Endoluminal brachytherapy in central lung cancer

Brachytherapy means the direct placement of a highly radioactive source ins ide a tumor mass. This can be done either by implanting the source directly into the tumor, via the natural route (endoluminal brachytherapy) or by pl acing the source into the tumor bed during tumor resection. Endoluminal bra chytherapy employing the afterloading technique with iridium-192 high dose rate (HDR) is largely applied for the curative and palliative treatment of endobronchial tumors due to its tumor-specific and long-lasting effect. End oluminal brachytherapy using flexible bronchoscopy and an HDR regimen can b e performed on an outpatient basis and is not more strenuous for the patien t than a diagnostic bronchoscopy. Symptomatic improvement can be achieved i n 70-80% of patients, and sometimes small tumors can even be cured. The aft erloading procedure can be combined with all other modalities of tumor ther apy. It can be used as 'boost' to conventional external irradiation and as local treatment modality in patients on systemic chemotherapy or as the onl y local treatment. HDR treatment is usually delivered with 1-6 fractions at an interval of 1-3 weeks and a dose of 3-20 Gy per fraction (at 1 cm from the source axis). In patients previously treated with external beam radiati on therapy and in the palliative setting, a regimen of 7-10 Gy (HDR) per fr action and a total of 2-3 fractions per treatment is recommended. However, the optimal dosage and fractionation schemes for the tumor therapy are stil l unknown and there is need for further studies. In about 10% of the patien ts, radiation bronchitis occurs, and there may be fatal hemorrhage, possibl y related to the therapy. Overall, endobronchial brachytherapy is a well-to lerated, not very aggressive treatment option, especially in patients with reduced performance status.