Computerized tomography scanning and the planning of high-dose radiotherapy for pleural mesothelioma: a report of five patients

Our plain-English summary of Computerized tomography scanning and the planning of high-dose radiotherapy for pleural mesothelioma: a report of five patients, by P.B. Bricout, M.J. Engler (International Journal of Radiation Oncology, Biology, Physics, 1981).

The study

• Authors: P.B. Bricout, M.J. Engler
• Journal: International Journal of Radiation Oncology, Biology, Physics
• Published: 1981;7(6):821-6
• Type of article: Case report
• Cited by: 7 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

A lung-sparing external beam irradiation technique for treatment of pleural mesothelioma is discussed, with clinical parameters determined from computerized tomography (CT) scans and orthogonal chest radiographs. Parallel opposed, C-shaped fields of 42 MV photon beams from a betatron are used for coverage of apical, mediastinal and diaphragmatic pleura; eccentrically arcing photon beams (shell fields) irradiate the parietal pleura. Angle of eccentricity of the shell field is obtained graphically from the desired field width and untreated inner radius. Wedges are used to improve the uniformity of dose. Measured isodose distributions of the shell technique are presented. For therapy machines unable to rotate around their sources, the use of blocking to create the shell field is described. The value of CT as an aid in staging and radiotherapeutic treatment planning of pleural mesothelioma is illustrated. Five patients, four with advanced disease, have been treated for palliation. One patient has responded well.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.

In plain English

This report described a radiation technique for pleural mesothelioma and its use in five patients. It did not study asbestos exposure or give the patients' exposure histories. The technique aimed to treat the whole pleura while sparing the lung. It used C-shaped photon fields plus rotating "shell" fields, sized from CT scans and chest X-rays, although one patient had no CT scan. The authors reported that the untreated inner cylinder inside the shell received about 30% of the tumor dose. CT scans showed tumor missed by standard chest X-rays, including opposite-side spread in one patient. The first two patients received the shell technique as a 2500 rad boost after earlier radiation. Both did poorly, dying 2 and 7 months after treatment. Three patients were treated with 5000 rad in 25 fractions. One died 10 months after treatment, and one was lost to follow-up at 10 months with spread of disease. One was alive with no evidence of disease 29 months after treatment. The authors concluded that radiotherapy results remained discouraging. They suggested a pilot study combining radiation with a chemotherapy drug such as doxorubicin.

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: Brief communication describing a radiotherapy planning technique, with a report of five treated patients (case series)
• Who was studied: Five patients with a histological diagnosis of pleural mesothelioma. Three are described as white males, aged 57, 42 and 65. The authors were at Boston University Medical Center and began developing the technique in 1978.
• Exposure: Asbestos exposure was not studied, and the patients' exposure histories were not given. The introduction mentions earlier studies linking asbestos to mesothelioma. What the article studied was radiation treatment: 42 MV photon C-shaped fields and rotating shell fields. Doses were 5000 rad, or a 2500 rad boost after 4000-5000 rad from an earlier technique.
• Main results:
  • The authors reported that the dose delivered to the untreated inner cylinder enclosed by the shell was about 30% of the tumor dose. They described this as a substantial improvement over full lung techniques.
  • In Patient 1, CT scans showed tumor whose size and shape could not be described from conventional chest radiographs.
  • In Patient 4, a CT scan found disease spreading to the opposite side, with no localizing symptoms.
  • Patients 1 and 2 received the shell technique as a 2500 rad boost after earlier radiation. Both did poorly. Patient 1 died two months after completing the boost. Patient 2 died 7 months after completing treatment.
  • Patients 3 to 5 received 5000 rad in 25 fractions as their first treatment.
  • Patient 3 developed spread of mesothelioma into the abdomen and died 10 months after the end of radiotherapy.
  • Patient 4 was lost to follow-up 10 months after treatment. Before that, at 8 months, CT had shown spread of disease to the opposite side.
  • Patient 5 responded to treatment and was alive with no evidence of disease 29 months after treatment.
• The authors' conclusion: The authors concluded that, despite higher doses and lung-sparing techniques, results of radiotherapy for pleural mesothelioma remained discouraging. Only one of the five patients responded favorably. They suggested that radiotherapy alone may not be sufficient and proposed a multimodality pilot study, perhaps combining radiation with a chemotherapy agent such as doxorubicin.
• Limitations the authors state:
  • The authors suggested that the failure of local control in two patients may have resulted from remaining unevenness of dose within the pleural fields.
  • Abdominal CT scans were not obtained for these patients, although the authors considered them desirable for initial staging.
  • No CT scans were available for Patient 5, whose treatment was planned from radiographs and a nuclear medicine scan.

Topics

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

Medical terms in this study, explained in our Lexicon: Pleural Mesothelioma, Chest X-Ray, Pleura, Parietal Pleura, Staging.

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