INOPERABLE ENDOBRONCHIAL OBSTRUCTING LUNG-CANCER TREATED WITH COMBINED ENDOBRONCHIAL AND EXTERNAL-BEAM IRRADIATION - A DOSIMETRIC ANALYSIS

Purpose: This study is a dosimetric review of our experience incorporating both external beam radiotherapy an endobronchial brachytherapy in the treatment of inoperable endobronchial obstructing lung cancer. Methods and Materials: Sixty-five patients with symptomatic inoperable endobronchial obstructing lung cancer received combined external beam radiotherapy and temporary endobronchial iridium (Ir)-192 implants between February 1987 and May 1991. External beam irradiation doses ranged from 55 to 66 Gy. Patients were given 2 to 4 temporary Ir-192 endobronchial implants at the site of endobronchial obstruction. Individual implant doses ranged from 2.7 to 10 Gy. Total implant doses ranged from 6 to 35 Gy. Total treatment doses ranged from 61 to 96.6 Gy. Results: Sixty-three percent of patients had a complete local endobronchial response to treatment and 23% had a partial response. Forty-seven percent of patients receiving a total dose of less than 70 Gy experienced a complete local endobronchial response to treatment while 83% of patients receiving a total dose of 85 Gy or greater experienced a complete local endobronchial response to treatment. Sixty-six percent experienced an improvement in their performance status using an Eastern Cooperative Oncology Group performance scale. Survival from the end of treatment was 38% at 1 year and 23% at 2 years, with the median survival at 8 months. Complications occurred in 9/65 (14%) of patients; 0% in patients receiving a total dose of less than 70 Gy, 10% in patients receiving a total dose of 70 to 84.99 Gy, and 24% of patients receiving a total dose of 85 Gy or higher. Conclusion: The data from this study again confirms the feasibility of this form of treatment for inoperable endobronchial obstructing lung cancer. In addition, there appears to be a dose response for both local response and complications.