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

A Re-Examination of Neoadjuvant Therapy for Thymic Tumors: A Long and Winding Road

For most patients with advanced thymic epithelial tumors (TETs), a complete resection is a strong indicator of a better prognosis. But sometimes, primary surgery is unsatisfactory, and preoperative therapy is needed to facilitate complete resection. Neoadjuvant chemotherapy is the most used form of preoperative therapy. But studies on neoadjuvant chemotherapy have included mainly patients with thymoma; its efficacy in patients with thymic carcinoma is less known. Neoadjuvant chemoradiation has also been explored in a few studies. Novel therapies such as immunotherapy and targeted therapy have shown efficacy in patients with recurrent/metastatic TETs as a second-line option; their role as preoperative therapy is still under investigation. In this review, we discuss the existing evidence on preoperative therapy and the insight it provides for current clinical practice and future studies.

Surgical treatment of thymic epithelial tumors: a narrative review

Background and Objective

Thymic epithelial tumors (TETs) are scarce neoplasms of the prevascular mediastinum. Included in this diverse category of lesions are thymomas and thymic carcinomas (TCs). Surgery is the mainstay of treatment of tumors that are deemed resectable. However, up till now, optimal surgical access has been a subject of debate. The advent of new techniques, such as video-assisted thoracoscopic surgery (VATS) and robotic-assisted thoracoscopic surgery (RATS), challenged the median sternotomy which was traditionally considered the access of choice. This review aims to demonstrate the current evidence concerning the surgical treatment of TET and to enlighten other controversial issues about surgery.

Methods

PubMed research was conducted using the terms [surgery] AND [thymic epithelial tumors] OR [thymomas] and [surgical treatment] AND [thymic epithelial tumors] OR [thymomas]. Papers concerning pediatric cases and non-English literature papers were excluded. Individual case reports were also excluded.

Key Content and Findings

Minimally invasive surgical techniques (MIST) such as VATS and RATS are increasingly applied in early-stage TET. Although numerous published studies have demonstrated better perioperative outcomes in early-stage TET, long-term follow-up data are still required to demonstrate the oncological equivalent of MIST to open surgery. Resection of stage III TET is more challenging. Thymectomy can be expanded en bloc to include the major vascular structures, lung, pleura, phrenic, or vagus nerve in these individuals. There is no agreement on the ideal surgical access and traditionally these patients underwent open sternotomy, sometimes combined with a thoracic access. Evidence concerning the treatment of stage IVA disease is mainly derived from retrospective case series which are highly heterogeneous in terms of the number of enrolled patients, histology, degree of pleural involvement, and timing of presentation.

Conclusions

New techniques in the field of minimally invasive surgery are gaining acceptance for early-stage TET but longer follow-up periods are warranted to prove their oncological outcomes. On the contrary, these techniques should be used cautiously in case of locally advanced tumors. Surgeons must not forget that the main objective is the complete resection of the lesion, which is one major predictive factor for increased survival.

Immunotherapy and Targeted Therapies Efficacy in Thymic Epithelial Tumors: A Systematic Review

BACKGROUND

Thymic epithelial tumors (TET) are rare neoplasms of the anterior mediastinum. Surgery is the mainstay treatment for resectable TET, whereas systemic treatments are reserved for unresectable and metastatic tumors. The development of new treatments, such as immune checkpoint inhibitors (ICI) and targeted therapies, with promising results in other types of solid tumors, has led to the investigation of their potential efficacy in TET. The study of tumor microenvironments (TME) is another field of investigation that has gained the interest of researchers. Taking into account the complex structure of the thymus and its function in the development of immunity, researchers have focused on TME elements that could predict ICI efficacy.

MATERIALS AND METHODS

The primary objective of this systematic review was to investigate the efficacy of ICI in TET. Secondary objectives included the toxicity of ICI, the efficacy of targeted therapies in TET, and the evaluation of the elements of TME that may be predictive factors of ICI efficacy. A literature search was conducted in February 2023 using the Ovid Medline and SciVerse Scopus databases.

