Prognostic factors of inoperable localized lung cancer treated by high dose radiotherapy

A retrospective study was made of the results of high dose radiotherapy (greater than or equal to 50 Gy) given to 171 patients with inoperable, intrathoracic non small cell lung cancer from January 1971-April 1973. Local control was dependent on the total tumor dose: after one year local control was 63% for patients treated with greater than 65 Gy, the two year local control was 35%. If treated with less than 65 Gy the one year local control was less than or equal to 40%. Tumor doses correlated with the size of the booster field. If the size of the booster field was less than 100 cm2, the one year local control was 72%; the two year local control was 44%. Local control was also influenced by the performance status, by the localization of the primary tumor in the left upper lobe and in the periphery of the lung. Local control for tumors in the left upper lobe and in the periphery of the lung was about 70% after one year, and about 40% after two years. The one and two years survival results were correlated with the factors influencing local control. The dose factor, the localization factors and the performance influenced local control independently. Tumors localized in the left upper lobe did metastasize less than tumors in the lower lobe, or in a combination of the two. This was not true for the right upper lobe. No correlation between the TNM system, pathology and the prognosis were found.