Chemotherapy versus chemotherapy plus immune checkpoint inhibitors for the first-line treatment of unresectable thymic carcinoma: A multicenter retrospective study

Thymic carcinoma (TC) is a rare malignant tumor with a poor prognosis, and there is currently limited data on the use of immunotherapy in patients with unresectable TC. In this study, data of patients with unresectable TC diagnosed from January 2017 were retrospectively collected from multiple centers. Treatment response, progression-free survival (PFS), overall survival (OS), survival-independent prognostic factor, and adverse events (AEs) were further analyzed. As a result, a total of 93 patients with unresectable TC were enrolled, of which 54 received first-line chemotherapy, and 39 received chemotherapy plus immune checkpoint inhibitors (ICIs). The objective response rate was 50% (27/54) in the chemotherapy group and 76.9% (30/39) in the chemotherapy plus ICIs group. The chemotherapy plus ICIs group achieved significant median PFS benefit (8.8 vs. 34.9 months, p < .001) and median OS benefit (41.8 months vs. not reached, p = .025). Multivariate analysis showed that ICIs and local therapy were independent prognostic factors for PFS. In addition, 17 patients developed immune-related AEs (IRAEs), of which 15 (38.5%) had Grade 1 or 2 IRAEs and 2 (5.1%) had Grade 3 IRAEs in the chemotherapy plus ICIs group. In conclusion, the efficacy of chemotherapy plus ICIs is superior to chemotherapy, and the adverse effects are manageable in patients with unresectable TC.

Chinese expert consensus on the diagnosis and treatment of thymic epithelial tumors

Thymic epithelial tumors (TETs) are a relatively rare type of thoracic tumor, accounting for less than 1% of all tumors. The incidence of TETs is about 3.93/10000 in China, slightly higher than that of European and American countries. For resectable TETs, complete surgical resection is recommended. Radiotherapy or chemotherapy may be used as postoperative adjuvant treatment. Treatment for advanced, unresectable TETs consist mainly of radiotherapy and chemotherapy, but there is a lack of standard first- and second-line treatment regimens. Recently, targeted therapies and immune checkpoint inhibitors have shown promising outcomes in TETs. Based on the currently available clinical evidences and the opinions of the national experts, the Thymic Oncology Group of Yangtze River Delta Lung Cancer Cooperation Group (East China LUng caNcer Group, ECLUNG; Youth Committee) established this Chinese expert consensus on the clinical diagnosis and treatment of TETs, covering the epidemiology, diagnosis, treatment, prognosis and follow-up of TETs.

Combination carboplatin and nab-paclitaxel as a first-line treatment for advanced thymic carcinoma

Thymic carcinoma is a very rare neoplasm for which no optimal chemotherapeutic regimen has been established to date. Hence, we performed this study to investigate the efficacy and safety of carboplatin plus nanoparticle albumin-bound (nab)-paclitaxel as a first-line regimen for patients with advanced thymic carcinoma. We conducted this multi-institutional retrospective cohort study of patients with advanced thymic carcinoma who had received carboplatin plus nab-paclitaxel as a first-line chemotherapy between August 2013 and December 2021. Twelve patients were included in this study and were subjected to efficacy and safety analysis. Their median age was 62 years (range, 47-74 years), and all had an Eastern Cooperative Oncology Group performance status score of 0 or 1. After a median follow-up time of 19.7 months, the overall response rate was 50%; the median progression-free and overall survival times were 8.8 months and 23.3 months, respectively. Chemotherapy-related peripheral neuropathy was observed in 2 patients (16%; each with grade 1). Other toxicities were manageable, and there were no treatment-related deaths. Carboplatin plus nab-paclitaxel as a first-line chemotherapy regimen showed good efficacy and safety in patients with advanced thymic carcinoma.

Treatment outcomes and prognosis of immune checkpoint inhibitors therapy in patients with advanced thymic carcinoma: A multicentre retrospective study

BACKGROUND

Immunotherapy has demonstrated good efficacy and survival outcomes in solid tumours. However, efficacy data for immune checkpoint inhibitors (ICIs) in advanced thymic carcinoma are lacking. The present study aimed to assess the activity of ICIs in advanced thymic carcinoma.

METHODS

A multicentre retrospective study was conducted to explore the efficacy and safety of ICIs for advanced thymic carcinoma. Objective response rate (ORR), progression-free survival (PFS), overall survival, and immune-related adverse events (irAEs) were analysed. In addition, factors independently associated with treatment efficacy and survival outcomes were evaluated.

