If a thymoma cannot be completely resected, postoperative radiotherapy may produce satisfactory results in controlling the tumor. Significant 5- and 10-year survival rates have been recorded for patients with advanced thymomas who have been treated by radiation therapy alone. Chemotherapy may be used in patients with unresectable thymomas as well, but the results are less promising than with radiotherapy. Combinations of radiotherapy and chemotherapy used on patients with unresectable thymomas have produced encouraging results. Surveillance of patients with thymoma should be prolonged because late recurrence (more than 5 years after initial therapy) can be expected in a significant minority of patients. Aggressive therapy of late recurrence, including resection of new tumor masses and pleural metastases, has yielded successive disease-free intervals that validate persistent treatment.

Tiny thymic carcinoma completely surrounded by thymic tissue. The possibility of de novo carcinoma

We report a case of a 61-year-old man with a tiny thymic carcinoma completely surrounded by thymic tissue. First, a thoracoscopic resection of about two-thirds of the right inferior part of the thymus containing the tumor was performed to obtain the histological diagnosis. Frozen-section diagnosis at operation revealed a thymic carcinoma. Therefore we performed a median sternotomy and resected the remnant of the thymus. A tiny thymic carcinoma completely surrounded by thymic tissue is extremely rare. In this case, as the tumor was tiny and there was a homogeneous mass without a thymoma-like component, we concluded that this tumor was de novo.

Primary chemotherapy with adriamycin, cisplatin, vincristine and cyclophosphamide in locally advanced thymomas: a single institution experience

From 1990 to 1997, 16 consecutive patients with stage III and IVa invasive thymoma were treated in a single institution with primary chemotherapy consisting in adriamycin (40 mg m(-2)), cisplatin (50 mg m(-2)) administered intravenously on day 1, vincristine (0.6 mg m(-2)) on day 2 and cyclophosphamide (700 mg m(-2)) on day 4 (ADOC). The courses were repeated every 3 weeks. The aim was to evaluate the impact of this cytotoxic regimen with respect to response rate, per cent of patients radically resected, time to progression and overall survival. Two complete responses (one clinical and one pathological) and 11 partial responses were observed (overall response rate 81.2%); two patients had stable disease and one progressed. Toxicity was mild as only two patients developed grade III/IV neutropenia and one patient grade III nausea/vomiting. Nine patients were radically resected (five out of ten with stage III, and four out of six with stage IVa). Median time to progression and overall survival was 33.2 and 47.5 months respectively. Three patients were alive and disease free after more than 5 years. The ADOC scheme is highly active and manageable in the treatment of locally advanced thymoma. As a preoperative approach it should be offered to patients not amenable to surgery or to those surgically resectable but with a great deal of morbidity.

Thymoma: state of the art

Thymoma is the most common tumor of the anterior mediastinum. This tumor is associated with unique paraneoplastic syndromes, such as myasthenia gravis, hypogammaglobulinemia, and pure red cell aplasia. The rarity of this tumor, however, has somewhat obscured the optimal treatment for this disease. For the majority of patients who present with localized tumor, surgical extirpation remains the standard of choice. Adjuvant radiotherapy seems to improve local control and survival. In more advanced disease, systemic therapy has been demonstrated to produce a 50% to 80% objective response rate. These observations have led to the development of multimodality therapy for the treatment of patients with advanced thymoma. In this article, we will review the current perspectives on the management of early stage and advanced thymoma.

[Recurring invasive thymoma of the diaphragm]

Diaphragmatic recurrence of a thymoma is rare. We report the case of a 70-year-old woman who underwent transternal thymectomy and adjuvant radiation therapy, and who was admitted four years later with recurrence of the thymoma in the left hemidiaphragm with infiltration of the inferior ipsilateral pulmonary lobe. The thymoma was excised along with the left hemidiaphragm, chest wall and three ribs and an atypical segmentectomy of the left lower lobe was performed. The hemidiaphragm was reconstructed and the chest wall was repaired with synthetic mesh. Surgery was complemented with radiotherapy.

