Growth kinetics of small cell carcinoma of the lung

Tumor volumes prior to initial therapy for 33 patients with small cell carcinoma of the lung were determined from serially measurable roentgenographic lesions. Tumor doubling times were calculated for 20 patients who had two or more serial measurements. Pretreatment tumor volumes ranged from <5 to 485 cm³, with a median of 87 cm³, a log mean of 61 cm³, and an arithmetic mean of 103 cm³. The tumor doubling times (DT) ranged between 12 and 209 days, with a median of 53 days, a log mean of 59 days, and an arithmetic mean of 79 days. The tumor growth rate, expressed by tumor doubling time, was correlated with the tumor volume (r = -0.533, P < 0.05); and volume dependency of the tumor growth rate, as specified in Gompertzian growth, was demonstrated. Patients with DT < 79 days had a median duration of survival of 15 months, which was significantly longer (P = 0.046) than the median survival of 8 months for patients with DT > 79 days.