By Nancy Meredith
An international collaboration effort is underway to study and improve the current staging system for malignant pleural mesothelioma. Led by the International Association for the Study of Lung Cancer (IASLC), and in collaboration with the International Mesothelioma Interest Group (IMIG), the Prospective Staging Project in Malignant Pleural Mesothelioma was formally initiated at a joint meeting of the IASLC-ISC Mesothelioma Domain and Advisory Committee in September 2010 in Kyoto, Japan, in conjunction with the biennial IMIG meeting.
The current mesothelioma staging system used by the American Joint Committee on Cancer, recognized as the official organization for formulating and publishing systems of classification of cancer, was developed by IMIG in 1995. Their “TNM” staging system is based on the relationship between Tumor size, lymph Node, and Metastasis. This staging system applies to only those tumors that arise from the pleura.
However, now mesothelioma experts believe there are improvements in the diagnosis and treatment of mesothelioma that warrant a revised staging system. Specifically, the IASLC indicates that some of the “T” descriptors in the current staging system are difficult to apply to patients who are managed non-surgically, and the “N” staging is nearly identical to non-small cell lung cancer (NSCLC), even though there are significant differences between the two cancers.
An accurate staging system is critical for determining the prognosis and effective treatment for mesothelioma patients. The treatment options are typically based on the extent of the cancer, which is determined by staging. A localized cancer would be identified as Stage 1, for example, and can involve a surgically removable tumor. Once the cancer cells have spread beyond that original location, and a higher stage level is designated, the mesothelioma is considered advanced and surgery is often no longer an option.
The process of modifying the staging system involves a detailed collection and analysis of mesothelioma patient data and samples leading researchers “to identify and validate additional descriptors for possible inclusion in future revisions to the TNM classification.” The data will be based on subjects that have been diagnosed with malignant pleural mesothelioma after January 1, 2010. The data will be compiled and stored in a secure, web-based, electronic data capture system provided by Cancer Research and Biostatistics (CRAB) in Seattle, Washington.
Some of the primary members of the committee include renowned mesothelioma experts Harvey Pass, M.D., NYU Langone Medical Center, Hedy Kindler, M.D.,University of Chicago and Jeremy Erasmus, M.D., M.D. Anderson Cancer Center.
The project leaders expect to submit recommendations for proposals for change regarding the 8th edition of the TNM classification for the staging of malignant pleural mesothelioma in January 2014. The recommendations will be based on data collected prior to December 31, 2012. The group intends to continue to collect prospective data to inform future revisions of the staging guidelines.
For more information see the IASLC website.