Thymectomy for myasthenia gravis

The pathophysiological role of the thymus in myasthenia gravis, and the mechanism of therapeutic effect of thymectomy, are incompletely understood. Nevertheless, thymectomy is a valuable treatment modality in selected patients with generalised myasthenia gravis. There are several types of thymectomy operation, but no one operative approach is clearly superior to the others. Total removal of the thymus gland is essential. Additional excision of associated mediastinal and cervical tissue, that may harbor ectopic thymic rests, is a controversial surgical issue. Surgeons that advocate thymectomy through small, cosmetically favourable, incisions usually believe that simple removal of the thymus gland is an adequate operation. Surgeons that emphasise the importance of removing extrathymic tissue, in addition to the thymus gland, usually favour greater operative exposure through a median sternotomy. To minimise operative morbidity, surgery for myasthenia gravis requires a multidisciplinary (neurology, surgery, anaesthesia) approach to peri-operative care.

Results of re-resection for recurrent thymomas

BACKGROUND

The treatment of recurrent thymomas remains controversial.

PATIENTS

The place for re-resection was retrospectively studied in 28 consecutive patients operated on during the last 40 years. The initial Masaoka staging of the thymoma was stage I, 4; stage II, 8; stage III, 11; and stage IVa, 3. Postoperatively, 14 have had radiation therapy, 1 chemotherapy, and 13 no adjuvant treatment. Seven patients had development of recurrences, 15 had pleuropulmonary metastases, 5 had both, and 1 had thoracotomy scar recurrence. Nineteen patients had a complete resection and 9 an incomplete one.

RESULTS

Most local recurrences appeared after resection of stage I or II thymomas. On the other hand, in patients with stage III or IV thymomas pleural or pulmonary metastases mainly developed. No local recurrence occurred in patients who initially received postoperative radiation therapy. Five-year and 10-year survival rates were 51% and 43%, respectively, for the overall population. Among the 19 patients with complete resection, only 3 patients had a subsequent recurrence; 1 of them could be reoperated on and is still alive and free of disease.

CONCLUSIONS

Thymoma recurrences often appear as a locoregional rather than a hematogenous spread. Reresection can be recommended in selected patients.

Controversies in the management of malignant thymoma

The management of most thymomas is relatively straightforward: surgical resection remains the primary mode of therapy. However, the literature contains many contradictory points of view regarding histology and pathology, staging and its usefulness, the need for adjuvant therapy, and recently, the place of video-assisted surgery in the treatment of this tumor. This article is not a comprehensive guide to management but rather explores several of these controversial areas. Conclusions include the following: invasiveness remains the single most consistent factor in predicting outcome; surgery is the treatment of choice for thymoma whenever a complete resection can be accomplished; and incomplete resection may have some advantage over biopsy alone. The preponderance of evidence indicates that all thymomas except completely encapsulated stage I tumors should be treated with postoperative adjuvant radiation therapy in the hope of reducing the incidence of local relapse. Myasthenia can no longer be considered an adverse prognostic factor in thymoma; it may even confer a survival advantage, but this may be due to the preponderance of early-stage tumors discovered incidentally in myasthenic patients. Other associated autoimmune diseases confer a survival disadvantage. Demonstrating the equivalence of minimally invasive thoracoscopic approaches to standard thymectomy will take many years of investigation. Some promising reports on response to chemotherapy have led to the development of a phase II intergroup study to assess the value of chemotherapy in advanced 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.

Recurrence of thymoma: analysis of clinicopathologic features, treatment, and outcome

OBJECTIVE AND METHODS

This study reports clinicopathologic features, treatment, and outcome of 30 recurrent thymomas out of 266 totally resected thymomas.

