Written by Joyce Smith, BS. This study compares the clinical characteristics of a young subset of mesothelioma patients to those who are older and generates survival times for both groups from the data.
Malignant mesothelioma is an aggressive and often fatal cancer that originates in the tissue that lines several of our body organs. The most common primary sites of origin are the pleura (80 – 90 %) and the peritoneum (10 – 15%) and the least common sites (rare) are the pericardium and lining of the testis. (1)
Mesothelioma has three main subtypes of tumors: epithelioid, biphasic and sarcomatoid. Epithelioid tumors are the most common and offer better survival duration. Surgery is a feasible treatment option when disease progression is not advanced and is usually done in combination with other treatment modalities such as chemotherapy and radiation. In advanced diseases where surgery is not an option, chemotherapy is the standard treatment; (2) however, prognosis for these patients is poor, with median survival ranging from 10 – 13 months (2-4).
In a study of South African miners, Wagner and co-authors validated the link between occupational or environmental exposure to asbestos and the subsequent development of mesothelioma (5). After asbestos exposure, the risk of developing mesothelioma increases with time and peaks at 45 years for pleural mesothelioma. For peritoneal mesothelioma the risk continues to rise for the duration of life (6).
Up to 20 % of mesothelioma patients have had no previous asbestos exposure. For these patients, the risk factors include:
- Radiation exposure (7)
- Exposure to non-asbestos mineral fibers such as erionite (8)
- Simian virus 40 (9)
- A genetic predisposition to the disease (10).
Although mesothelioma is considered a disease of the elderly and offers a poor prognosis, there is a subgroup of patients with mesothelioma who are young (11). In this subgroup, the disease may be due more to a genetic predisposition for the disease or environmental exposure to carcinogenic mineral fibers such as erionite than to occupational asbestos exposure.
The objective of this study is to determine the characteristics and outcomes of this young subgroup of mesothelioma patients. Researchers used the Surveillance, Epidemiology, and End Results (SEER) database to extract mesothelioma cases from 1990 – 2010. From the individual records of patients who survived mesothelioma researchers were able to analyze clinical characteristics and outcomes and generate survival rates and median survival times.
Results:
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- 2 % (207 of 12345) of mesothelioma patients were young (under 40 years old) (51% males, 49% females)
- In the older than 40 age group of 12138 (98.3%) patients, males dominated (78% males, 22% females) p<0.0001
- In both age groups, mesothelioma was more frequent among Caucasians than other races (84 % of patients younger than 40 and 92% of older patients were white.) p<0.0008
- The most common subtype of mesothelioma for both young and older groups was epithelioid. p=0.012
- Frequency of pleural and peritoneal mesotheliomas are similar in the under 40 age group (47% pleural, 48% peritoneal ); however, pleural disease predominated in the older age group (90% pleural versus 9% peritoneal)
- 98 young patients (47%) had pleural mesothelioma compared to10,863 patients (98%) in the over 40 age group. p<0.0001
- Surgery for peritoneal mesothelioma is done more frequently in young patients (70% for ages 0-39, 47% for 40-60 year olds and 32% for those older than 65). p<0.0001
- Whether epithelioid, biphasic or sarcomatoid tumors, young patients with pleural mesothelioma had improved overall survival compared to older patients. (11 vs 8 months) P< 0.0001
Researchers concluded that while mesothelioma in the young is rare, it does occur and offers characteristics that are distinct from those of older patients. This study draws from a large national database and strives to provide a better understanding of mesothelioma in the young population. However, more studies are needed to fully understand the role that genetic susceptibility and mineral fiber exposure play in the pathogenesis of mesothelioma in the young.
Source: Thomas, Anish, et al. “Distinctive clinical characteristics of malignant mesothelioma in young patients.” Oncotarget 6.18 (2015): 16766.
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Posted August 25, 2015.
References:
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- Vogelzang NJ, Rusthoven JJ, Symanowski J, Denham C, Kaukel E, Ruffie P, Gatzemeier U, Boyer M, Emri S, Manegold C, Niyikiza C, Paoletti P. Phase III study of pemetrexed in combination with cisplatin versus cisplatin alone in patients with malignant pleural mesothelioma. J Clin Oncol. 2003; 21: 2636-2644.
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