Microwave hyperthermia in conjunction with radiotherapy in superficial tumours: correlation of thermal parameters with tumour regression / Hipertermia de microonda de conjunto con radioterapia en los tumores superficiales: correlación de los parámetros térmicos con la regresión del tumor

OBJECTIVE: The aim of the present study is to evaluate the correlation between the thermal parameters of hyperthermia and the clinical outcome in patients with superficial tumours. METHODS: In this study, 20 patients were included with either submandibular lymph nodes from head and neck cancer, or breast cancer relapses post-mastectomy. They were treated with radiation in combination with one session of433 MHz microwave hyperthermia (1 hour, 42.5 ºC-46 ºC). The dose of irradiation ranged from 54 to 60 Gy. The thermal parameters calculated were the minimum volume temperature, the maximum volume temperature and the time interval where the volume temperature was greater than 44 ºC. RESULTS: All patients responded positively to the combined treatment and 60% of the patients showed a complete response. Of the three parameters tested, the only parameter that was found to correlate with the reduction of the tumour diameter was the time with volume temperatures greater than 44 ºC (p < 0.001, Spearman rho). No moderate toxicity was observed. CONCLUSION: Microwave heating should be over 44 ºC for favourable treatment response, when combined with radiotherapy. More patients are needed to confirm the above results.

OJETIVO: El objetivo del presente estudio es evaluar la correlación entre los parámetros térmicos de la hipertermia y el resultado clínico en pacientes con tumores superficiales. MÉTODO: En este estudio, se incluyeron 20 pacientes con ganglios linfáticos submandibulares de cáncer de cabeza y cuello, o post-mastectomía por recidivas de cáncer de mama. Los pacientes fueron tratados con radiación en combinación con una sesión de hipertermia de microondas de 433 MHz (1 hora, 42.5 ºC-46 ºC). La dosis de irradiación osciló entre 54 y 60 Gy. Los parámetros térmicos calculados fueron la temperatura de volumen mínimo, la temperatura de volumen máximo y el intervalo de tiempo donde el volumen de la temperatura fue superior a 44 ºC. RESULTADOS: Todos los pacientes respondieron positivamente al tratamiento combinado y el 60% de los pacientes demostrados una respuesta completa. De los tres parámetros probados, el único parámetro que se comprobó que se correlaciona con la reducción del diámetro del tumor fue el tiempo con temperaturas de volumen superiores a 44 ºC (p < 0.001, rho de Spearman). No se observó ninguna toxicidad moderada. CONCLUSIÓN: Calentamiento por microondas debe estar por encima de 44 ºC para que la respuesta sea favorable al tratamiento en combinación con radioterapia. Se requieren más pacientes para confirmar los resultados anteriores.

Microwave hyperthermia in conjunction with radiotherapy in superficial tumours: correlation of thermal parameters with tumour regression.

OBJECTIVE: The aim of the present study is to evaluate the correlation between the thermal parameters of hyperthermia and the clinical outcome in patients with superficial tumours. METHODS: In this study, 20 patients were included with either submandibular lymph nodes from head and neck cancer, or breast cancer relapses post-mastectomy. They were treated with radiation in combination with one session of 433 MHz microwave hyperthermia (1 hour, 42.5 °C-46 °C). The dose of irradiation ranged from 54 to 60 Gy. The thermal parameters calculated were the minimum volume temperature, the maximum volume temperature and the time interval where the volume temperature was greater than 44 °C. RESULTS: All patients responded positively to the combined treatment and 60% of the patients showed a complete response. Of the three parameters tested, the only parameter that was found to correlate with the reduction of the tumour diameter was the time with volume temperatures greater than 44 °C (p < 0.001, Spearman rho). No moderate toxicity was observed. CONCLUSION: Microwave heating should be over 44 °C for favourable treatment response, when combined with radiotherapy. More patients are needed to confirm the above results.