About 30 percent of patients diagnosed with lung cancer are at stage III at the time of diagnosis. The five-year survival rate for stage IIIA lung cancer varies widely, and is about 23 percent on average. For stage IIIB lung cancer, the survival rate is about 10 percent.
When lung cancer reaches stage 3, it has spread from the lungs to other nearby. and 2000, the 5-year survival rate for stage 3A lung cancer was 14 percent.