Multidisciplinary approach for advanced stage thymic tumors: Long-term outcome

Surgical, Radiation, and Systemic Treatments of Patients With Thymic Epithelial Tumors: A Systematic Review

INTRODUCTION

Thymic epithelial tumors are rare and are classified as thymoma, thymic carcinoma, and thymic neuroendocrine tumors. The objective of this systematic review was to evaluate the treatment options for patients with thymic epithelial tumors.

METHODS

This systematic review was developed by Ontario Health (Cancer Care Ontario)'s Program in Evidence-Based Care and by the Lung Cancer Disease Site Group. MEDLINE, EMBASE, and the Cochrane Library were searched for studies comparing surgical, radiotherapy, or systemic treatments against any combination of these treatments in patients with thymic epithelial tumors. Meta-analyses were conducted with clinically homogenous studies.

RESULTS

A total of 106 studies were included, mainly from observational studies. There was an overall survival benefit with postoperative radiotherapy for patients with thymic carcinoma (hazard ratio = 0.65, 95% confidence interval: 0.47-0.89) and for patients with thymoma (hazard ratio = 0.70, 95% confidence interval: 0.59-0.82), especially for those with a high risk for mortality. Patients with thymic carcinoma or thymoma had a response to chemotherapy. Selection bias affected the results for studies that evaluated neoadjuvant chemotherapy or minimally invasive surgical techniques. Furthermore, the overall survival benefit found for adjuvant chemotherapy may have been confounded by the administration of postoperative radiotherapy.

CONCLUSIONS

For patients with thymoma or thymic carcinoma, the literature is of low quality and subject to bias. There were overall survival benefits with postoperative radiotherapy. The results of this systematic review were used to inform treatment recommendations in a clinical practice guideline. Future large-scale prospective studies that control for confounders are needed.

Salvage Chemotherapy in Patients with Previously Treated Thymic Carcinoma

Thymic carcinoma is a rare neoplasm, and it is difficult to achieve complete remission with systemic chemotherapy. In advanced or recurrent thymic carcinoma, platinum-based chemotherapy is chosen as the first-line setting; however, it remains unclear which regimen is better to improve its outcome. It remains unknown whether salvage chemotherapy should be administered to patients with platinum-based chemotherapy-refractory thymic carcinoma. Currently, several clinical studies have investigated the efficacy of second-line settings for advanced thymic carcinoma. As cytotoxic agents, S-1, amrubicin, pemetrexed, docetaxel, paclitaxel, and gemcitabine have been reported as prospective phase II studies or retrospective studies. The overall response rates (ORRs) of S-1, amrubicin, and pemetrexed were 25-50%, 11-44.4%, and 9-10%, respectively. Molecular targeting drugs, such as sunitinib, everolimus, and lenvatinib, also provide clinical effectiveness with tolerability after the failure of platinum-based regimens. Based on the results of the prospective phase II study, the ORR, median progression-free survival, and median overall survival were 16.6% and 5.6 months, respectively, in everolimus, 26% and 7.2 months, respectively, in sunitinib, and 38% and 9.3 months, respectively, in lenvatinib. Although it is difficult to compare each study, lenvatinib appears to be better in increasing efficacy as a second-line setting. However, each study had a small sample size, which may have biased the results of their studies. Further investigation is warranted to elucidate the therapeutic significance of salvage chemotherapy in advanced thymic carcinoma in a large-scale study.

