Long-term survival and prognostic factors in thymic epithelial tumours.

OBJECTIVE: The aim of this study is to analyze long-term survival and the prognostic significance of some factors after surgical resection of thymic epithelial tumours. METHODS: We performed a retrospective analysis of clinical and histopathological data on 132 patients operated on for thymic tumours, from 1970 and 2001. Histologic diagnosis based on the new WHO classification system was made by a single pathologist. A univariate and multivariate analysis of prognostic factors predicting survival was carried out. RESULTS: There were: 108 complete resections (81.8%), 12 partial resections (9.1%) and 12 biopsies (9.1%). Overall 5, 10 and 15-year survival rate was 72, 61 and 52.5%, respectively. The Masaoka staging system showed 44 stage I, 18 stage II, 52 stage III and 18 stage IV. Histologic results were: 14 subtype A, 31 AB, 20 B1, 28 B2, 29 B3 and 10 C; the respective proportions of invasive tumour (stage II-IV) was 28.6, 58.1, 50, 75, 86.2 and 100%. There were 16 tumour recurrences (14.8%) of 108 radically resected thymomas, 10 were treated with radical re-resection. In univariate analysis, four prognostic factors were statistically significant: radical resection, Masaoka clinical staging, WHO histologic subtype and resectable tumour recurrence. In multivariate analysis, the independent factors predicting long-term survival were WHO histology and Masaoka stage. CONCLUSIONS: The WHO histologic classification seems to be the most significant prognostic factor reflecting the invasiveness of the thymic tumour. Completeness of resection and Masaoka stage I and II assure a better survival. Unresectable recurrence of thymic tumour predicted a worse prognosis.     

Clinical usefulness of the WHO histological classification of thymoma.

PURPOSE: Rosai et al. published the World Health Organization (WHO) classification of thymic epithelial tumors in 1999, and its clinical usefulness seems to be established. It is our purpose to find the clinically relevant diagnostic points in the WHO Histological Classification of Thymoma. METHODS: Thymomas surgically removed from 100 consecutive patients at Juntendo University Hospital between October 1983 and February 2002 were classified according to the WHO histological classification. We assessed overall survival and recurrence-free rate calculated for each tumor type in the WHO classification compared with those of tumors classified by the Masaoka system. RESULTS: The thymic epithelial tumors in this series comprised 10 type A, 15 type AB, 18 type B1, 21 type B2, 33 type B3, and 3 type C tumors according to the WHO classification. Based on the Masaoka system, the disease was stage I in 53 patients, stage II in 30, stage III in 15, and stage IV in 2. The 15-year recurrence-free rate was 100% for type A, AB and B1, while the rates for types B2 and B3 were 66.7% and 54.5%, respectively. The 10-year recurrence-free rate was 66.7% for type C. The 15-year recurrence-free rate of the 64 patients with type A, AB, B1, and B2 thymomas was significantly higher from that of the 33 patients with type B3 thymoma (p=0.0026). CONCLUSION: When using the WHO classification, it is critical to distinguish type B3 thymoma from other tumor types.     

Prognosis of surgically treated thymic epithelial tumors

This study was performed to clarify the prognosis of patients with surgically treated thymic epithelial tumors. The records of 131 patients who underwent surgical treatment during 1985-2005 were retrospectively reviewed. Pathologic review was done according to the WHO classification of tumors of the thymus. Patients characteristics were: 76 male and 55 fimale; average age 53 (range 20-80) years; tumor stage was stage I in 42, stage II in 43, stage III in 23, stage IVa in 15, stage IVb in 1, and thymic carcinoma (squamous cell carcinoma) in 7 based on Masaoka's staging. There were 7 cases of type A, 23 of type AB, 30 of type B1, 27 of type B2, 29 of type B3, and 15 of type C. Surgical procedures performed were 5 partial resections, 5 tumoretomies, 5 thymectomies, 65 extended thymectomies, 4 tumorectomies plus adjunctive resections of surrounding tissue, and 51 extended thymectomies plus tumorectomies plus adjunctive resections of surrounding tissue including the pleura, pericardium, lung, and great vessels. Five-, 10-, and 15-year survival rates by Masaoka stage were 100%, 100%, and 100% in stage I; 100%, 100%, and 87.5% in stage II; 100%, 87.5%, and 87.5% in stage III; 71.1%, 53.3%, and 53.3% in stage IVa; and 42.9%, 42.9%, and 0% in thymic carcinoma. The prognosis of patients with stage IVa and thymic carcinoma was thus significantly poorer compared with that in the other groups. According to the WHO classification, the 5-year survival rate of type A was 100%, and the 5-, 10-, and 15-year survival rates were 100%, 100%, and 100% in type AB; 100%, 100%, and 75.0% in type B1; 92.6%, 86.4%, and 86.4% in type B2; 95.5%, 95.5%, and 81.8% in type B3; and 57.1%, 42.9%, and 0% in type C. The survival rate of patients with type C was the poorest and there was a significant difference between type C and all other groups. The prognosis of patients with thymic epithelial tumors after resection is thought to be determined by histologic classification and clinical invasiveness. In particular, patients with type B3 and type C thymomas should be considered for multidisciplinary treatment.     