RESULTS

A total of 77 patients with advanced thymic carcinoma were enrolled between March 2016 and September 2021. The ORR was existing the difference between ICIs monotherapy (n = 23) and ICIs combined with chemotherapy (n = 54) (17.4% versus 44.4%, P = 0.024). The ICIs combination treatments were associated with better median PFS (mPFS) compared to ICIs monotherapy (12.7 months versus 2.1 months, P < 0.001). Notably, liver or brain metastasis was a poor prognostic factor of mPFS (1.8 months versus 3.5 months, P = 0.012) in the ICIs monotherapy group. In addition, mPFS for the first-line treatment (n = 27) was longer than that for ICIs as the second- or posterior-line treatment (n = 50) (P < 0.001). The incidence of irAEs was 54.5% (42/77) in the 77 enrolled patients. The incidence of grade 3-4 irAE was 15.6% (12/77).

CONCLUSIONS

Immunotherapy is effective in advanced thymic carcinoma, especially for combination with chemotherapy showed promising antitumour activity, which indicates worthy of combination treatment strategy for further study. IrAEs also require close monitoring and management.

A novel risk classifier for predicting the overall survival of patients with thymic epithelial tumors based on the eighth edition of the TNM staging system: A population-based study

OBJECTIVE

Thymic epithelial tumors (TETs) are rare tumors that originated from thymic epithelial cells, with limited studies investigating their prognostic factors. This study aimed to investigate the prognostic factors of TETs and develop a new risk classifier to predict their overall survival (OS).

METHODS

This retrospective study consisted of 1224 TETs patients registered in the Surveillance, Epidemiology, and End Results (SEER) database, and 75 patients from the First Affiliated Hospital of Xi'an Jiaotong University. The univariate and multivariate Cox regression analyses were adopted to select the best prognostic variables. A nomogram was developed to predict the OS of these patients. The discriminative and calibrated abilities of the nomogram were assessed using the receiver operating characteristics curve (ROC) and calibration curve. Decision curve analysis (DCA), net reclassification index (NRI), and integrated discrimination improvement (IDI) were adopted to assess its net clinical benefit and reclassification ability.

RESULTS

The multivariate analysis revealed that age, sex, histologic type, TNM staging, tumor grade, surgery, radiation, and tumor size were independent prognostic factors of TETs, and a nomogram was developed to predict the OS of these patients based on these variables. The time-dependent ROC curves displayed that the nomogram yielded excellent performance in predicting the 12-, 36- and 60-month OS of these patients. Calibration curves presented satisfying consistencies between the actual and predicted OS. DCA illustrated that the nomogram will bring significant net clinical benefits to these patients compared to the classic TNM staging system. The estimated NRI and IDI showed that the nomogram could significantly increase the predictive ability of 12-, 36- and 60-month OS compared to the classic TNM staging system. Consistent findings were discovered in the internal and external validation cohorts.

CONCLUSION

The constructed nomogram is a reliable risk classifier to achieve personalized survival probability prediction of TETs, and could bring significant net clinical benefits to these patients.

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.

Are Pt(IV) Prodrugs That Release Combretastatin A4 True Multi-action Prodrugs?

"Multi-action" Pt(IV) derivatives of cisplatin with combretastatin A4 (CA4) bioactive ligands that are conjugated to Pt(IV) by carbonate are unique because the ligand (IC₅₀ < 10 nM) is dramatically 1000-folds more cytotoxic than cisplatin in vitro. The Pt(IV)-CA4 prodrugs were as cytotoxic as CA4 itself, indicating that the platinum moiety probably plays an insignificant role in triggering cytotoxicity, suggesting that the Pt(IV)-CA4 complexes act as prodrugs for CA4 rather than as true multi-action prodrugs. In vivo tests (Lewis lung carcinoma) show that ctc-[Pt(NH₃)₂(PhB)(CA4)Cl₂] inhibited tumor growth by 93% compared to CA4 (67%), cisplatin (84%), and 1:1:1 cisplatin/CA4/PhB (85%) while displaying <5% body weight loss compared to cisplatin (20%) or CA4 (10%). In this case, and perhaps with other extremely potent bioactive ligands, platinum(IV) acts merely as a self-immolative carrier triggered by reduction in the cancer cell with only a minor contribution to cytotoxicity.