Surgical management of thymic epithelial tumors

Resection is the mainstay of treatment for thymic epithelial tumors (TETs), with complete removal of the tumor and involved organs being the ultimate aim. The choice of surgical approach plays a major role in defining treatment success, and the optimal choice of method should thus provide an adequate surgical view to achieve complete tumor resection. While median sternotomy is considered the gold standard for access to the mediastinum, several minimally invasive approaches to thymectomy have been described, including video-assisted robotic-assisted thymectomy, although the oncological outcomes of that procedure remain unclear. A multimodal approach incorporating chemotherapy or chemoradiotherapy followed by extended surgery may improve resectability and outcomes for patients with advanced TETs. Surgical debulking is also reportedly acceptable for invasive thymoma because of its potential for achieving favorable outcomes. Re-resection is an acceptable option for patients with recurrent thymoma after initial resection, and repeat resection for recurrent pleural dissemination seems effective. Here, the literature on current clinical practices in the surgical management and treatment of TETs is reviewed.

Two-year disease remission of an unresectable basaloid thymic carcinoma with second line chemotherapy drugs: report of a case

Thymic carcinomas are extremely infrequent neoplasms (15% of all thymic epithelial tumors). Basaloid carcinoma is a peculiar tumor that represents no more than 2% of those infrequent thymic carcinomas. Surgical excision is the recommended treatment. As it's extremely rare, there is no evidence of the impact of different modalities of treatment. There are no reported cases that did not include surgery as part of their management. We herein present a case of an unresectable thymic basaloid carcinoma treated only with concurrent chemotherapy and radiotherapy that obtained a complete remission and free of disease after 2 years.

Long-term outcomes of advanced thymoma in patients undergoing preoperative chemotherapy or chemoradiotherapy followed by surgery: a 20-year experience

OBJECTIVES

The results of preoperative chemotherapy or chemoradiotherapy followed by surgery for locally advanced thymoma were analysed.

METHODS

Between 1997 and 2016, 29 patients with a thymoma underwent preoperative chemotherapy or chemoradiotherapy followed by surgery. These cases were retrospectively reviewed.

RESULTS

The study population included 9 men and 20 women, with a mean age of 48.8 years (range 31-68 years). The preoperative Masaoka stage was III in 12, IVa in 13 and IVb in 4 patients, whereas histological type was B3 in 11, B2 in 9 and others in 5 patients. The mean tumour size was 8.0 ± 2.5 cm (3.4-15.0 cm). The site of infiltration shown in preoperative radiological examinations was the aorta in 6 patients, the superior vena cava in 14 patients and the pulmonary artery trunk in 3 patients, with pleural dissemination detected in 14. Three patients underwent chemoradiotherapy. Chemotherapy regimens given were cisplatin + doxorubicin + vincristine + cyclophosphamide in 9 patients, carboplatin + paclitaxel in 6 patients, cisplatin + doxorubicin + methylprednisolone in 5 patients and others in 9 patients, with partial response obtained in 11 patients and stable disease noted in 18 patients. Complete resection was achieved in 24 (83%) cases. There were no perioperative mortalities, whereas 6 (21%) patients developed postoperative complications. The 5- and 10-year overall survival rates were 100% and 87%, respectively, and 5- and 10-year disease-free survival rates were 50% and 50%, respectively.

CONCLUSIONS

Preoperative chemotherapy or chemoradiotherapy followed by surgery for locally advanced thymoma can be performed with an acceptable degree of surgical risk. Such a strategy should be proactively considered, as it can lead to favourable long-term results.

Comparison of Neoadjuvant Chemotherapy Followed by Surgery to Upfront Surgery for Thymic Malignancy

BACKGROUND

The oncologic benefit of neoadjuvant chemotherapy in thymic malignancies remains unclear. Postoperative oncologic outcomes of curative resection after neoadjuvant chemotherapy were compared with those of upfront surgery.

METHODS

Based on records from a multicenter database, 1,486 patients with surgically resected thymic malignancies between 2000 and 2013 were included in the final study cohort. Of these, 110 patients (7.4%) underwent surgical resection after neoadjuvant chemotherapy, and 1,376 patients (92.6%) underwent upfront surgery. A propensity score-matched analysis was performed to minimize differences in preoperative and intraoperative variables. Postoperative outcomes and survivals were compared between the two groups.