Oncological significance of WHO histological thymoma classification

OBJECTIVES: The clinical significance of thymoma histology remains controversial because of the numerous histological classifications of thymic epithelial tumors. Universal classification of such tumors was achieved by the World Health Organization (WHO) in 1999. We studied the prognostic significance of this classification. METHODS: We studied clinical features and postoperative survival in cases of thymoma, but not thymic carcinoma, based on WHO histological classification in 286 patients undergoing surgery between 1958 and 2001. RESULTS: Tumors were 19 type A, 79 type AB, 59 type B1, 102 type B2, and 27 type B3. The proportion of invasive tumors increased by type--from A to AB, B1, B2, and B3. The great vessels were involved more frequently in type B2 and B3 tumors than in type A, AB, and B1 tumors. The 20-year survival was 100% in type A, 87% in type AB, 91% in type B1, 65% in type B2, and 38% in type B3 tumors. Multivariate analysis showed Masaoka staging and WHO histological classification to be significant independent prognostic factors, while age, gender, myasthenia gravis association, resection completeness and great vessel involvement were not. In stage III patients, 13 of 45 patients with type B2 and B3 tumor died of their tumors, while no tumor deaths occurred in 11 patients with type A, AB, and B1 tumors. CONCLUSION: WHO histological classification realistically reflects the oncological behavior of thymoma.     

Surgery for thymomas and thymic carcinomas; treatment results in terms of WHO histologic typing,Masaoka staging system,and p53 expression

Forty thymomas and thymic carcinomas were classified in terms of WHO histologic typing, Masaoka staging system, and p53 expression. In WHO histologic typing, type A, AB, B1, B2, B3, and C were 1, 10, 16, 5, 4, and 4 cases, respectively. In Masaoka staging system, I, II, III, and IV were 15, 9, 10, and 6 cases, respectively. Thirteen thymomas exhibited positive p53 expression and 27 did not. Type A and AB thymomas had more favorite prognosis than type B3 and C thymomas, and prognosis of type B1 and B2 was middle. Staging by the Masaoka system also correlated with survival rates. Patients who had p53-negative thymomas survived longer than those who had p53-positive thymomas. A treatment strategy for thymomas and thymic carcinomas should be made on the basis of WHO histologic typing, Masaoka staging system, and p53 expression.     

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.     

Prognostic relevance of Masaoka and Müller-Hermelink classification in patients with thymic tumors