Radiotherapy for thymic epithelial tumours: a review

Thymic epithelial tumours (TETs) represent a rare disease, yet they are the most common tumours of the anterior mediastinum. Due to the rare occurrence of TETs, evidence on optimal treatment is limited. Surgery is the treatment of choice in the management of TETs, while the role of postoperative radiotherapy (PORT) remains unresolved. PORT remains debated for thymomas, especially in completely resected stage II tumours, for which PORT may be more likely to benefit in the presence of aggressive histology (WHO subtype B2, B3) or extensive transcapsular invasion (Masaoka-Koga stage IIB). For stage III thymoma, evidence suggests an overall survival (OS) benefit for PORT after complete resection. For incompletely resected thymomas stage II or higher PORT is recommended. Thymic carcinomas at any stage with positive resection margins should be offered PORT. Radiotherapy plays an important role in the management of unresectable locally advanced TETs. Induction therapy (chemotherapy or chemoradiation) followed by surgery may be useful for locally advanced thymic malignancies initially considered as unresectable. Chemotherapy only is offered in patients with unresectable, metastatic tumours in palliative intent, checkpoint inhibitors may be promising for refractory diseases. Due to the lack of high-level evidence and the importance of a multidisciplinary approach, TETs should be discussed within a multidisciplinary team and the final recommendation should reflect individual patient preferences.

Successful Treatment of Advanced Thymic Carcinoma with Carboplatin plus nab-Paclitaxel and Maintenance Monotherapy with nab-Paclitaxel: Two Case Reports

A standard chemotherapy regimen for advanced thymic carcinoma has not yet been established. We treated 2 cases of thymic carcinoma with carboplatin plus nanoparticle albumin-bound (nab)-paclitaxel, and nab−paclitaxel maintenance therapy. The first case was a 68-year-old female, admitted for dyspnea and left shoulder pain. Chest computed tomography (CT) showed a huge mass in the anterior mediastinum, pleural and pericardial effusions, and multiple lung metastases. Specimens obtained from the anterior mediastinal mass by CT-guided needle biopsy revealed squamous cell carcinoma of the thymus, which was in stage IVB. The patient was administered carboplatin plus nab−paclitaxel as first-line treatment. After 3 cycles of chemotherapy, a partial response was observed with marked shrinkage of the tumor. Following 6 cycles of chemotherapy, nab−paclitaxel maintenance therapy was initiated. Disease progression was seen 9.1 months after initiation of treatment. The patient experienced no serious adverse events. The second case was a 70-year-old male who had productive cough, dyspnea, and right-sided chest pain. Chest CT revealed a huge mass in the anterior mediastinum, pericardial effusion, and multiple lymphadenopathies. Specimens obtained from station 11s by endobronchial ultrasound-guided transbronchial needle aspiration revealed undifferentiated thymic carcinoma, which was in stage IVB. Six cycles of carboplatin plus nab−paclitaxel were administered, followed by 5 cycles of nab−paclitaxel for maintenance. A partial response was seen, which was sustained for more than 13 months. The patient experienced no serious adverse events. These cases show that chemotherapy with carboplatin plus nab−paclitaxel and nab−paclitaxel as maintenance therapy can be a useful regimen for advanced thymic carcinoma.

The treatment and survival of patients with postoperative recurrent thymic carcinoma and neuroendocrine carcinoma: a multicenter retrospective study

PURPOSE

There are few data available on the outcomes of postoperative recurrent thymic carcinoma (TC) and thymic neuroendocrine carcinoma (TNEC). The aim of this study is to evaluate the treatment and survival in patients with recurrent TC and TNEC after undergoing surgical resection.

METHODS

A retrospective chart review was performed using our multicenter database to identify patients with a postoperative recurrence of TC and TNEC from 1995 to 2018. The clinicopathological factors were reviewed and the survival outcomes were analyzed.

RESULTS

Sixty patients were identified among 152 patients who underwent resection of TC and TNEC. The median follow-up period from the first recurrence was 14.8 months (range 0-144). The 5-year post-recurrence survival was 23% for the whole cohort. According to a univariable analysis, advanced stage [hazard ratio (HR) 2.81, 95% confidence interval (CI) 1.09-9.54], interval between primary surgery and recurrence (HR 0.97, 95% CI 0.95-0.99), any treatment for recurrence (HR: 0.27, 95% CI 0.13-0.58) and chemotherapy for recurrence (HR: 0.46, 95% CI 0.22-0.95) were significant factors related to post-recurrence survival.