RESULTS

2944 abstracts were retrieved, of which 31 were retained for the systematic review. Five phase II and one retrospective study assessed ICI efficacy. The overall response rate (ORR) varied from 0% to 34%. Median progression-free survival (PFS) ranged from 3.8 to 8.6 months, being lower in thymic carcinoma (TC) (3.8-4.2 months). Median overall survival (OS) ranged from 14.1 to 35.4 months. Treatment-related adverse events occurred in 6.6% to 27.3% of patients. Sixteen studies assessed targeted therapies. The most active molecule was lenvatinib, with 38% ORR in patients with TC while no activity was detected for imatinib, erlotinib plus bevacizumab, and saracatinib. Ten studies assessed TME elements that could predict ICI efficacy. Four studies focused on the tumor-infiltrating immune cells suggesting improved outcomes in patients with TC and high tumor-infiltrating lymphocyte densities. Another study showed that CD8+, CD20+, and CD204+ tumor-infiltrating immune cells in cancer stroma might be prognostic biomarkers in TC. Another study identified the immune-related long non-coding RNAs as a predictor of response to ICI. Tumor mutational burden was identified as a predictive factor of ICI efficacy in one study.

CONCLUSIONS

Despite study heterogeneity, this review shows that ICI could be a therapeutic option for selected patients with TET that are not amenable to curative radical treatment after first-line chemotherapy.

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.

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.

Efficacy and safety of treatments for advanced thymic carcinoma after failure of first-line platinum-based chemotherapy: A systematic literature review and meta-analysis

Thymic carcinoma (TC) is a rare cancer and patients failing initial chemotherapy (relapse/refractory) face limited therapeutic options given no approved options or consensus standard of care. This study aimed to identify and summarize clinical outcomes of all regimens evaluated in clinical trials of relapsed or refractory patients. Interventional trials enrolling advanced TC patients who failed first-line chemotherapy and reported outcomes in this group were eligible for inclusion in our systemic literature review (SLR). Between-study heterogeneity was assessed to determine the feasibility of pooling specific studies and treatments. Objective response rate (ORR), overall survival (OS), progression-free survival (PFS), and duration of response (DOR) endpoints were of interest for meta-analysis. Nineteen trials were identified in the SLR. Three trials with one or two TC patients were removed from our assessment to reduce publication bias. Response rates among studies with at least ten TC patients varied from 9 % to 38 %. Pooled ORRs in patients receiving S-1 (46 patients), sunitinib (46 patients), or pembrolizumab (66 patients) were 28 %, 24 %, and 21 %, respectively. Prolonged duration of response with pembrolizumab was observed with a pooled median of 23.8 months (95 % confidence interval [CI]: 12, not reached). Median PFS of five months or greater was reported in patients treated with sunitinib, lenvatinib, pembrolizumab, capecitabine + gemcitabine, everolimus, or S-1. Median OS of 20 months or greater was reported in trials evaluating S-1 or pembrolizumab; this endpoint was not reached in trials evaluating lenvatinib, regorafenib, or sunitinib. Generalizability of treatment effects is challenging in the research of rare diseases and meta-analysis of clinical outcomes may help to increase precision and relevance of results to the larger TC population. Our study found limited treatment options upon relapse, demonstrating a need for further investigations into novel therapeutics and well-powered clinical trials to better inform on optimal treatments.

Prognostic factors and genetic markers in thymic epithelial tumors: A narrative review

Thymic epithelial tumors (TET) are a group of rare neoplasms of the anterior mediastinum comprising thymomas and thymic carcinomas. The carcinogenesis of TET is mostly unknown. Many studies, mostly retrospective case series, have tried to establish prognostic factors in TET. TET is a very heterogeneous group of tumors with many subtypes for which diagnosis and treatment remains a very challenging task. Despite the disparities among retrospective studies, there are some prognostic factors that are more pertinent such as the completeness of resection, TNM stage and the Masaoka-Koga classification. On the other hand, the identification of different genetic pathways that result in the pathogenesis of TET represents a fascinating field of study that could possibly lead to the development of new targeted therapies. The aim of this review is to discuss the different prognostic factors and genetic markers of TET. The meticulous use of national and international databases could provide sufficient number of patients in order to draw more valid conclusions.

Thymic Carcinomas-A Concise Multidisciplinary Update on Recent Developments From the Thymic Carcinoma Working Group of the International Thymic Malignancy Interest Group

Thymic carcinomas are rare malignancies that in general arise in the prevascular (anterior) mediastinum. These tumors are usually invasive, often present at advanced stages, and typically behave aggressively. Studies are hampered by the paucity of these tumors, the large variety of carcinoma subtypes, and the lack of unique morphologic and immunophenotypic features. Despite these challenges, advances in diagnostic imaging, surgical approaches, systemic therapies, and radiation therapy techniques have been made. The WHO classification of thymic epithelial tumors has been updated in 2021, and the eighth tumor nodal metastasis staging by the American Joint Committee on Cancer/Union for International Cancer Control included thymic carcinomas in 2017. Molecular alterations that provide more insight into the pathogenesis of these tumors and that potentially permit use of novel targeted therapies are increasingly being identified. New approaches to radiation therapy, chemotherapy, and immunotherapy are under evaluation. International societies, including the International Thymic Malignancy Interest Group, European Society of Thoracic Surgeons, and Japanese, Chinese, and Korean thymic associations, have been critical in organizing and conducting multi-institutional clinical studies. Herein, we review contemporary multidisciplinary perspectives in diagnosis and management of thymic carcinoma.

