Prevention of malignant seeding at drain sites by hypofractionated radiotherapy in patients with pleural mesothelioma

Our plain-English summary of Prevention of malignant seeding at drain sites by hypofractionated radiotherapy in patients with pleural mesothelioma, by P. Kara, I. Ugur, C. Misirlioglu, et al (Asia-Pacific Journal of Clinical Oncology, 2010).

The study

• Authors: P. Kara, I. Ugur, C. Misirlioglu, B. Kücükplakci, A. Ozgen, Y. Elgin, T. Demirkasimoglu, E. Sanri
• Journal: Asia-Pacific Journal of Clinical Oncology
• Published: 2010;6(3):187-90
• Cited by: 5 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Aim: Unlike most other malignancies, malignant pleural mesothelioma (MPM) has a tendency to recur along tracks of chest wall instrumentation. We investigated the efficiency of hypofractionated radiotherapy for prevention of malignant seeding.

Methods: Twenty-one (six female, 15 male) patients diagnosed with pleural mesothelioma who had chest wall instrumentation and were treated with prophylactic radiotherapy were investigated retrospectively. All patients underwent surgery or thoracoscopy and/or talc pleurodesis, for diagnosis, staging procedures or as a treatment. All were treated with electron (12 MeV) external beam radiation therapy (21 Gy in three fractions over 3 days), directed to the instrumentation pathway after the invasive procedure. After completion of radiotherapy, four of 21 patients had also undergone chemotherapy.

Results: Nineteen of 21 patients were followed-up for a median period of 13 months (1-24 months) and two patients were lost just after the first month of the follow-up period. None of the followed patients had tumor progression in the treated area. Radiotherapy was well tolerated. The most common side-effect was grade 1 erythema (Radiation Therapy Oncology Group [RTOG] scale), noted in 13 treated patients.

Conclusion: Our experience showed that prophylactic radiotherapy to prevent malignant seeding in malignant mesothelioma at invasive procedure sites was effective and well tolerated in preventing malignant seeding, painful metastases after surgery or instrumentation in patients with pleural mesothelioma. Larger multicenter prospective trials are still needed to validate this treatment approach utility for it to be recommended routinely.

In plain English

This retrospective study from a radiation oncology department in Ankara, Turkey, reviewed the case notes of 21 patients (15 men, 6 women) with malignant pleural mesothelioma treated between January 2006 and January 2008. Seventeen of the 21 had been exposed to asbestos environmentally through "white soil." After chest procedures such as thoracoscopic surgery, biopsy or pleurodesis, all received preventive radiotherapy to the procedure sites: 21 Gy in three fractions over 3 days, to 33 sites in total. The aim was to stop the cancer from growing along the instrument tracks. Nineteen patients were followed for a median of 13 months, and two were lost after the first month. None of the followed patients had tumor progression in the treated area. Thirteen patients had mild (grade 1) skin redness. Nine patients had a recurrence of the cancer, and 15 of 19 died of disease progression. The authors concluded the treatment was effective and well tolerated, but said larger multicenter prospective trials are still needed. They noted there was no control group, the study was retrospective, and some follow-up was short.

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: Retrospective review of case notes at a single hospital, with no control group
• Who was studied: 21 patients (6 female, 15 male) with pathologically proven malignant pleural mesothelioma, median age at diagnosis 62 years (range 42 to 72), treated at Ankara Oncology Research and Education Hospital, Turkey, between January 2006 and January 2008
• Exposure: The treatment studied was preventive (prophylactic) radiotherapy with 12 MeV electrons, 21 Gy in three fractions over 3 days, given to 33 procedure or drain sites (one to three per patient) after invasive chest procedures. Background asbestos exposure was environmental, through white soil (no fiber type named).
• Main results:
  • 17 of 21 patients (80.95%) had environmental asbestos exposure through white soil, according to their medical history
  • 19 of 21 patients were followed for a median of 13 months (range 1 to 24 months); two were lost just after the first month
  • None of the followed patients had tumor progression in the radiation-treated area
  • 13 patients developed grade 1 erythema (RTOG scale); the authors reported no late effects such as skin fibrosis, necrosis or lung toxicity
  • Recurrence was seen in 9 patients: the first relapse was local in 7 (6 in the same hemithorax) and distant in 2
  • 15 of 19 patients (printed as 78.4%) died of disease progression after a mean survival of 11 months (4 to 16 months); 4 were alive with disease
  • Overall survival was 10.8 months for men and 12.8 months for women; the difference was not statistically significant (P = 0.063)
• The authors' conclusion: The authors concluded that prophylactic radiotherapy at invasive procedure sites was effective and well tolerated in preventing malignant seeding and painful metastases in pleural mesothelioma, but that larger multicenter prospective trials are still needed before it is recommended routinely.
• Limitations the authors state:
  • There was no control group
  • The study was retrospective
  • Follow-up was short for some patients

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, Thoracoscopy, Talc Pleurodesis, Staging, Chemotherapy, Erythema, Malignant Mesothelioma.

Related studies

• Prophylactic irradiation of intervention sites in malignant pleural mesothelioma — M.A. Froment, E. Fréchette, et al. (2011)
• Subcutaneous seeding after ultrasound-guided placement of intrapleural catheter. An unusual complication of the intracavitary palliative treatment of pleural mesothelioma — S. Sartori, I. Nielsen, et al. (1999)
• FDG PET/CT is useful for detecting infiltration to the port site in patients with malignant pleural mesothelioma — K. Kawaguchi, T. Taniguchi, et al. (2014)
• Prophylactic radiotherapy for procedure tract metastases in mesothelioma: a review — D.T. Arnold, A.O. Clive (2017)
• Should all patients who have mesothelioma diagnosed by video-assisted thoracoscopic surgery have their intervention sites irradiated? — M. Nagendran, A. Pallis, et al. (2011)
• Pseudo-tumor mimicking indwelling pleural catheter tract metastasis in mesothelioma — R.L. Shrestha, B.A. Wood, et al. (2014)

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