It is the first big overhaul of a decades-old method used to predict survival and help determine whether a lung cancer patient will have surgery, chemotherapy or be treated at all.
The new guidance is to be presented at a conference of lung cancer specialists in Seoul, South Korea, that starts Saturday. It is expected to be adopted by policy-making groups in the next year.
Lung cancer is the world's top cancer killer, claiming 1.3 million lives each year. In the United States, 213,380 new cases and 160,390 deaths from the disease are expected this year.
Nearly 60 percent of people die within one year of diagnosis, and nearly 75 percent die within two years, American Cancer Society statistics show.
In treating it, doctors use a formula called tumor staging. It is based on a tumor's size, how far it has spread and other factors to predict a patient's survival odds and to guide treatment.
The current system was developed from about 5,000 tumor samples from University of Texas M.D. Anderson Cancer Center in Houston decades ago
- before improved scanning technology was available to evaluate a cancer's spread.
The new plan is based on 100,000 tumor samples from around the world including Asia, where lung cancer rates are projected to climb because of trends in smoking, unhealthy lifestyles and aging populations.
It keeps four broad groupings but sorts people more precisely based on refined understanding of tumor characteristics.
The result: "There will clearly be shifting of patients from categories not operable to operable"
- as many as 10,000 a year in the United States, said Dr. David Johnson, a lung cancer specialist at Vanderbilt University in Nashville, Tenn. He reviewed the plan, which was partly published in a medical journal recently.
The stage of the tumor at diagnosis is the best predictor of survival. Only 20 percent of cases are diagnosed in Stages 1 or 2, when tumors are small and confined to a lung, Johnson said. About 30 percent to 40 percent are found in Stage 4, after they have widely spread. The rest are in the middle.
Five-year survival rates are 47 percent for Stage 1 and 26 percent for Stage 2, but only 8 percent for Stage 3, and 2 percent for Stage 4, according to the American College of Surgeons.
Most lung cancers are the type called "non-small cell," which is covered by the new staging system. The system was developed by the International Association for the Study of Lung Cancer, a group of lung cancer specialists from around the world.
Dr. Peter Goldstraw, a surgeon at the Royal Brompton Hospital in London, led the project, and Canadian scientists independently validated the recommended changes by comparing survival across geographic regions.