Therapeutic options in thymomas and thymic carcinomas

INTRODUCTION

Radical surgery is the best therapeutic option for thymic malignancies. However, patients with advanced or recurrent thymic malignancies often require chemotherapy or radiotherapy. Since thymic malignancies are rare cancers, the efficacy and safety of treatments have been verified based on small Phase 2 trials or retrospective studies.

AREA COVERED

We comprehensively reviewed the treatment strategies for thymic malignancies, including surgery, radiotherapy, and pharmacotherapy, including cytotoxic chemotherapy, molecular-targeted therapy, and immunotherapy. Additionally, we reviewed specific situations, such as pleural dissemination, central nervous system metastasis, and paraneoplastic syndrome.

EXPERT OPINION

Cytotoxic chemotherapy remains the standard option in pharmacotherapy. However, multikinase inhibitors, such as sunitinib and lenvatinib, and immune checkpoint inhibitors including pembrolizumab have been developed to treat thymic carcinomas. Now, a Phase 2 study is evaluating whether lenvatinib plus pembrolizumab benefits patients with type B3 thymoma or thymic carcinoma. Phosphatidylinositol 3-kinase/AKT/ mammalian target of rapamycin inhibitors may contribute to disease control and octreotide scan is only applicable to somatostatin analogues. Although the genomic characteristics of thymic malignancies have been analyzed, few actionable mutations have been detected in general. The development of a treatment strategy using combination pharmacotherapy is anticipated.

Association of lung immune prognostic index with survival outcome in advanced thymic carcinoma patients treated with palliative intent chemotherapy

Background

Methods

Results

Conclusions

Clinical Significance of Tumor Markers for Advanced Thymic Carcinoma: A Retrospective Analysis from the NEJ023 Study

Simple Summary

Advanced thymic carcinoma (ATC) is rare. Owing to its rarity, there is limited information on the prognostic factors, and the optimal serum tumor markers are also unknown. We conducted a multi-institutional retrospective study of patients with ATC. In this study, we collected data on patient characteristics, progression-free survival (PFS), overall survival (OS), and tumor marker values, and investigated the relationship between tumor marker values and PFS/OS. We found that the neuron-specific enolase (NSE) level may be a useful prognostic tumor marker for ATC, regardless of histology. The findings of the analysis limited to squamous cell carcinoma suggested that the NSE and squamous cell carcinoma antigen levels may be useful prognostic factors.

Abstract

The optimal tumor marker for predicting the prognosis of advanced thymic carcinoma (ATC) remains unclear. We conducted a multi-institutional retrospective study of patients with ATC. A total of 286 patients were treated with chemotherapy. Clinicopathological information, including serum tumor markers, was evaluated to determine the overall survival (OS) and progression-free survival (PFS). The carcinoembryonic antigen, cytokeratin-19 fragment, squamous cell carcinoma (SCC) antigen, progastrin-releasing peptide, neuron-specific enolase (NSE), and alpha-fetoprotein levels were evaluated. In the Kaplan–Meier analysis, the OS was significantly shorter in the patients with elevated NSE levels than in those with normal NSE levels (median, 20.3 vs. 36.8 months; log-rank test p = 0.029; hazard ratio (HR), 1.55; 95% confidence interval (CI), 1.05–2.31 (Cox proportional hazard model)); a similar tendency regarding the PFS was observed (median, 6.4 vs. 11.0 months; log-rank test p = 0.001; HR, 2.04; 95% CI, 1.31–3.18). No significant differences in the OS and PFS were observed among the other tumor markers. In both univariate and multivariate analyses of the patients with SCC only, the NSE level was associated with the OS and PFS. Thus, the NSE level may be a prognostic tumor marker for thymic carcinoma, regardless of histology.

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.

