677 An analysis of latent period and survival factors of korean patients with malignant mesothelioma

Introduction

Malignant mesothelioma is an aggressive tumour occurring in mesothelioma cells of pleura and peritoneum. About 80% of malignant mesothelioma cases are known to be caused by asbestos. Malignant mesothelioma is known to have a very poor prognosis with an average survival period of about 12 months. The number of patients of malignant mesothelioma in Korea is smaller than that of some developed countries. However, mesothelioma has increased greatly in recent years in Korea, and it is expected to increase continuously considering asbestos consumption, as it happened in other countries which used large amounts of asbestos. It is important to investigate the epidemiologic characteristics and prognostic factors of malignant mesothelioma in Korea.

Methods

A total of 728 patients who received asbestos-related relief from malignant mesothelioma by 2014 were included in the study. In 2015, 150 (20.6%) out of 728 people were surveyed. Interviews were conducted with structured questionnaires for patients with malignant mesothelioma and their families. The age, sex, surgical status, route of exposure, and age at diagnosis of malignant mesothelioma patients were analysed using the proportional hazard model of Cox.

Results

Ninety eight (65.3%) males and 52 females (34.7%) had malignant mesothelioma according to sex. In the case of mesothelioma according to age, 49 cases (32.7%) were the highest in above 70 s, 42 cases (28.0%) in the 60 s, 40 cases (26.7%) in the 50 s, Followed by below 49 to 19 (12.7%). In this study, asbestos exposure source of subjects was 40.7% for occupational factors and 56.0% for environmental factors, which was higher than 59% of Kim, et al. ‘s (2009) study. The latent period was 35.0±15.8 years, which was mostly latent period of 30 years or more. And 39.1±15.1 years in the occupational asbestos exposure group and 32.2±15.7 years in the non occupational asbestos exposure group. The mean survival duration after diagnosis of mesothelioma was 19.9±27.2 months. Mean occupational exposure was 15.8±21.3 months in occupational asbestos exposure group and 22.8±30.5 months in non occupational asbestos exposure group. Gender, exposure type, and age at diagnosis did not significantly affect the risk of malignant mesothelioma death. The risk of death was 2.20 times (95% CI: 1.15~3.56) higher in the pleura than in the other sites of malignant mesothelioma. Also, according to the received surgery, the number of patients who underwent surgery was lower by 0.52 times (95% CI: 0.33~0.81) than those without surgery.

Conclusion

This study revealed that the site of onset and surgical treatment had an effect on the risk of death in patients with malignant mesothelioma. It is necessary to develop a new treatment and compensation method for malignant mesothelioma which is expected to increase rapidly in the future and to plan ways to minimise exposure to future asbestos.