RESULTS

The mean disease-free interval to recurrence was 86 months. Recurrence occurred less frequently and after a longer disease-free interval after resection of encapsulated versus invasive thymomas. The presence of associated myasthenia gravis did not affect recurrence proportion, disease-free interval, or survival after recurrence. A local recurrence occurred in 11 patients, 17 patients had a distant recurrence, and the extent of the recurrence could not be determined in 2 cases. Surgical treatment of the recurrent tumor was attempted in 16 cases, and a total resection was possible in 10 cases; exclusive radiotherapy was done in 11 cases. Overall 5- and 10-year survivals were 48% and 24%, respectively. In a univariate analysis, survival was significantly better in the presence of a local recurrence and in case of a total resection of the recurrent tumor. The use of adjuvant therapy after the resection of the initial thymoma had no effect on reducing the incidence of recurrence, in prolonging the disease-free interval, or in improving survival after the development of the recurrence. In a multivariate survival analysis, significant prognostic factors were the presence of a local recurrence and total resection of the recurrent tumor.

CONCLUSIONS

Surgical resection is recommended in patients with recurrent thymoma. Local recurrence and total resection of the recurrent tumor are associated with excellent prognosis. A poor prognosis may be anticipated in the presence of distant recurrence and when radical surgical treatment is not done.

Results of video-assisted thymectomy in patients with myasthenia gravis

OBJECTIVE

The efficacy of video-assisted thoracic surgery for thymectomy with myasthenia gravis has not been examined.

METHODS

Thirty-three consecutive patients underwent total thymectomy by video-assisted techniques between 1992 and 1995. There were 13 male and 20 female patients with a mean age of 38.42 +/- 16.88 years (range 9 to 84 years). The procedures were performed by either a right (n = 11) or left (n = 22) thoracoscopic approach and all anterior mediastinal tissue was removed.

RESULTS

There was no perioperative mortality or long-term morbidity. One patient required conversion of the video-assisted technique to a lateral thoracotomy. All patients except one were extubated immediately. The mean hospital stay was 4.12 +/- 6.07 days (range 1 to 37 days) with a median of 3 days. Mean follow-up is 23.39 +/- 11.72 months (range 4 to 47 months). Clinical improvement was seen in 87.9% (29/33): one of two patients (50%) in stage I, 17 of 19 (89.4%) in stage IIA, eight of nine (88.8%) in stage IIB, and three of three (100%) in stage III. Metaanalysis of these results compared with results in nine published series in which other techniques were used showed no difference in clinical improvement after thymectomy between series.

CONCLUSION

We conclude that video-assisted thymectomy is as effective as the traditional open surgical approaches for performance of thymectomy in the management of patients with myasthenia gravis. In addition, the improved cosmesis of the video-assisted approach ideally will lead to earlier thymectomy in patients with myasthenia gravis.

Prognostic factors and long-term results after thymoma resection: a series of 307 patients

Three hundred seven cases of patients who underwent operation for thymoma (196 of whom had myasthenia gravis) were analyzed to assess the prognostic values of Masaoka clinical staging, completeness of resection, histologic classification, history of myasthenia gravis, and postoperative radiotherapy. According to the Masaoka staging system, 135 thymomas were stage I, 70 were stage II, 83 were stage III, and 19 were stage IV. According to the Verley and Hollmann histologic classification system, 67 thymomas were type 1, 77 were type 2, 139 were type 3, and 24 were type 4. Two hundred sixty patients underwent complete resection, 30 underwent incomplete resection, and 17 underwent biopsy. Postoperative radiotherapy was performed mainly in cases of invasive or metastatic thymoma. Mean follow-up was 8 years; eight patients were unavailable for follow-up. The overall 10- and 15-year survivals were 67% and 57%, respectively. In univariate analysis, three prognostic factors were established: completeness of resection, Masaoka clinical staging, and histologic classification. Furthermore, among patients with stage III thymomas, survival was significantly higher for patients with complete resection than for patients with incomplete resection (p < 0.001). Completeness of resection should therefore be taken into account in clinical-pathologic staging. We did not find any significant difference with respect to disease-free survival between patients who had postoperative radiotherapy and those who did not. In multivariate analysis, the sole significant prognostic factor was completeness of resection. On the basis of these findings, a new clinical-pathologic staging system is proposed.

Thymoma: a multivariate analysis of factors predicting survival

BACKGROUND

Despite complete surgical excision, malignant thymomas often recur with resultant death. We reviewed our series to determine which factors independently predict survival after surgical resection.