Debulking surgery for malignant tumors: the current status, evidence and future perspectives

Debulking surgery, also called cytoreductive surgery, is a resection of the tumor as much as possible and an intended incomplete resection for unresectable malignant tumors. Since the most important principle in surgical oncology is complete R0 resection, debulking surgery goes against the basic principle and obscures the concept of operability. However, debulking surgery has been advocated for various types of advanced malignant tumors, including gynecological cancers, urological cancers, gastrointestinal cancers, breast cancers and other malignancies, with or without adjuvant therapy. Positive data from randomized trials have been shown in subsets of ovarian cancer, renal cell carcinoma, colorectal cancer and breast cancer. However, recent trials for renal cell carcinoma, colorectal cancer and breast cancer have tended to show controversial results, mainly according to the survival improvement of nonsurgical systemic therapy alone. On the other hand, debulking surgery still has a therapeutic role for slow-growing and borderline malignant tumors, such as pseudomyxoma peritonei and thymomas. The recent understanding of tumor heterogeneity and clonal evolution responsible for malignancy and drug resistance indicates that select patients may obtain prolonged survival by the synergistic effect of debulking surgery and novel systemic therapy. This review aimed to describe the current status and evidence of debulking surgery in a cross-organ manner and to discuss future perspectives in the current era with advances in systemic therapy.

Multi-institutional survey of thymic carcinoma patients in Hokushin region

BACKGROUND

Thymic carcinoma is a rare neoplasm, and its prognosis is very poor. The purpose of this study was to validate the clinical and epidemiological factors, diagnosis and initial treatment of thymic carcinoma among all patients diagnosed in the registered hospital group.

METHODS

We surveyed retrospective data from 152,921 cancer patients in 22 principal hospitals.

RESULTS

A total of 88 thymic carcinoma cases were newly diagnosed. These patients were 50 men and 38 women, with a median age of 66 years old. Eight patients were discovered in cancer screening, 9 in a voluntary setting, 14 at health checkups, 25 at follow-up of other diseases, and 32 cases by introduction from another hospital. Only 14 cases had been diagnosed with localized disease, but 5 cases were accompanied by regional lymph node metastasis. Furthermore, 12 cases showed infiltration into adjacent organs, and 24 cases had distant metastasis. Eighty-three cases were diagnosed by a pathological diagnosis. A surgical approach, chemotherapy, and radiotherapy were performed for 29, 35 patients, and 31 patients, respectively, while 17 patients received best supportive care.

CONCLUSION

The diagnosis of thymic carcinoma is still difficult, and this disease has a tragically rapid progression if when discovered during follow-up of other diseases. An innovative modality for the early detection of thymic carcinoma is needed in modern medical society.

Direct Intraesophageal Growth from Metastatic Mediastinal Lymphadenopathy in Thymic Carcinoma

We herein report a case of thymic carcinoma that initially exhibited dysphagia and an intraesophageal mass lesion. A 68-year-old man was admitted to our hospital because of dysphagia. An endoscopic examination revealed a mass on the middle esophagus. Chest computed tomography (CT) showed a huge anterior mediastinal mass and subcarinal lymph node swelling, directly invading into the esophageal lumen. An immunohistological examination of the esophageal and anterior mediastinal masses revealed squamous cell carcinoma originating from the thymus. This is the first report of a thymic carcinoma spreading into the esophageal lumen and forming a mass lesion.

Prognostic factors for patients with metastatic or recurrent thymic carcinoma receiving palliative-intent chemotherapy

BACKGROUND

Thymic malignancies are a model of rare cancer. However, little clinical data is available based on the large database. We aimed to clarify the prognostic factors, particularly the metastatic sites, for thymic malignancies using one of the largest, representative, multi-institutional databases, the NEJ023 database.

PATIENTS AND METHODS

Patients with Stage IVA/IVB or recurrent thymic carcinoma were enrolled between 1995 and 2014. Clinicopathologic information was evaluated, and the patients were subdivided according to the metastatic organs of involvement (serosal dissemination, liver, lymph node, pulmonary, and bone metastasis). A Kaplan-Meier analysis and multivariate Cox regression were used to evaluate survival.

RESULTS

Two hundred and seventy-nine patients with metastases and a predominantly squamous histology (66.7%) were included. Most patients (53.0%) had serosal dissemination, whereas 26.5%, 21.9%, 19.7%, and 15.8% had pulmonary, lymph node, bone and liver metastases, respectively. Over a median follow-up time of 21.5 months, the median overall survival (mOS) was 30.7 months. When the subjects were grouped according to involved metastatic sites, patients with more than 3 involved metastatic organs had the worst survival outcome. Among patients with isolated involvement, those with bone metastasis had the poorest survival, followed by patients with liver metastasis. Subjects with hypoalbuminemia also had poor survival outcomes. When patients treated with platinum and anthracycline-containing pharmacotherapy were compared with those treated with platinum and non-anthracycline-containing pharmacotherapy, no significant difference was observed. Bone metastasis (P = 0.0005), liver metastasis (P =  0.047), and hypoalbuminemia (P =  0.0021) were identified as prognostic factors in a multivariate analysis.

