9th TNM lung cancer staging? What is new

S1A – Lung Cancer
9th TNM LUNG CANCER STAGING? WHAT IS NEW

Pang Yong Kek
University Malaya Medical Centre, Kuala Lumpur, Malaysia

The TNM Staging Classification of lung cancer has been revised periodically. Since 1996, this classification has been enriched with data from the International Association for the Study of Lung Cancer (IASLC) databases.

For the 9th TNM lung cancer classification, 76,518 patients from a total of 124,581 registered patients were available for analyses

The IASLC embraces AJCC criteria of a stage classification for formal adoption, which include: discrimination, calibration, generalizability, clinical relevance, and parsimony

Compared to the 8th edition, the 9th edition has greater granularity to allow better quantification of nodal diseases. In particular, the division of the N2 category into N2a and N2b subcategories. The proposed new N2 subcategories are as follows:

• N2a, involvement of single ipsilateral mediastinal or subcarinal nodal station,
• N2b, involvement of multiple ipsilateral mediastinal nodal stations with or without involvement of the subcarinal nodal station.

The extent of nodal disease has been demonstrated to significantly affect the prognosis of the patient, based on the number of nodal zones and nodal stations involved

In addition, T1N1 was downstaged from eighth edition stage IIB to ninth edition stage IIA.

Another subcategorisation involves dividing M1c into M1c1 and M1c2

• M1c1 (multiple extrathoracic metastases in a single organ system) and
• M1c2 (multiple extrathoracic metastases in multiple organ systems)

This subcategorisation does not change the stage of disease (both remain in stage IVB). However, it results in better refinement of the prognosis

In conclusion, the 9th TNM classification involves the subdivision of the N2 lymph node station and the M1c distant metastasis, with more granularity.