METHODS

A retrospective analysis of patients operated on for thymoma between 1949 and 1993 at Memorial Sloan-Kettering Cancer Center was performed. Clinical data were collected from chart review. Only patients with a pathology report confirming the diagnosis of thymoma were included in this analysis. Kaplan-Meier survival curves were generated and comparisons of survival analyzed by log rank test. Multivariate analysis was performed by the Cox proportional hazard model.

RESULTS

One hundred eighteen patients with thymoma underwent operation. There were 86 complete resections (73%), 18 partial resections (15%), and 14 biopsies (12%). By Masaoka staging, 25 patients were stage I (21%), 41 stage II (35%), 43 stage III (36%), and 9 stage IVa (8%). Overall survival was 77% at 5 years and 55% at 10 years. Tumor recurred in 25 (29%) of 86 completely resected thymomas. Stage of disease (p = 0.03) was the only independent prognostic factor affecting recurrence. By multivariate analysis, stage (p = 0.003), tumor size (p = 0.0001), histology (p = 0.004), and extent of surgical resection (p = 0.0006) were independent predictors of long-term survival.

CONCLUSIONS

Patients with stage I disease require no further therapy after complete surgical resection. Neoadjuvant therapy should be considered for patients with large tumors and invasive disease.

Radiotherapy and chemotherapy for invasive thymomas: a multicentric retrospective review of 90 cases. The FNCLCC trialists. Fédération Nationale des Centres de Lutte Contre le Cancer

PURPOSE

Thymoma is a rare disease. The treatment of patients with invasive thymoma remains controversial. The prognosis of such patients is poor, even with the use of postoperative radiation therapy and chemotherapy. We retrospectively reviewed the outcome and prognostic factors in a series of 90 patients presenting with an invasive thymoma treated by partial resection or biopsy and radiation therapy.

METHODS AND MATERIALS

From 1979-1990, 163 patients with the diagnosis of lymphoepithelial thymoma were treated in 10 French cancer centers. Patients were staged using the postoperative "GETT" classification derived from that of Masaoka. Ninety patients who presented with an invasive thymoma, 58 Stage III (21 IIIA: partial resection and 37 IIIB: biopsy) and 32 Stage IVA (intrathoracic thymoma spread), are the subject of this report. Treatment combined surgery and radiation therapy (+/- chemotherapy), with curative intent. Surgery consisted of partial resection in 31 patients (21 Stage III), and biopsy in 55 patients (37 Stage III). The median radiation dose to the tumor was 50 Gy (30-70 Gy). Supraclavicular radiation was performed in 59 patients (median dose 40 Gy). Chemotherapy, combined with radiation in 59 patients, consisted of multidrug regimens, mainly platinum based.

RESULTS

The median follow-up is 105 months (20-165 months). The 5- and 10-year overall survival rates are 51 and 39%, respectively. There is a great impact of the extent of surgery on survival: the 5- and 10-year survival rates were 64% and 43%, respectively, after partial resection, compared to 39% and 31% after biopsy (p < 0.02). Local control at 8.5 years was obtained in 59 of 90 patients (66%): 40 Stage III, 19 Stage IVA. There is a significant relationship between the extent of surgery and the local control (16% of relapse after partial resection vs. 45% after biopsy, p < 0.05). Seven patients developed significant (grades 3-4 WHO grading system) treatment-induced side effects. Stage, histologic type, and chemotherapy were not prognostic factors.

CONCLUSION

In this large multicentric retrospective study of invasive thymomas (Stage III-IVA) treated by surgery and radiation, results show the importance of loco-regional treatments, such as surgery and radiation therapy. There is also a great impact of radiation on local control. However, the rate of local recurrence (34%) justifies recommending a higher dose of radiation (> 50 Gy) than doses used in this study, for incompletely resected patients. The role of chemotherapy needs to be further assessed.

Late recurrence of thymoma and myasthenia gravis

In a case of thymoma associated with myasthenia gravis, symptoms of relapse appeared 14 years after thymectomy. Tumour tissue from repeat resection showed the same histologic pattern and aneuploidy as in the original specimen. The case illustrates the necessity of wide surgical exposure to permit maximal thymectomy, though recurrence remains possible.

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.