Chemotherapy induced pathologic complete response in malignant pleural mesothelioma: a review and case report

Our plain-English summary of Chemotherapy induced pathologic complete response in malignant pleural mesothelioma: a review and case report, by C. Bech, J.B. Sørensen (Journal of Thoracic Oncology, 2010).

The study

• Authors: C. Bech, J.B. Sørensen
• Journal: Journal of Thoracic Oncology
• Published: 2010;5(5):735-40
• Type of article: Case report, Review
• Cited by: 12 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Introduction: Malignant pleural mesothelioma is a rare aggressive disease with a poor prognosis and usually modest responses to chemotherapy. Complete responses (CRs) to chemotherapy are rare. Evaluation is usually based on radiology, and CR is therefore clinical CR (cCR) and whether this indicates absence of viable tumor cells is unknown. We have observed two cases of CR which at subsequent surgery were histologically verified, thus being pathologic CRs (pCRs). pCR after chemotherapy is thus possible but rare, and we here present the cases from our institution together with a review on the literature available on the subject.

Methods: A literature search using relevant keywords was performed in PubMed and MedLine.

Results: A larger number of reports on cCR but only five reports on pCR were identified. All published cases of pCR, 16 patients in five trials, are presented and discussed, and larger trials reporting cCR are mentioned. pCR did not in all cases correspond to cCR. The cases having pCR identified all had the epithelial or unknown subtype, and all had early-stage disease before treatment.

Conclusion: pCR is possible but rare, and a pCR does not always require a cCR. So far reported cases of pCR have all had the epithelial or unknown subtype and pretreatment stages have been low. The cases in our institution also had epithelial subtype but had stage III disease ,and it thus seems possible to obtain a pCR despite a larger tumor burden.

In plain English

This review covered published reports and two patients with malignant pleural mesothelioma from the authors' Copenhagen hospital. It looked for 'pathologic complete response': no living cancer cells found under the microscope after treatment. Both patients came from a 56-patient study of epithelial mesothelioma planned as chemotherapy, surgery and radiation. The woman, with no known asbestos exposure, had chemotherapy and surgery without radiation. No cancer cells were found, and she was alive without signs of relapse 14 months later. The man, who had been asbestos exposed, had one tiny focus of cancer cells left. He relapsed after 15 months and died 39 months after diagnosis. Two published trials of gamma-interferon or interleukin-2 given into the chest, with 111 patients, reported nine responses judged by biopsies, which the authors said could miss remaining cancer. Four studies with 171 patients in total, including the authors' own, gave seven responses judged from whole surgical specimens. The authors counted the man among these despite his remaining cells. All reported cases were of the epithelial or an unknown subtype. The authors concluded such responses are possible but rare and, citing their two stage III patients, may occur in more advanced disease.

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: Literature review (PubMed and Medline search, September 2009) combined with two case reports from the authors' own institution
• Who was studied: Two patients with epithelial malignant pleural mesothelioma, both stage III: a 59-year-old woman and a 62-year-old man. They came from a study of 56 patients with epithelial malignant pleural mesothelioma at the Department of Oncology, Finsen Centre, Copenhagen, Denmark. The review also covered published trials and reports of complete response.
• Exposure: The exposure studied was treatment, not asbestos. The authors' study planned induction chemotherapy with pemetrexed plus cisplatin or carboplatin, followed by surgery and chest radiation. Some reviewed reports used intrapleural gamma-interferon or interleukin-2 rather than chemotherapy. Asbestos history was given only for the two cases: the woman had no known asbestos exposure, and the man had been asbestos exposed.
• Main results:
  • Case 1 (woman, stage III): her planned extrapleural pneumonectomy was converted to a pleurectomy. No malignant cells were found in the removed pleura despite examination of 100 slides.
  • Case 1 received no postoperative radiotherapy or any other further treatment. She was alive without signs of relapse 14 months later.
  • Case 2 (man, stage III): one microscopic focus of a few malignant cells was found in the removed lung and pleura. The authors described this as very close to a pathologic complete response. He relapsed after 15 months and died 39 months from initial diagnosis.
  • In the two recent phase III chemotherapy trials reviewed, complete response on imaging was rare. The Vogelzang et al. trial had none, and the van Meerbeeck et al. trial had two (1%). Together this was 2 of 661 patients (0.3%).
  • Two published trials of intrapleural gamma-interferon or interleukin-2 (Boutin et al. and Astoul et al.) included 111 patients. They reported nine biopsy-defined pathologic complete responses. Biopsies were done only when imaging showed response (or, in one trial, stabilization).
  • Three published reports (115 patients) plus the authors' own study (56 patients) gave 171 patients in total. Among them, seven pathologic complete responses were confirmed from whole surgical specimens (4%). Not all 171 patients had surgery; for example, 54 of the 77 patients in the Krug et al. trial proceeded to extrapleural pneumonectomy. The count of seven includes both of the authors' own patients.
  • In the Krug et al. trial, only 54 of the 77 enrolled patients proceeded to extrapleural pneumonectomy.
  • All reviewed cases of pathologic complete response had the epithelial or an unknown subtype. None were described in sarcomatous or biphasic mesothelioma.
  • Of the 14 pathologic complete responses in published reports, 10 had stage I disease and 1 had stage II disease. For the other 3, stage was not available. Both of the authors' own patients had stage III disease.
• The authors' conclusion: The authors concluded that pathologic complete response is possible but rare, and that it does not always require a complete response on imaging. Because their own two patients had stage III disease, they suggested such a response may be possible even with a larger tumor burden. By the article's own case descriptions, only the first of these two patients had no cancer cells found.
• Limitations the authors state:
  • Responses judged only by biopsies may not be true pathologic complete responses, because unbiopsied areas could still contain tumor cells.
  • The number of patients is too small to draw conclusions about survival after a pathologic complete response.

Topics

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

Medical terms in this study, explained in our Lexicon: Chemotherapy, Pleural Mesothelioma, Prognosis, Tumor Burden.

Related studies

• Hyperthermic intraoperative pleural cisplatin chemotherapy extends interval to recurrence and survival among low-risk patients with malignant pleural mesothelioma undergoing surgical macroscopic complete resection — D.J. Sugarbaker, R.R. Gill, et al. (2013)
• Radiological predictors of complete cytoreduction in 59 patients with peritoneal mesothelioma treated with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy at a UK referral centre — A. Chandramohan, A. Thrower, et al. (2017)
• Pathologic complete remission of malignant pleural mesothelioma after combined modality treatment: a case report — K. Moubax, V. Van Damme, et al. (2013)
• Complete pathological response after ceritinib for anaplastic lymphoma kinase-rearranged epithelioid peritoneal mesothelioma — S. Sakata, H. Rees, et al. (2021)
• Pathological complete response in malignant pleural mesothelioma patients following induction chemotherapy: Predictive factors and outcomes — B. Lau, S. Kumar, et al. (2017)
• A pathological complete response in malignant pleural mesothelioma after combination chemotherapy with Carboplatin and pemetrexed — S.C. Kao, B. McCaughan, et al. (2010)

Browse more research in Journal of Thoracic Oncology, or return to medical research.