[Relation between the local effect of thermoradiotherapy and the prognosis for recurrent lung cancers]

From October 1986 through December 1991, 30 patients with locally recurrent lung cancer were treated by local hyperthermia combined with radiotherapy at the Kawasaki Medical School Hospital. Local heat was applied with 13.56 MHz radiofrequency (RF) capacitive heating equipment twice a week after radiotherapy for 40-60 minutes per session. The tumor temperatures of only a few patients (three patients) could be measured directly by thermocouples inserted into the tumors because of anatomical difficulties. Based on thermometrical results, it was estimated that the maximum tumor temperature was about 41 degrees C. When we consider the extensive low density areas often appearing in CT scan images following this combined therapy (NR2), the tumor response was as follows: CR 0, PR 5 (18%), NR 13 (40%), NR2 10 (36%), and PD 0. The local response rate (CR+PR+NR2) was 54%. The median survival time after the onset of retreatment was 12.8 months in PR cases, 7.1 months in NR cases and 24.1 months in NR2 cases. There was a statistically significant difference (p < 0.01) in the median survival times for NR and NR2 cases. From the standpoint of prognosis, we concluded that NR2 was a condition comparatively similar to clinical PR.