BACKGROUND: To compare the prognostic relevance of Masaoka and Müller-Hermelink classifications. METHODS: We treated 71 patients with thymic tumors at our institution between 1980 and 1997. Complete follow-up was achieved in 69 patients (97%) with a mean follow up-time of 8.3 years (range, 9 months to 17 years). RESULTS: Masaoka stage I was found in 31 patients (44.9%), stage II in 17 (24.6%), stage III in 19 (27.6%), and stage IV in 2 (2.9%). The 10-year overall survival rate was 83.5% for stage I, 100% for stage IIa, 58% for stage IIb, 44% for stage III, and 0% for stage IV. The disease-free survival rates were 100%, 70%, 40%, 38%, and 0%, respectively. Histologic classification according to Müller-Hermelink found medullary tumors in 7 patients (10.1%), mixed in 18 (26.1%), organoid in 14 (20.3%), cortical in 11 (15.9%), well-differentiated thymic carcinoma in 14 (20.3%), and endocrine carcinoma in 5 (7.3%), with 10-year overall survival rates of 100%, 75%, 92%, 87.5%, 30%, and 0%, respectively, and 10-year disease-free survival rates of 100%, 100%, 77%, 75%, 37%, and 0%, respectively. Medullary, mixed, and well-differentiated organoid tumors were correlated with stage I and II, and well-differentiated thymic carcinoma and endocrine carcinoma with stage III and IV (p < 0.001). Multivariate analysis showed age, gender, myasthenia gravis, and postoperative adjuvant therapy not to be significant predictors of overall and disease-free survival after complete resection, whereas the Müller-Hermelink and Masaoka classifications were independent significant predictors for overall (p < 0.05) and disease-free survival (p < 0.004; p < 0.0001). CONCLUSIONS: The consideration of staging and histology in thymic tumors has the potential to improve recurrence prediction and patient selection for combined treatment modalities.     

Clinical and functional aspects of the World Health Organization histologic classification of thymic epithelial tumors

The World Health Organization (WHO) histologic classification was presented by the international committee to provide a universal system for clinicians and researchers in 1999 and was further modified in 2004. This classification is mainly based on Müller-Hermelink et al.'s system and six distinct types were defined. Thymomas were classified into type A, AB, B1, B2, and B3 tumors, according to the shape and atypia of epithelial cells and also the abundance of lymphocytes. Another type of tumor is thymic carcinomas, which have apparent atypia of neoplastic cells. Neuroendocrine tumor (carcinoid) of the thymus was categorized as thymic carcinoma because of the resemblance of genetic aberrations. Several studies have shown that the WHO histologic type is correlated with the proportion of invasive tumors and is an independent prognostic factor along with Masaoka stage. Furthermore, association with myasthenia gravis, ability to induce CD4+CD8+T cells and express HLA-DR molecules, and chromosomal imbalances such as loss of heterogeneity were found to be correlated with the WHO histologic type. Thus, the WHO histologic classification system reflects the oncologic, immunologic, and genetic characteristics of thymic epithelial tumors. The clinical application of this classification system is expected.     

Prognostic significance of CD44v5 expression in human thymic epithelial neoplasms

BACKGROUND: Cell surface glycoproteins of the CD44 family play roles in cell-cell and cell-matrix interactions. Their aberrant expression has been implicated in tumor invasion and metastasis of a variety of neoplasms, but not, to date, of thymic epithelial tumors. METHODS: To investigate the expression of CD44 molecules, immunohistochemical staining using monoclonal antibodies against human CD44 standard form (CD44 s) and two common splicing variant (CD44v) isoforms, CD44v5 and CD44v6, was performed on 64 resected thymomas and 20 normal thymuses. These tumors were categorized histologically according to the World Health Organization (WHO) histologic classification, and the pathologic staging was classified according to the definitions of Masaoka. RESULTS: The positive expression rates in these patients were as follows: CD44 s (normal thymuses, 10%; thymomas, 22%), CD44v5 (normal thymuses, 0%; thymomas, 67%), and CD44v6 (normal thymuses, 0%; thymomas, 26%). CD44 s and CD44v5 immunoreactivity showed a positive correlation with tumor stages (p = 0.034 and 0.027, respectively). The CD44v5 expression of neoplastic cells in tumor capsules has significant correlation with tumor stages (II, 5%; III, 70%; IVA, 100%; p < 0.001). On the basis of univariate survival analysis, the Masaoka staging system, WHO histologic classification, and CD44v5 expression showed a statistically significant positive relation to survival (p < 0.001, 0.002, 0.011, respectively). Using Cox's regression model, increasing CD44v5 expression, the Masaoka staging, and the WHO classification system were found to be significant independent prognostic factors. CONCLUSIONS: CD44v5 expression is independently positively correlated with the aggressiveness of thymic epithelial tumors. The expression of CD44v5 may be a potential trigger of tumor invasion in thymomas.     