CONCLUSIONS

Chemotherapy rather than surgery appears to be the mainstay treatment for managing patients with postoperative recurrent TC and TNEC and it may also be considered in multidisciplinary management. Further studies with a larger sample size are required to confirm our findings.

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.

Optimal first-line treatment for advanced thymic carcinoma

Background

Thymic carcinomas (TCs) are rare aggressive tumors with no standard first‐line treatment. This study was conducted to determine the optimal chemotherapy regimen for advanced TC.

Methods

This retrospective study included 67 patients treated for stage IV TC in 2006–2015. The primary endpoints were the objective response rate (ORR) and progression‐free survival (PFS) with different chemotherapy regimens. Multivariate Cox regression analysis was used to identify factors associated with PFS, including metastatic status, radiotherapy post‐chemotherapy, primary lesion resection before chemotherapy, and chemotherapy regimen.

Results

A total of 36 patients received a paclitaxel‐platinum regimen, 31 received a gemcitabine‐platinum regimen, 14 underwent primary lesion resection, and 33 underwent radiotherapy. ORR was 31% (11/36) and 29% (9/31) in the paclitaxel‐platinum and gemcitabine‐platinum groups, respectively (P = 0.890). Median PFS, one‐year PFS rate, and two‐year PFS rate were 7.0 months, 26%, and 6% with paclitaxel‐platinum treatment and 12 months, 48%, and 24% with gemcitabine‐platinum treatment (log‐rank P = 0.030). Median PFS, one‐year PFS rate, and two‐year PFS rate were 18.0 months, 57%, and 33% with surgical resection and 7.3 months, 31%, and 7% without resection (log‐rank P = 0.030). Median PFS, one‐year PFS rate, and two‐year PFS rate were 13.0 months, 52%, and 20% with radiotherapy and 4.3 months, 22%, and 7% without radiotherapy (log‐rank P = 0.001). In multivariate analysis, metastatic status (hazard ratio [HR], 0.33, P = 0.004), surgical resection (HR, 0.32; P = 0.004), and radiotherapy (HR, 0.32; P < 0.001) were associated with superior PFS.

Conclusions

Both gemcitabine‐platinum and paclitaxel‐platinum regimens were efficacious for advanced TC. Primary lesion resection and radiotherapy may also benefit selected patients.

Expression Patterns, Prognostic Value, and Intratumoral Heterogeneity of PD-L1 and PD-1 in Thymoma and Thymic Carcinoma

INTRODUCTION

Thymic epithelial tumors (TETs) including thymoma and thymic carcinoma are rare tumors with little data available to guide treatment. Immunotherapy with checkpoint blockade has shown promising activity, but data regarding the expression patterns and prognostic implications of programmed death 1 (PD-1) and its ligand (PD-L1) in TETs have yielded conflicting results. Intratumoral heterogeneity of PD-1/L1 expression has been shown in other cancers, but has not been described in the TET literature.

METHODS

We performed a retrospective single-center review of 35 patients with resected TET. PD-1/L1 expression was assessed by immunohistochemistry using PD-1 clone: NAT105 and PD-L1 clone: 22C3. Tumor samples from 35 patients were evaluated including 32 patients with thymoma and 3 patients with thymic carcinoma.

RESULTS

PD-L1 expression was detected in 83% (29 of 35) tumor samples, including 100% (3 of 3) of thymic carcinoma patients and 81% (26 of 32) of thymoma patients. PD-1 expression was detected in 77% (27 of 35), including 33% (1 of 3) of thymic carcinoma patients and 81% (26 of 32) thymoma patients. High PD-1 expression was associated with lower grade tumors. Unlike prior studies, PD-L1 expression was not associated with higher grade tumors or higher stage. Neither PD-L1 nor PD-1 expression was significantly associated with survival. Three patients with thymoma had multiple tumor sections evaluated for expression of PD-1/L1, with differing expression patterns of both PD-L1 and PD-1 observed in two patients.

CONCLUSIONS

This study confirms high expression of PD-L1 and PD-1 in TET and shows for the first time intratumoral heterogeneity of PD-L1 and PD-1 in thymoma patients.

Prognostic Factors and Efficacy of First-Line Chemotherapy in Patients with Advanced Thymic Carcinoma: A Retrospective Analysis of 286 Patients from NEJ023 Study

BACKGROUND

The prognostic factors and the efficacy of first-line chemotherapy remain unclear in patients with advanced thymic carcinoma.

MATERIALS AND METHODS

We conducted a multi-institutional retrospective study named NEJ023 for patients with advanced thymic carcinoma. All patients without any indication of curative treatment were treated with chemotherapy from 1995 to 2014 at 40 institutions of the North East Japan Study Group.

