Research released in the January 2010 issue of the Journal of Thoracic Oncology sought to determine and validate the efficacy of the recent reclassification of the T category in the IASLC's Staging Manual in Thoracic Oncology.

The medical records of 1,393 patients with non-small cell lung cancer who underwent complete resection were thoroughly reviewed for pathologic findings and survival. The stage of all the patients was pathologically defined according to the present international staging system, previously revised in 1997. This study examined the relationship between the cut-off points of the tumor size for the new T category and the pathologic invasiveness

The tumor, node and metastatis (TNM) staging system is useful for both the clinical assessment of tumor progression and the determination of treatment plan (e.g., surgery, chemotherapy, radiation). In the forthcoming TNM classification, a revision with respect to lung cancer has been proposed by the International Association for the Study of Lung Cancer. The major revision is the T category, which makes an especially strict division by detailed cut points of tumor size (e.g., 2-, 3-, 5- and 7-cm). The proposed T revision has been determined and validated based on the overall survival date from a large international database.

Five-Year Postoperative Survival According to Primary Tumor Size, Presented by New T Category:

Classification / Primary Tumor Size / 5-Year Postoperative Survival

T1a / ≤ 2 cm / 78.0%
T1b / >2 - ≤3 cm / 63.3%
T2a / >3 - ≤5 cm / 46.4%
T2b / >5 - ≤7 cm / 38.8%
T3 / >7 cm / 21.4%

"The new T classification, which is based mainly on the tumor size, is therefore considered to be appropriate for the pathologic findings of the primary tumor," lead study author, Dr. Yano, summarizes the significance of the research findings. Furthermore, significant differences were observed among newly revised T subsets in at least one incidence of pathologic invasiveness, i.e. lymphatic, vascular, or pleural invasion.

Past chair and author of the IASLC's staging guide, Dr. Peter Goldstraw, confirms that "Any new addition to TMN is very important to the clinicians and researchers involved in that particular organ site. It happens that in the 6th edition there were no changes to TMN in lung cancer so this is very important; it's the first revision of TMN classification in lung cancer for 12 years. Indeed, it represents the most drastic change there has been in the past 30 years."

Dr. Goldstraw recently hosted an international roundtable explaining the changes applying to both clinical and patient perspectives of the staging revisions. Acknowledging the ongoing commitment, Dr Goldstraw explains that the "IASLC now has a responsibility to continue this central role in the formation of future classification of TMN and we have plans to build on the success of our process to improve among further revisions."

Source: Megan Richter
International Association for the Study of Lung Cancer