Clinical Investigations
Factors influencing the outcome of radiotherapy in malignant mesothelioma of the pleura—a single-institution experience with 189 patients

https://doi.org/10.1016/S0360-3016(98)00409-XGet rights and content

Abstract

Purpose: To determine the factors influencing the response to palliative radiotherapy (RT) in malignant mesothelioma of the pleura (MM).

Methods and Materials: A retrospective review was conducted of the records of all patients with mesothelioma who were referred to our institution between 1979 and 1996. A total of 227 RT series were administered to 189 patients with MM. Of these, 21 patients with chest wall nodules also received concomitant local hyperthermia.

Results: The median survival was 5 months from the start of RT and only 17% of patients were alive at 1 year after treatment. Chest pain and painful chest wall metastases were the main indications for RT. A higher local response rate was seen for patients treated with a 4-Gy per fraction scheme, vs. those receiving fractions of less than 4 Gy (50% vs. 39%). Pain recurrence occurred predominantly within the previous RT field, and pain recurred after a median of 69 days (range 32–363) in the group treated using 4-Gy fractions. When compared with a matched group, patients treated with combined RT and hyperthermia had higher response rates and fewer in-field recurrences.

Conclusions: RT provides local palliation in at least 50% of patients with MM who were treated using a 4-Gy/fraction scheme to a median dose of 36 Gy. The low response rates with RT alone suggest that combined RT and local hyperthemia should be further evaluated in MM.

Introduction

Malignant mesothelioma is an aggressive tumor that arises from the pleura and peritoneal surfaces and is linked to exposure to asbestos fibers (1). Because the period between asbestos exposure and presentation of the disease can be up to 40 years, the increasing incidence of malignant mesothelioma is expected to continue in the light of widespread, mainly industrial, exposure during the previous decades 2, 3.

Malignant mesothelioma of the pleura (MM) is almost invariably a fatal illness and median survival ranges from 9–12 months 4, 5. Important predictors for long-term survival include the performance status, histological subtype, and disease extent at the time of diagnosis 6, 7. Radical surgery is seldom possible because MM commonly exhibits diffuse pleural spread (8), but surgery has a role in selected patients who present with early disease (9). Local tumor progression can occur despite radiotherapy (RT) to doses of up to 70 Gy (10). Response rates to chemotherapy are commonly less than 20%, and combination chemotherapy has shown no advantage over single agents (11). In the light of these findings, it is not surprising that untreated patients have been reported to survive as long as treated ones 6, 7, and palliation remains the main goal of treatment for the majority of patients presenting with MM.

Chest pain is a frequent symptom and RT has been reported to provide palliation in between 50 to 68% of patients with MM 12, 13. However, the optimal dose and fractionation is unclear and no clear dose-response relationship for palliation has been established. We reviewed the results in 189 patients with MM who were treated with RT at the Daniel den Hoed Cancer Centre to determine the factors influencing the outcome of RT.

Section snippets

Patients

Between 1979 and 1996, a histological diagnosis of mesothelioma was made in 303 patients who were referred to our center. A total of 189 patients were treated with external RT for pleural mesothelioma (MM), and they received a total of 227 RT series. The remaining 114 patients included patients with MM who received only chemotherapy and/or immunotherapy (n = 59), supportive care only (n = 40), intrapleural radioactive phosphorus only (n = 3), and patients with peritoneal mesothelioma (n = 13).

Results

A univariate analysis showed that the stage of disease and performance status were prognostic factors for survival Fig. 1, Fig. 2. The majority of patients in this series had locally advanced or Stage III disease (Table 1). Despite the fact that 82% of patients had a performance status of ECOG 2 or better, the median survival was only 5 months from the start of radiotherapy, and only 17% of patients were alive at 1 year posttreatment. Patients with symptomatic disease showed a poorer

Discussion

In patients with MM, RT has been evaluated in curative, adjuvant, and palliative settings. The poor responses, even with high-dose RT 5, 10, have led to a purely palliative role for RT in many centers. Although prophylactic RT of thoracoscopy or biopsy sites reduces the incidence of subsequent chest wall recurrence 15, 16, this has not been shown to influence the course of the disease. It has long been advocated that RT techniques should minimize toxicity by using “high fraction size and small

Conclusion

These data confirm that RT is an active single agent in the palliation of MM; the use of hypofractionated RT schemes that are limited to sites of symptomatic disease can provide palliation of pain in at least 50% of patients. However, low response rates and the short duration of responses to RT indicate that relatively nontoxic measures such as HT added to RT should be further evaluated as palliative treatment of MM. In the light of the poor prognosis of patients with MM, such studies should

References (22)

  • P Ruffie et al.

    Diffuse malignant mesothelioma of the pleura in Ontario and Quebeca retrospective study of 332 patients

    J Clin Oncol

    (1989)
  • Cited by (0)

    View full text