Methods and applicator apparatus are disclosed for brachytherapy treatment of tissue surrounding a cavity in a patient, particularly a resection cavity. In treatment regimes requiring recovery time between successive radiation treatments, applicators of the invention are retained under the skin, with the skin allowed to at least partially heal, and are re-accessed later for one or more subsequent treatments. To reduce patient discomfort an anesthetic agent can be infused through the applicator to patient tissue, for insertion, balloon inflation or removal of the applicator.