RESULTS

A total of 286 patients with advanced thymic carcinoma were analyzed. First-line chemotherapy included platinum-based doublets in 62.2% of the patients, monotherapy in 3.5%, and other multidrug chemotherapy (e.g., cisplatin, doxorubicin, vincristine, and cyclophosphamide [ADOC]) in 34.3%. The median follow-up period was 55.5 months, and the median overall survival (OS) from the start of first-line chemotherapy was 30.7 months (95% confidence interval, 25.9-35.9 months). There was no significant difference in OS among different first-line chemotherapy regimens (e.g., between carboplatin/paclitaxel and ADOC, median OS: 27.8 vs. 29.9 months). Masaoka-Koga stage IVa and volume reduction surgery were favorable prognostic factors for OS in the multivariate analysis using the Cox proportional hazards model.

CONCLUSION

The efficacy of each first-line chemotherapy regimen for advanced thymic carcinoma did not vary significantly. Our results might support the adequacy of the use of carboplatin/paclitaxel as first-line chemotherapy for these patients.

IMPLICATIONS FOR PRACTICE

Because of its rarity, there is limited information about prognostic factors and efficacy of chemotherapy in patients with advanced thymic carcinoma. This is the largest data set for those patients treated with chemotherapy. This study suggests there is no significant difference in efficacy between carboplatin/paclitaxel and cisplatin/doxorubicin/vincristine/cyclophosphamide for advanced thymic carcinoma. This result can support the adequacy of the selection of platinum doublets as treatment for those patients, rather than anthracycline-based multidrug regimen.

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

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

Expression of excision repair cross-complementation group 1 and class III β-tubulin in thymic carcinoma

Thymic carcinoma is a rare mediastinum malignant tumor derived from thymic epithelial cells. With the exception of complete resection, an effective therapy has not been established to date for advanced or relapsed thymic carcinoma. The present study examined the protein expression of excision repair cross-complementation group 1 (ERCC1) and class III β-tubulin (TUBB3), which are consider to be indicators of the anticancer activity of platinum-based and taxane-based chemotherapy, respectively. The expression of ERCC1 and TUBB3 proteins was examined in 40 thymic carcinoma patients who underwent either surgical resection or core-needle biopsy. The present study investigated whether the expression of ERCC1 and TUBB3 proteins was associated with the overall survival and clinicopathological factors of thymic carcinoma patients. The expression of ERCC1 and TUBB3 proteins was also evaluated in 50 patients who underwent curative resection for non-small cell lung cancer (NSCLC). The expression of ERCC1 and TUBB3 proteins was positive in 8 cases (20%) among the thymic carcinoma patients. ERCC1 was expressed in 21 cases (42%), while TUBB3 was expressed in 27 cases (54%), among the 50 NSCLC patients evaluated in the present study. Only complete resection was observed to be associated with a better prognosis than incomplete resection (P=0.0341). Other clinicopathological factors, including expression of ERCC1 and TUBB3 proteins, exhibited no effect on overall survival. The expression of ERCC1 and TUBB3 proteins in the thymic carcinoma cases was lower than that in the NSCLC cases. The present results suggest a possibility for better antitumor effects of platinum-based and taxane-based chemotherapy on thymic carcinoma patients.

Identification of prognostic and subtype-specific potential miRNAs in thymoma

AIM

We performed a study to identify the role of microRNA in thymoma.

PATIENTS & METHODS

One hundred twenty-three thymoma patients with clinical information and miRNA expression data from The Cancer Genome Atlas were included in the study. Comprehensive bioinformatics analysis was integrated in our analysis.

RESULTS & CONCLUSION

Seven miRNAs were found to be associated with overall survival (p < 0.001). Another four miRNAs were found to be associated with disease-free survival (p < 0.001). Type C thymoma can be distinguished from nontype C thymoma by miRNAs. Interestingly, seven miRNAs showed both prognostic and subtype-specific potential. Our findings suggest that miRNAs can be used for prognostic prediction and subtype stratification.

Chemotherapy with gemcitabine plus cisplatin in patients with advanced thymic squamous cell carcinoma: Evaluation of efficacy and toxicity

Background

Squamous cell carcinoma of the thymus is a rare thymic epithelial neoplasm that tends to widely metastasize at initial presentation. Because of its rarity, the optimal chemotherapeutic regimen remains uncertain. A gemcitabine and cisplatin regimen has shown promising efficacy in the treatment of other squamous cell carcinomas. We assessed the efficacy and toxicity of this regimen in patients with advanced thymic squamous cell carcinoma.