RESULTS

In the matched cohort, there were no significant differences in postoperative mortality (p value not calculated), postoperative complications (p = 0.405), and hospital length of stay (p = 0.821) between the two groups. However, the neoadjuvant chemotherapy group showed significantly higher transfusion rates (p = 0.003) and longer operation times (p < 0.001) than the upfront surgery group. Pathologically complete resection rates (p = 0.382) and tumor sizes (p = 0.286) were similar between the two groups. The 5-year overall survival rates were 77.4% and 76.7%, respectively (p = 0.596). The 3-year recurrence-free survival rates were 62.9% and 71.5%, respectively (p = 0.070).

CONCLUSIONS

Neoadjuvant chemotherapy, followed by resection, obtained similar resectability and long-term survival rates to those of upfront surgery. Therefore, the role of neoadjuvant chemotherapy should be refined in randomized controlled trials.

Chemoradiotherapy for unresectable cases of thymic epithelial tumors: a retrospective study

BACKGROUND

Because of the rarity of thymic epithelial tumors (TETs), there is no treatment for managing unresectable tumors that is supported by a high level of evidence. We present here the clinical outcomes of concurrent or sequential chemoradiotherapy for patients with unresectable TETs.

METHODS

We collated records for 215 patients with TETs who were treated at our institution and focused on the 20 patients who underwent chemoradiotherapy without curative-intent surgical resection.

RESULTS

Six patients with thymoma (4%) and 14 patients with thymic carcinoma (19%) were treated with chemoradiotherapy. Six received concurrent therapy, and platinum-containing regimens were administered to 16 patients. The survival of patients with thymic carcinoma was poorer than that of patients with thymoma [median overall survival (OS), 64.1 and 31.4 months, respectively; P=0.059]. No significant difference in survival was observed between patients treated concurrently and sequentially (48.5 vs. 38.2 months, respectively, P=0.83) or between patients treated with platinum-containing regimens and other regimens (43.5 and 53.8 months, respectively, P=0.25).

CONCLUSIONS

Chemoradiotherapy for unresectable TETs can be beneficial, especially when administrated concurrently. Patients for concurrent chemoradiotherapy should be chosen carefully because of its effectiveness and toxicity.

Pretreatment biopsy for histological diagnosis and induction therapy in thymic tumors

BACKGROUND

This study was to investigate the value of pretreatment biopsy for histological diagnosis and induction therapies in the management of locally advanced thymic malignancies.

METHODS

The clinical pathological data of patients with thymic tumors in the Chinese Alliance for Research in Thymomas (ChART) who underwent biopsy before treatment from 1994 to December 2012 were retrospectively reviewed. The application trend of preoperative histological diagnosis and its influence on treatment outcome were analyzed.

RESULTS

Of 1,902 cases of thymic tumors, 336 (17.1%) had undergone biopsy for histological diagnosis before therapeutic decision was decided. In recent years, percentage of pretreatment histological diagnosis significantly increased in the later ten years than the former during the study period (P=0.008). There was also a significant increase in thoracoscopy/mediastinoscopy/E-BUS biopsy as compared to open biopsy (P=0.029). Survival in Patients with preoperative biopsy for histology had significantly higher stage lesions (P=0.000) and higher grade malignancy (P=0.000), thus a significantly lower complete resection rate (P=0.000) and therefore a significantly worse survival than those without preoperative biopsy (P=0.000). In the biopsied 336 patients, those who received upfront surgery had significantly better survival than those received surgery after induction therapy (P=0.000). In stage III and IVa diseases, the R0 resection rate after induction therapies increased significantly as compared to the surgery upfront cases (65.5% vs. 46.2%, P=0.025). Tumors downstaged after induction had similar outcomes as those having upfront surgery (92.3% vs. 84.2%, P=0.51). However, tumors not downstaged by induction had significantly worse prognosis than those downstaged (P=0.004), and fared even worse than those having definitive chemoradiation without surgery (37.2% vs. 62.4%, P=0.216).

