Tumor doubling time and prognosis in lung cancer patients: evaluation from chest films and clinical follow-up study. Japanese Lung Cancer Screening Research Group.

A study was made of the relation between tumor doubling time and prognosis in lung cancer patients. Tumor doubling time was calculated in 237 patients from two serial chest x-ray films. The mean doubling time was 166.3 days, with 221.6 days for adenocarcinoma, 115.2 days for squamous cell carcinoma, 67.5 days for large cell carcinoma, 86.3 days for small cell carcinoma and 225.2 days for others. The patients were divided into three groups in a log-normal distribution of tumor doubling times 109.6 and 252.4 days. The patients with a doubling time of less than 109.6 days were classified as 'rapid growing', those with a doubling time of more than 252.4 days as 'slow growing' and those with a doubling time in between as 'intermediate growing'. The five-year survival rates were 23.3% for 81 'rapid growing' patients, 36.7% for 81 'intermediate growing' patients and 43.3% for 75 'slow growing' patients, with statistically significant differences between groups 'rapid growing' and 'intermediate growing' of P < 0.05 and between groups 'rapid growing' and 'slow growing' of P < 0.01. The five-year survival curves for those who underwent curable resections were 42.4% for 36 rapid growing patients, 53.7% for 31 'intermediate growing' patients and 70.1% for 43 'slow growing' patients. The difference between rapidly growing and slowly growing tumors was statistically significant (P < 0.05). Patients with the more rapidly growing tumors showed a tendency to have a poorer prognosis. It was confirmed that the doubling time of a tumor is an independent factor in the prognosis of lung cancer patients.