When screening for small cell lung cancer how big does a mass seen on a ct should be considered for investigation or benign .

THAT'S the question!: The smaller you make the cutoff, the more false-positives you get. Screening has led to a tremendous increase in cases found, but very little overall reduction in lung cancer mortality. Usually it's adenocarcinomas that we find, not small-cells. You decide what it all means. Best wishes. https://www.ncbi.nlm.nih.gov/pubmed/25326638