What stage is my cancer, doc?
This is often the first question we get asked when meeting with a patient newly diagnosed with lung cancer. In this blog, I would like to briefly review the notion of lung cancer staging and its implications.
Staging allows us to define the extent of a cancer and determine its best available treatment. It also allows us to statistically estimate the prognosis of the cancer. Finally, adequate staging allows us to group patients with cancers of similar extent across different institutions or even countries and evaluate the efficacy of the treatment strategies and compare with new ones.
Staging can be clinical or pathological. Clinical staging is based on the information we obtain from X-rays and scans as well as from procedures where samples (biopsies) of different tissues are obtained in an effort determine what structures may be involved with the cancer. Pathological staging is only available when the cancer has been removed by surgery: i.e. when the pathologist has measured the size of the tumor, its extent and whether or not any lymph nodes were involved with cancer. One should be aware that pathological and clinical stagings don’t always concord 100%. Sometimes clinical staging under-evaluates how extensive the cancer may be, and at times it over-evaluates it, particularly when clinical staging is based only on X-ray information. This is particularly true with the evaluation of lymph nodes that drain the area where the cancer has come from. The role of your lung cancer surgeon in adequately gathering that information to develop the best treatment plan cannot be emphasized enough.
The system we use to define a stage is called the TNM system.