Thymoma needs a new staging system

Despite the wide use of the Masaoka staging system for thymoma, the distribution of survival by stage group is not well balanced. The new staging systems for testing were defined as follows: stage I was created by merging Masaoka's stages I and II, and stage IV remained unchanged. Stages II and III were defined as thymomas with invasive growth and the following combinations of tumor diameter and number of involved structures/organs. Scheme 1: stage II included tumors less than 10 cm in diameter and involving one neighboring structure/organ. Stage III included tumors with all combinations of diameter and number of involved structures/organs other than those in stage II. Scheme 2: stage II included tumors of all combinations other than those in stage III. Stage III included tumors 10 cm or more in diameter and involving two or more structures/organs. The survival curves were assessed for 138 patients treated at the National Cancer Center, Tokyo. The 10-year survival rates for each stage according to the Masaoka, Scheme 1, and Scheme 2 systems were as follows: stage I (100%, 100%, 100%), stage II (100%, 86%, 83%), stage III (70%, 64%, 34%), and stage IV (34%, 34%, 34%), respectively. The survival curves for Scheme 1 gave the most balanced distribution of survival in each staging group. By considering both tumor diameter and number of involved structures/organs, Masaoka's stages I-III could be rearranged with more balanced distribution of survival.     

Prognosis of thymic epithelial tumors according to the new World Health Organization histologic classification

Background

The aim of this study was to document the prognosis of thymic epithelial tumors (TETs) according to new the World Health Organization (WHO) classification.

Methods

We retrospectively reviewed 150 patients with TETs that were confirmed pathologically during 11 years (from 1992 to 2002) in Severance Hospital, Seoul, Korea.

Results

TETs were classified as type A, AB, B1, B2, B3, or C, tumors and these represented 7 (4.7%), 26 (17.3%), 13 (8.7%), 45 (30.0%), 26 (17.3%), and 33 (22.0%) cases, and the 5-year survival rates were 100%, 93%, 89%, 82%, 71%, and 23%, respectively. Their Masaoka stages were I, II, III, IVa, and IVb, with 53 (35.3%), 39 (26.0%), 20 (13.3%), 22 (14.7%), and 16 (10.7%) cases. Tumor invasiveness, recurrence, completeness of resection, and tumor-related death were more frequent in types AB, B2, B3, and C than in types A and B1. Multivariate analysis showed that Masaoka stage (p < 0.001) and the WHO classification (p = 0.019) were significant independent prognostic factors.

Conclusions

The WHO classification is associated with tumor invasiveness, recurrence, completeness of resection, and tumor-related death, and has good correlation with Masaoka stage. The WHO histologic subtypes are an independently significant prognostic factor with respect to survival in our multivariate analysis. Types AB, B2, B3, and C showed invasive behaviors and R1 or R2 resections were frequently performed. Postoperative adjuvant radiotherapy was effective, but long-term follow-up is recommended because of decreased survival after 5 years following operation. The WHO classification may be helpful in clinical practice for the assessment and treatment of TET patients.     

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.     

Therapy for thymic epithelial tumors: a clinical study of 1,320 patients from Japan

BACKGROUND: Surgery remains the mainstay of treatment for thymic epithelial tumors, and radiation and chemotherapy also have been applied widely as adjuvant and palliative procedures. METHODS: We compiled records of 1,320 patients with thymic epithelial tumors who were treated from 1990 to 1994 in 115 institutes certified as special institutes for general thoracic surgery by The Japanese Association for Chest Surgery. RESULTS: Patients with stage I thymoma were treated with only surgery, and patients with stage II and III thymoma and thymic carcinoid underwent surgery and additional radiotherapy. Patients with stage IV thymoma and thymic carcinoma were treated with radiation or chemotherapy. The Masaoka clinical stage is an excellent predictor of the prognosis of thymoma and thymic carcinoma, but not thymic carcinoid. In stage III and IV thymoma, the 5-year survival rates of total resection, subtotal resection, and inoperable groups were 93%, 64%, and 36%, respectively. On the other hand, in thymic carcinoma, the 5-year survival rates of total resection, subtotal resection, and inoperable groups were 67%, 30%, and 24%, respectively. Prophylactic mediastinal radiotherapy could not prevent local recurrences effectively in patients with totally resected stage II and III thymoma. Adjuvant therapy including radiation or chemotherapy did not improve the prognosis in patients with totally resected III and VI thymoma and thymic carcinoma. CONCLUSIONS: Total resection is the most important factor in the treatment of thymic epithelial tumors. There is value in debulking surgery in invasive thymoma, but not in thymic carcinoma. We doubt that adjuvant therapy is valuable for patients with totally resected invasive thymoma and thymic carcinoma.     

