Medical Health Encyclopedia In N2, the cancer has spread to lymph nodes in areas in the middle of the chest that are still adjacent to the affected lung, to the nodes below the carina, or both regions. In N3 the cancer has spread to lymph nodes in areas in the middle of the chest that are adjacent to the opposite lung, to the hilum in the opposite lung, to lymph nodes in nearby or opposite muscle tissue, or to lymph nodes above the clavicle (collar bone). Stages M refer to metastasis. Text Continues Below In M0, metastasis has not occurred. In M1 distant metastasis has occurred. This includes the presence of a separate tumor in a different lobe.

Other Factors Determining Treatment Choices and Outcome

In addition, staging factors are also used to help determine treatment and outlook. The following suggest a more aggressive disease:

• The presence of respiratory symptoms.
• A tumor larger than 3 cm.
• High numbers of blood vessels in the tumor.

Researchers are always looking for more accurate ways to determine a treatment and prognosis for lung cancer. For example, some research involves specific biomarkers and related microscopic blood vessel development (angiogenesis) within tumors that might eventually help determine how aggressive a cancer is likely to be and the optimal treatment approach.

General Treatment Approach After Staging

If the cancer is still localized, surgery can produce five-year survival rates of up to 75% in stage I patients and up to 50% in stage II patients. Unfortunately, very few patients are diagnosed at such early stages. In locally advanced stages, the standard treatment is concurrent radiation and chemotherapy. However, even with this approach average survival times are less than two years. Even if an initial tumor has been surgically removed or irradiated, cancer recurrence rates are very high. (The risk for recurrence is lower in smokers who quit after treatment.)

On an encouraging note, advances in therapies for later stage lung cancer are now offering some hope for improving survival. Still at this time, the mortality rate for lung cancer is still extremely high, and reports of improved response or survival rates using drugs or combinations therapies do not mean cures. Ultimately, the patient must weigh a diminished quality of life using some aggressive treatments against a chance for a modestly prolonged life.