Thoracic mesenchymal malignant tumors and programed cell death ligand-1 status: Clinicopathologic and prognostic analysis of eight pulmonary sarcomatoid carcinomas and eight malignant mesotheliomas

Our plain-English summary of Thoracic mesenchymal malignant tumors and programed cell death ligand-1 status: Clinicopathologic and prognostic analysis of eight pulmonary sarcomatoid carcinomas and eight malignant mesotheliomas, by K. Otsubo, H. Sakai, H. Kimura, et al (Thoracic Cancer, 2021).

The study

• Authors: K. Otsubo, H. Sakai, H. Kimura, T. Miyazawa, H. Marushima, K. Kojima, N. Furuya, M. Mineshita, M. Chosokabe, J. Koike, H. Saji
• Journal: Thoracic Cancer
• Published: 2021;12(23):3169-3176
• Cited by: 1 article, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Background: The current study aimed to evaluate the significance of clinicopathological factors, particularly the immunohistochemistry of programed cell death ligand-1 (PD-L1), in eight cases each of pulmonary sarcomatoid carcinoma (PSC) and malignant pleural mesothelioma (MPM) at our hospital.

Methods: From January 2004 to December 2020, a total of 16 consecutive patients (eight with PSC and eight with MPM diagnosed via surgical resection or biopsy) were included in this study. After retrospectively reviewing the patient characteristics, the associations between PD-L1 status and age, sex, stage, histological type, and prognosis were investigated.

Results: PD-L1-positive staining was observed in four (50%) PSC cases and one (12.5%) MPM case. Among the four PD-L1-positive PSC cases, two showed high PD-L1 expression in the vimentin-positive sarcomatoid compartment. Moreover, among those with PSC, two survived for about 10 years, whereas the others died within 5 years. No clear correlation was found between PD-L1 expression and prognosis. Among the patients with MPM, four survived for more than 2 years, with the longest being 9 years. Among MPM cases who received nivolumab, one patient with positive PD-L1 staining in the sarcomatoid survived, whereas the other with negative PD-L1 staining did not.

Conclusion: The present study showed that sarcomatoid carcinoma had a higher PD-L1 expression compared to non-small-cell lung cancer and that both PSC and MPM tended to exhibit PD-L1 positivity in the sarcomatoid compartment. Moreover, while immune checkpoint inhibitors may somewhat prolong the prognosis of both tumors, further studies with a larger cohort are necessary to confirm our results.

© 2021 The Authors. Thoracic Cancer published by China Lung Oncology Group and John Wiley & Sons Australia, Ltd.

In plain English

This study at St. Marianna University School of Medicine Hospital in Kawasaki, Japan, reviewed 16 consecutive patients diagnosed from January 2004 to December 2020: eight with pulmonary sarcomatoid carcinoma, a rare lung cancer, and eight with malignant mesothelioma. The article reports no asbestos-exposure histories for these patients. Tumor samples were stained for PD-L1, a protein targeted by some immune-based drugs. Four of the eight lung cancers (50%) and one of the eight mesotheliomas (12.5%) were PD-L1-positive. In three of the four positive lung cancers, staining was only in the sarcomatoid part. No clear link was found between PD-L1 and survival in the lung cancer group. Of two mesothelioma patients given nivolumab, the PD-L1-positive patient had a partial response and the PD-L1-negative patient's disease progressed. Four mesothelioma patients, all stage I at diagnosis, survived more than 2 years, the longest 9 years. The authors concluded that immune checkpoint drugs can prolong survival in both tumors to some extent. They noted that the single-center, retrospective design and small sample limit the results.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Single-center retrospective case series reviewing consecutive patients' records and tumor tissue, with PD-L1 and vimentin immunohistochemistry
• Who was studied: 16 consecutive patients diagnosed by surgical resection or biopsy at St. Marianna University School of Medicine Hospital, Kawasaki, Japan, January 2004 to December 2020. The group included eight with pulmonary sarcomatoid carcinoma (median age 72.5, seven male) and eight with malignant pleural mesothelioma (median age 66.5, seven male; seven stage I and one stage III).
• Exposure: No asbestos-exposure histories are reported for the study patients; asbestos is mentioned only as background, as a known association of mesothelioma. The factor studied was tumor PD-L1 status measured by immunohistochemistry: positive meant more than 1% of tumor cell membranes stained, negative meant less than 1%. The study related this to age, sex, stage, histological type, treatment (including cisplatin plus pemetrexed and nivolumab) and survival.
• Main results:
  • Pulmonary sarcomatoid carcinoma: 4 of 8 cases (50%) were PD-L1-positive in tumor cells.
  • Pulmonary sarcomatoid carcinoma: in 3 of the 4 PD-L1-positive cases (including the 2 with high expression), staining was only in the vimentin-positive sarcomatoid compartment. The remaining case was positive in the epithelial areas.
  • Malignant mesothelioma: 1 of 8 cases (12.5%) was PD-L1-positive. According to Table 2 this was an epithelioid-type tumor.
  • Malignant mesothelioma: the PD-L1-positive patient received nivolumab after two courses of cisplatin plus pemetrexed and achieved a partial response.
  • Malignant mesothelioma: a PD-L1-negative patient who received nivolumab as second-line treatment stopped it because the disease progressed.
  • Pulmonary sarcomatoid carcinoma: no clear correlation was found between PD-L1 expression and prognosis. Two patients survived about 10 years and the rest died within 5 years after metastasis.
  • Malignant mesothelioma: four patients survived more than 2 years, the longest 9 years, and all four had stage I disease at diagnosis.
  • Malignant mesothelioma: all eight specimens were highly positive for vimentin.
• The authors' conclusion: The authors concluded that sarcomatoid carcinomas had higher PD-L1 expression than non-small-cell lung cancer, and that PD-L1 expression tended to occur in the sarcomatoid compartment of both pulmonary sarcomatoid carcinoma and mesothelioma. They also concluded that immune checkpoint inhibitors can prolong the prognosis of both tumors to some extent.
• Limitations the authors state:
  • Single-center, retrospective design means certain biases might exist.
  • The sample size was small and may be inadequate for reliable results; larger studies are needed.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Mesothelioma.

Medical terms in this study, explained in our Lexicon: Sarcomatoid, Carcinoma, Mesothelioma, Immunohistochemistry, PD-L1, Pleural Mesothelioma, Surgical Resection, Biopsy.

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