Clinicopathological character and long-term results of thymic epithelial tumor categorized by WHO classification

We analyzed clinicopathological character and long term results of 50 thymic epithelial tumors with reference to WHO histologic classification. There were 1 type A tumor, 8 type AB tumors, 13 type B1 tumors, 16 type B2 tumors, 10 type B3 tumors, and 2 type C tumors. Clinical stages were progressive in order of classification type A, AB, B1, B2, B3, and C. Type B1 and B2 were highly associated with myasthenia gravis (MG). There were four multiple thimic tumor in patients of advance clinical stage with polygonal epithelial cell tumor. Long term results were poor in order of the classification of type A, AB, B1, B2, B3, and C. In our study, WHO classification finely reflected the clinical character and prognosis of thymic epithelial tumors.     

Results of surgical treatment for thymic epithelial tumors with special reference to the WHO classification

We examined the clinical significance of World Health Organization (WHO) classification based on a surgical experience with 71 patients. There were 6, 21, 6, 10, 14, and 14 patients with type A, AB, B1, B2, B3 and C tumors. In these patients, average stage by Masaoka's classification was significantly associated with the WHO classification. Invasive tumors of stage III and IV were seen more frequently in patients with type B2, B3 and C tumors than in those with type A, AB and B1. The incidence of tumors invading the lung, the pericardia or the pleura was higher in type B2, B3 and C than in type A, AB or B1. Furthermore, tumor recurrences and tumor-related deaths were seen only in patients with type B2, B3 or C. This study suggested that type B2, B3 and C tumors had more malignant nature in terms of invasiveness, recurrence and prognosis following operation, and that WHO classification may be a useful guideline for planning treatment of thymic epithelial tumors.     

Multicenter Institutional Experience of Surgically Resected Thymic Epithelial Tumors (TETs): An Observational Report on Behalf of F.O.N.I.C.A.P. (Forza Operativa Nazionale Interdisciplinare Contro il Cancro del Polmone)

Background

This multicenter analysis evaluated patient outcome and clinical pathologic features of thymic epithelial tumors after complete surgical resection and adjuvant treatment.

Methods

Histologic classification and clinical staging were performed according to WHO classification and Masaoka staging system, respectively.

Results

We analyzed 62 patients, 20 (32 %) of whom had myasthenia at diagnosis. Clinical and pathologic staging was as follows: 31 (50 %) and 30 (48 %) patients had stage I disease, 19 (30 %) and 22 (35 %) stage II, 5 (8 %) and 3 (6 %) stage III, 2 (4 %) and 2 (3 %) stage IVa, and 5 (8 %) and 5 (8 %) stage IVb, respectively. Histologic examination revealed 11 (19%) type A tumors, 19 (30%) type AB tumors, 7 (12 %) type B1 tumors, 11 (17 %) type B2 tumors, 11 (17 %) type B3 tumors, and 3 (5 %) type C tumors. Adjuvant therapies comprised chemotherapy in 3 (5 %) patients and radiotherapy in 16 (26 %) patients. Median follow-up was 71 months (range 1–145). DFS and OS at 48, 60, and 72 months were 89 and 89 %, 86 and 97 %, and 95% and 92%, respectively. Myasthenia at the onset of disease (P = 0.18 for DFS; P = 0.97) and tumor size >5 cm (P = 0.94 for DFS; P = 0.56) were not prognostic factors.

Conclusions

TETs are rare and indolent tumors. Complete surgical resection followed by adjuvant therapies, such as chemotherapy and/or radiotherapy, in patients at risk of recurrence show very good DFS and OS results, even in cases with radically resected pleural-pulmonary metastases.     

Thymoma--a retrospective study of 48 cases

Of the 48 thymomas operated on between 1968 and 1985 50% were associated with myasthenia gravis, in 25% diagnosis was made due to accidental X-ray findings. In the staging according to Masaoka et al. [10] the following distribution was noted: I:22, II:5, III:18, IV:3. The 5-year survival rate of the 37 curatively resected patients was 78.5% (stage I: 88.6%, stage III: 55.6%). No stage III patient with residual tumor survived more than 2 years. Predominantly epithelial tumors had a significantly worse prognosis as compared to those with lymphocytic predominance. None of the 4 patients with category II thymoma survived more than 15 months. Association with myasthenia proved to have a negative prognostic influence in stage I and II patients. Frequency of local recurrences and metastases is documented. The value of irradiation and chemotherapy is discussed.     

