Interstitial radiation implantation for unresectable nonoat cell carcinoma of the lung. Techniques and preliminary results.

The majority of lung cancers are unresectable at diagnosis. The radiation tolerance of the surrounding spinal cord and heart limits the external radiation therapy dose. Interstitial radiation implantation was utilized to deliver higher radiation dose, sparing the surrounding normal tissues in patients with unresectable nonoat cell cancers of the lung less than 8 cm in diameter localized to the thorax with no associated pleural effusion. The methods of implantation included permanent interstitial iodine-125 implantation of the gross disease in the lung and/or lymph nodes delivering about 120 Gy (12,000 rads) in 1 year and removable iridium-192 interstitial implantation of residual disease in the mediastinum, chest wall, or margin or resection in the lung, delivering about 30 Gy (3000 rads) in three days. Supplementary external radiation therapy of 40 Gy (4000 rads) in 4 weeks is delivered 4-6 weeks after implantation. The interstitial implant procedure adds only about 45 minutes to 1 hour to the operating time, and converts a palliative procedure into a potentially curative treatment. This article presents our experience with 11 cases, with early short-term follow-up results, and is designed to stimulate others to evaluate a similar approach to improve local control and survival in unresectable lung cancers.