Clinical estimation of the growth rate of lung cancer

It is well known that the growth rate of lung tumors is closely related to prognosis and is an important determinant of responsiveness to therapy and curability. In this study, the velocity of tumor growth was calculated by dividing the area of the lesion at presentation divided by the time elapsed since symptoms were first noted. This parameter was applied to a group of patients with lung cancer and the predictive value of the velocity of tumor growth was assessed. Survival expectancy was found to be closely related to the growth rate of the tumors. The median survival time of patients with more slowly growing tumors was 102 weeks, while that of patients with fast-growing tumors was 30 weeks (log-rank test, p=0.00001). Linear regression analysis between velocity of tumor growth and tumor cell proliferation as measured by the PCNA-labelling index revealed a significant correlation between these two parameters. In conclusion, the velocity of a tumor measured in this way is an independent and significant prognostic factor for patients with lung cancer and may be used to non-invasively assess lung cancer proliferation in vivo, identifying rapidly growing tumors with poor prognosis that could benefit from a more aggressive therapy.