Methods

Between January 2003 and December 2012, 13 patients with untreated or unresectable recurrent thymic squamous cell carcinomas, who were treated with gemcitabine and cisplatin, were retrospectively analyzed. The endpoints in this study were clinical response rate, disease control rate, progression‐free survival, and overall survival. Significant hematological and non‐hematological toxicities were also assessed.

Results

Three patients were in Masaoka stage IVa and 10 were in stage IVb. The median number of treatment cycles for the present chemotherapy regimen was four. The clinical response and disease control rates were 61.5% and 92.3%, respectively. The median progression‐free and median overall survival rates were 14.5 months (95% confidence interval, 9.2–19.8 months) and 50.7 months (95% confidence interval, 24.9–76.5 months), respectively. Grade 3/4 hematological toxicities were observed in seven (53.8%) patients, and non‐hematological toxicities were mild.

Conclusion

This retrospective analysis demonstrated that gemcitabine plus cisplatin was active against advanced thymic squamous cell carcinoma with manageable toxicity. Gemcitabine may be a novel and alternative agent for advanced thymic squamous cell carcinoma.

Available evidence and new biological perspectives on medical treatment of advanced thymic epithelial tumors

Thymic epithelial tumors (TETs) are rare primary mediastinal tumors arising from thymic epithelium. Their rarity and complexity hinder investigations of their causes and therapy development. Here, we summarize the existing knowledge regarding medical treatment of these tumors, and thoroughly review the known genetic aberrations associated with TETs and the present status of potential biological treatments. Epidermal growth factor receptor (EGFR), stem-cell factor receptor, insulin-like growth factor-1 receptor (IGF1R), and vascular endothelial growth factors (VEGF-A, VEGF-B, and VEGF-2) are overexpressed in TETs. EGFR overexpression in TETs is associated with higher stage, and IGF1R overexpression has poor prognostic value. Data indicate that anti-IGF1R monoclonal antibodies, and inhibitors of angiogenesis, somatostatin receptors, histone deacetylase, mammalian target of rapamycin, and cyclin-dependent kinases may be active against TETs. Continued investigations in this field could lead to advancement of targeted and biological therapies for TETs.

A multicenter phase II study of carboplatin and paclitaxel for advanced thymic carcinoma: WJOG4207L

BACKGROUND

Thymic carcinoma (TC) is an exceptionally rare tumor, which has a very poor prognosis differing from thymoma. Till date, there has been no report of any results of clinical trials focusing on TC. The role of non-anthracycline-based chemotherapy has not been elucidated since the previous studies included a relatively small number of TC patients. This single-arm study evaluated carboplatin and paclitaxel (CbP) in chemotherapy-naive patients with advanced TC.

PATIENTS AND METHODS

The study treatment consisted of carboplatin (area under the curve 6) and paclitaxel (200 mg/m(2)) every 3 weeks for a maximum of six cycles. The primary end point was objective response rate (ORR) by independent review. The secondary end points included overall survival (OS), progression-free survival (PFS), and safety. Based on the SWOG 2-stage design, the planned sample size of 40 patients was determined to reject the ORR of 20% under the expectation of 40% with a power of 0.85 and a type I error of 0.05.

RESULTS

Forty patients from 21 centers were enrolled for this study from May 2008 to November 2010. Of the 39 patients evaluable for analysis, 36 were pathologically diagnosed by independent review, and 97% patients were eventually TC. There was 1/13 complete/partial responses with an ORR of 36% (95% confidence interval 21%-53%; P = 0.031). The median PFS was 7.5 (6.2-12.3) months, while OS did not reach the median value. Major adverse event was grade 3-4 neutropenia in 34 patients (87%). There was no treatment-related death.

CONCLUSIONS

In this largest trial with TC, CbP showed promising efficacy in advanced TC when compared with anthracycline-based chemotherapy, which is the current standard treatment of thymic neoplasm. Our results established that CbP, one of the standard treatments for non-small-cell lung cancer, might be an option as a chemotherapy regimen for TC.