CONCLUSION

The site of metastatic involvement affects the survival outcomes of patients with thymic carcinoma, and this result may reflect the sensitivity of metastatic sites to pharmacotherapy. As a next step, controlling liver metastasis with pharmacotherapy could help to improve the prognosis of patients with thymic carcinoma.

National incidence and initial therapy for thymic carcinoma in Japan: based on analysis of hospital-based cancer registry data, 2009-2015

BACKGROUND

Although thymic carcinoma is a rare epithelial neoplasm that tends to be aggressive and metastasize widely, its incidence in Japan remains unclear. This study was to examine the incidence and initial treatment of thymic carcinoma in the Japanese population using data from a hospital-based cancer registry.

METHODS

Using data from the national database of hospital-based cancer registries, we examined the incidence and initial treatment of thymic carcinoma diagnosed and treated in designated and non-designated cancer care hospitals between 2009 and 2015. Based on Japanese population estimates, we calculated the incidence rate of thymic cancer in Japan.

RESULTS

A total of 2587 thymic carcinoma cases were diagnosed between 1 January 2009 and 31 December 2015. These patients consisted of 1705 (66%) men and 882 (34%) women, with a median age of 65.5 years (range, 16-96 years). The number and proportion of thymic carcinoma to all registered cancer cases per year increased each year. The incidence rate was estimated to be 0.29/100000 during the observation period, with an annual onset incidence of 0.38/100000 in 2015. Almost half of all cases of thymic carcinoma were treated surgically, while the others were treated with non-surgical therapy consisting of chemotherapy with or without radiotherapy.

CONCLUSIONS

We estimated the incidence rate of thymic carcinoma in Japan based on the designated cancer care hospital-based cancer registry. The half of all patients with thymic carcinoma was unfit for multimodality therapy, including thoracic surgery.

Clinical Outcomes of Second-Line Chemotherapy in Patients with Previously Treated Advanced Thymic Carcinoma: A Retrospective Analysis of 191 Patients from the NEJ023 Study

BACKGROUND

Owing to the rarity of this tumor, there is limited information about second-line chemotherapy for patients with previously treated advanced thymic carcinoma.

MATERIAL AND METHODS

We performed a multi-institutional, retrospective study named NEJ023 for patients with advanced thymic carcinoma. Patients without indications for curative treatment were treated with chemotherapy from 1995 to 2014 at 40 institutions in the North East Japan Study Group. Demographic and clinicopathologic characteristics, data on treatment methods, and outcomes of second-line chemotherapy were obtained from medical records.

RESULTS

In total, 191 patients were enrolled in this study. Second-line chemotherapy included platinum-based doublets in 57.6% of patients, other multidrug chemotherapy (e.g., cisplatin, doxorubicin, vincristine, and cyclophosphamide) in 13.6%, and monotherapy in 28.8%. The median follow-up time was 50.5 months, and the median overall survival (OS) from the start of second-line chemotherapy was 22.4 (95% confidence interval, 17.5-26.7) months. The average response rate (RR) was 20.0% overall; it was 21.6% for patients treated with platinum-based doublet chemotherapy, 13.6% for those treated with other multidrug chemotherapy, and 19.6% for those treated with single agent chemotherapy. There was no significant difference in OS between platinum-based doublet chemotherapy, other multidrug chemotherapy, and monotherapy (the median OS was 22.4, 25.7, and 21.4 months, respectively).

CONCLUSION

The median OS was 22.4 months in patients with advanced thymic carcinoma treated with second-line chemotherapy. There were no significant differences in RR and OS between monotherapy and multidrug chemotherapy in this study.

IMPLICATIONS FOR PRACTICE

Owing to the rarity of this tumor, there is limited information about second-line chemotherapy for patients with previously treated advanced thymic carcinoma. This is the largest data for those patients treated with second-line chemotherapy. This study suggests there is no significant difference in efficacy between monotherapy and multidrug chemotherapy for previously treated advanced thymic carcinoma. This result can support the adequacy to select monotherapy as treatment of those patients.