Clinical and functional significance of WHO classification on human thymic epithelial neoplasms: a study of 146 consecutive tumors

We examined the clinical and functional significance of histologic classification of thymic epithelial neoplasms proposed by the World Health Organization (WHO), based on an analysis of 146 consecutive tumors derived from 141 patients and 47 normal thymuses derived from children ranging in age from 1 to 9 years. Invasive tumors were seen in 12.5%, 38.6%, 40.0%, 69.4%, 80.0%, and 100% of type A, AB, B1, B2, B3, and C primary tumors, respectively. All of six recurrent or metastatic lesions were type B2 tumors. Myasthenia gravis was associated in 0%, 6.8%, 40.0%, 55.6%, 10.0%, and 0% in patients with type A, AB, B1, B2, B3, and C tumors, respectively. The average number (x10(6)) of tumor-associated CD4+CD8+ cells present in 1 g of tumor tissue was 1.5, 391.1, 1041.7, 333.9, 24.5, and 0.2 in type A, AB, B1, B2, B3, and C, respectively, and it was 1168.2 in the normal thymuses. Thus, type B1 tumor retained the function to induce CD4+CD8+ double-positive cells at a level comparable to that of the normal thymic cortical epithelial cells, followed by type AB and type B2 tumors. Type A and B3 tumors had this function at a barely detectable level, and type C tumor was nonfunctional. WHO histologic classification was shown to reflect the clinical features and the T-cell-inducing function of thymic epithelial tumors.     

Analysis of surgical treatment of Masaoka stage III-IV thymic epithelial tumors

Objective

The purpose of this study is to elucidate the outcomes after surgical resection of Masaoka stage III-IV thymic epithelial tumors.

Methods

We retrospectively reviewed patients with Masaoka stage III-IV thymic epithelial tumor who underwent surgical resection from January 1995 to January 2017. The clinicopathological features, surgical procedures, and postoperative outcomes were investigated.

Results

Thirteen patients with thymoma and 18 patients with thymic carcinoma were assessed. The postoperative Masaoka stages were III/IVa/IVb?=?8/4/1 in thymoma and III/IVa/IVb?=?11/2/5 in thymic carcinoma. In patients with thymoma, the World Health Organization pathological subtypes were A/B1/B2/B3?=?2/1/4/6. We performed combined resection and reconstruction for brachiocephalic vein or superior vena cava in 3 patients with thymoma and 7 patients with thymic carcinoma. In all patients, the patency rate of the grafts was very low for the left brachiocephalic vein and well maintained for the right brachiocephalic vein. Macroscopically and pathologically complete resection was achieved in 11 and 6 patients with thymoma, respectively, and in 15 and 9 patients with thymic carcinoma, respectively. The 10-year survival rates were 85.7% in thymoma and 70.3% in thymic carcinoma. Postoperative recurrences were observed in 2 and 9 patients with thymoma and thymic carcinoma, respectively. Recurrences were observed within 5 and 10 years after surgery in 2 patients with thymoma and within 2 years in all patients with thymic carcinoma.

Conclusions

Patients with Masaoka stage III-IV thymic epithelial tumor showed relatively favorable long-term survival after surgical treatment. Therefore, aggressive surgical resection for complete resection may be a treatment option for these conditions.

     

Surgical treatment of thymic cysts and neoplasms in children

Based on experience with 17 patients and review of the literature, complete excision is possible for all benign thymic cysts and neoplasms. Recurrence is rare (2%). Most malignant thymomas in children are epithelial (73%). As with adults, prognosis depends on accurate surgical staging and aggressive surgical intervention. Even the largest tumors can be completely excised removing portions of lung, pleura, diaphragm, and pericardium in continuity as required. Cardiopulmonary bypass may be necessary when the innominate veins or the superior vena cava is involved. Irradiation is required for stage II and stage III lesions. Stage IV patients require irradiation and chemotherapy.