Metronomic maintenance chemotherapy in patients presenting with paraneoplastic autoimmune hepatitis with recurrent thymic carcinoma

Autoimmune hepatitis is a rarely seen autoimmune paraneoplastic syndrome of thymic carcinoma. Chemotherapy may be an effective choice in the treatment of primary tumor and paraneoplastic disorder. In this case, we report a 32-year-old man presented with increased liver enzymes and cholestasis with a history of thymoma surgically removed four years ago. Liver biopsy showed chronic active autoimmune hepatitis. Computed tomography scan showed pulmonary metastases and pleural mass as a recurrence of thymic carcinoma, proven by biopsy. After four cycles of cisplatin plus adriamycin plus cyclophosphamide plus vincristine and six cycles of paclitaxel plus gemcitabine, maintenance metronomic cyclophosphamide plus etoposide regimen was offered to the patient. Complete biological signs of hepatitis without need for steroids or immune suppressors and complete radiologic response in primary tumor were achieved. Maintenance metronomic chemotherapy regimens may be an alternative to the current treatment options in patients with thymic carcinomas.

Key components of chemotherapy for thymic malignancies: a systematic review and pooled analysis for anthracycline-, carboplatin- or cisplatin-based chemotherapy

Purpose

Thymic malignancies, comprising thymoma and thymic carcinoma, are rare. Consequently, optimal chemotherapy for advanced thymic malignancies remains controversial. Platinum-based chemotherapy is currently the consensus treatment based on the results of single-arm phase II trials and retrospective investigations. However, comparison of cisplatin-based and carboplatin-based chemotherapy has yet to be undertaken; the effectiveness of the addition of anthracycline also remains uncertain.

Methods

In the present study, clinical trials and retrospective data regarding platinum-based chemotherapy were analyzed. The endpoint was the response rate to each chemotherapy. For advanced thymoma, we compared platinum with anthracycline-based chemotherapy and platinum with non-anthracycline-based chemotherapy. For advanced thymic carcinoma, anthracycline-based versus non-anthracycline-based chemotherapy and carboplatin-based versus cisplatin-based chemotherapy were compared. This analysis included a retrospective study of response of advanced thymic carcinoma to irinotecan and cisplatin in our institution.

Results

The response rate for the 314 patients from 15 studies with advanced thymoma, including both prospective and retrospective data, was 69.4 % [95 % confidence interval (CI) 63.1–75.0 %] for platinum with anthracycline-based chemotherapy and 37.8 % (95 % CI 28.1–48.6 %; p < 0.0001) for platinum with non-anthracycline-based chemotherapy. The response rates after anthracycline-based and non-anthracycline-based chemotherapy for advanced thymic carcinoma were similar (41.8 vs. 40.9 %; p < 0.91), whereas the response rates after cisplatin-based and carboplatin-based chemotherapy for advanced thymic carcinoma differed significantly (53.6 vs. 32.8 %; p = 0.0029) in 206 patients from 10 studies.

Conclusions

Platinum with anthracycline-based chemotherapy is an optimal combination for advanced thymoma. For advanced thymic carcinoma, cisplatin-based chemotherapy may be superior to carboplatin-based chemotherapy.

nab-Paclitaxel in Combination with Carboplatin for a Previously Treated Thymic Carcinoma

We present the case of a 40-year-old man with previously treated thymic carcinoma, complaining of gradually worsening back pain. Computed tomography scans of the chest showed multiple pleural disseminated nodules with a pleural effusion in the right thorax. The patient was treated with carboplatin on day 1 plus nab-paclitaxel on day 1 and 8 in cycles repeated every 4 weeks. Objective tumor shrinkage was observed after 4 cycles of this regimen. In addition, the elevated serum cytokeratin 19 fragment level decreased, and the patient's back pain was relieved without any analgesics. Although he experienced grade 4 neutropenia and granulocyte colony-stimulating factor (G-CSF) injection, the severity of thrombocytopenia and nonhematological toxicities such as reversible neuropathy did not exceed grade 1 during the treatment. To our knowledge, this is the first report to demonstrate the efficacy of combination chemotherapy consisting of carboplatin and nab-paclitaxel against thymic carcinoma. This case report suggests that nab-paclitaxel in combination with carboplatin can be a favorable chemotherapy regimen for advanced thymic carcinoma.