CONCLUSIONS

It is crucial to get histological diagnosis for thymoma before surgery or adjuvant treatment and minimally invasive biopsy should be undertaken. Although in our study we could not find the benefit of induction chemotherapy before surgery in survival and recurrence rate, it could increase the R0 resection rate compared with direct surgery in late stage (III and IVa).

Chemotherapy with paclitaxel plus carboplatin for relapsed advanced thymic carcinoma

OBJECTIVE

For rarity of thymic carcinoma, no definitive chemotherapeutic regimen has been established in second- or further-line settings. The aim of this study was to evaluate the feasibility and safety of paclitaxel plus carboplatin in advanced thymic carcinoma as second- or further-line treatment in our institute.

METHODS

We evaluated the efficacy and toxicity of paclitaxel plus carboplatin as salvage therapy in 12 patients with previously treated advanced thymic carcinoma from 2005 to 2012 in Zhejiang Cancer Hospital. Survival analysis was evaluated by Kaplan-Meier method.

RESULTS

Twelve patients were included in current study. Four patients achieved stable disease (SD), and three achieved partial response (PR), representing a response rate of 25.0% and disease control rate (DCR) of 58.3%. Median progression-free survival (PFS) and overall survival (OS) were 3.5 and 24.0 months, respectively. The toxicities associated with the paclitaxel plus carboplatin was generally acceptable.

CONCLUSIONS

Paclitaxel plus carboplatin appears to have some activity against thymic carcinoma as second-line or later chemotherapy in advanced thymic carcinoma.

Multimodality treatment for advanced thymic carcinoma: outcomes of induction therapy followed by surgical resection in 16 cases at a single institution

OBJECTIVE

We reviewed our institutional experience with cases of multimodality treatment for advanced thymic carcinoma to determine patient outcomes and prognostic indicators.

METHODS

Between 1998 and 2014, 16 patients with a Masaoka stage III or IV thymic carcinoma underwent surgical resection after induction therapy at Osaka University Hospital. These were considered to have great vessel invasion or metastasis to the mediastinal or intrathoracic lymph nodes based on the preoperative workup findings, and received induction therapy.

RESULTS

Complete tumor resection was achieved in 11 (69%) after the induction therapy. Pathological findings revealed that 10 patients had Masaoka stage III disease, 1 had IVa, and 5 had IVb. The histological diagnosis was squamous cell carcinoma in 13, neuroendocrine carcinoma in 2, and undifferentiated carcinoma in 1. The 5-year survival rate for all patients was 71%. Survival was significantly better in patients who underwent a complete resection (R0 disease) as compared to those with incompletely resected tumors (R1 or R2 disease).

CONCLUSIONS

Multimodality treatment offers encouraging results and complete resection provides high survival rate for patients with advanced thymic carcinoma.

Successful Concurrent Chemoradiotherapy with Cisplatin plus Vinorelbine for Locally Advanced Thymic Carcinoma

Little information is available about the usefulness of concurrent chemoradiotherapy for locally advanced thymic carcinoma due to a rare anterior mediastinal tumor. We experienced a case of locally advanced thymic carcinoma that responded well to concurrent thoracic radiotherapy combined with cisplatin plus vinorelbine chemotherapy. The patient showed remarkable tumor regression and has remained disease free for over 4 years following combined therapy. Concurrent chemoradiotherapy seems to be effective for locally advanced thymic carcinoma, and cisplatin plus vinorelbine could be an alternative chemotherapy regimen in combination with thoracic radiotherapy in patients with thymic carcinoma.

Chemotherapy for thymic carcinoma and advanced thymoma in adults

BACKGROUND

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

OBJECTIVES

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

SEARCH METHODS

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

SELECTION CRITERIA

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

DATA COLLECTION AND ANALYSIS

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

MAIN RESULTS

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

AUTHORS' CONCLUSIONS

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