Thymic neoplasms: an update on the use of chemotherapy and new targeted therapies. A literature review

Thymic malignancies represent a wide range of clinical, histological and molecular entities, with probably considerable heterogeneity even among tumors of the same histotype. Systemic chemotherapy with cisplatin-based regimens continues to represent the standard of care in metastatic or inoperable refractory/recurrent diseases and ADOC regimen (including cisplatin, doxorubicin, vincristine and cyclophosphamide) demonstrated the longer overall response rate and median survival in the first line setting, although no randomized trial is available; and there is still a lack of standard treatment after first-line failure. To date research efforts are focused on translational studies on molecular pathways involved in thymic tumors carcinogenesis, aimed to better understand and predict the efficacy of chemotherapy and targeted therapy. Recent molecular characterization includes identification of a number of oncogenes, tumor suppressor genes, chromosomal aberrations, angiogenic factors, and tumor invasion factors involved in cellular survival and proliferation and in tumor growth. The use of biologic drugs is currently not recommended in a routine practice because there are limited data on their therapeutic role in thymic epitelial tumors. Because of the lack of data from adequate-sized, prospective trials are required for validation and the enrolment of patients with advanced disease into available clinical trials has to be encouraged.

Thymic neoplasm: a rare disease with a complex clinical presentation

Thymic neoplasms constitute a broad category of rare lesions with a wide spectrum of pathologic characteristics and clinical presentations which therefore require a high index of suspicion to diagnose. The natural history of the disease is seldom predictable, anywhere from an indolent to an aggressively malignant course. Although the classification and staging of these lesions are complex and controversial, complete radical surgical resection remains the gold standard of therapy. Radiation and chemotherapy are important elements of the multimodality approach to treating these patients and it is important for thoracic surgeons to work closely with their colleagues in other disciplines in the management of and future research endeavors in thymic neoplasm. In this review, we discuss the evaluation of the patient with an anterior mediastinal mass, the classification and staging of thymic neoplasms, the role of surgery, radiation and chemotherapy in treating this disease, as well as future directions in research for novel targeted therapies.

Messenger RNA and protein expression of thymidylate synthase and DNA repair genes in thymic tumors

BACKGROUND

Thymic epithelial tumors include several entities with different biologic behavior. Chemotherapy is indicated in advanced disease, but limited data exist on gene expression correlation with the response to chemotherapeutic agents.

PATIENTS AND METHODS

A series of 69 thymic neoplasms (7 A-, 6 AB-, 6 B1-, 10 B2-, 14 B3-thymomas, 22 carcinomas and 4 combined tumors) was collected to assess gene expression of thymidylate synthase (TS), excision repair cross complementing-1 (ERCC1), ribonucleotide reductase subunit 1 (RRM1), topoisomerase 2α (TOP2A) and mTOR.

RESULTS

A strong linear correlation between TS gene and protein expression was observed (P<0.0001, R=0.40). TS expression was significantly lower in pure A-thymomas and thymic carcinomas (P<0.0001) and progressively decreasing from B1-type to thymic carcinomas (B1>B2>B3>C; P<0.0001). RRM1 and TOP2A mRNA expression levels were significantly correlated with TS levels (both P=0.03) with a similar trend of expression among histotypes. RRM1 and TOP2A high levels were significantly correlated with high TS (P=0.03) and low tumor stages (I-II) (P<0.0001 and P<0.01, respectively). No relevant changes of ERCC1 and mTOR were detected.

CONCLUSIONS

Low TS and, to a minor extent, RRM1 and TOP2A expression were detected in aggressive thymic tumors. These findings should be prospectively considered in selecting the most appropriate chemotherapy.

Long-survival case of thymic carcinoma with superior vena cava tumor thrombus

Sarcomatoid carcinoma of the thymus is rare and responds poorly to treatment. Invasion of great vessels and metastasis are significant predictors for poor prognosis. Thymic tumors commonly cause superior vena cava (SVC) obstruction by extrinsic compression or invasion, but intraluminal permeation is the most uncommon cause. We report a rare, long-surviving case of sarcomatoid carcinoma with SVC syndrome developed by tumor thrombus. She underwent SVC replacement and extended thymectomy. The resection indicated intracaval extension without direct invasion of thymic tumor, histologically diagnosed as sarcomatoid carcinoma. After adjuvant chemotherapy, she continues to show no apparent recurrence for five years.

Emerging treatment options for patients with recurrent advanced thymic epithelial tumors

The purpose of this review article is to review recent advances in the treatment of advanced thymic epithelial tumors. These tumors are generally responsive to cytotoxic combination chemotherapy in the first-line setting. While newer agents have shown efficacy in the salvage setting, there is no one standard approach. A multitude of targeted agents have shown promise generally in case reports, though as of yet, nothing has shown consistent benefit. Because of the rarity of thymic epithelial tumors, clinical trial enrollment is difficult but nevertheless essential.