Radiofrequency Ablation Complements Radiation in Patients With Unresectable Early NSCLC

NEW YORK-Radiofrequencyablation (RFA) plus radiation is aneffective and well-tolerated minimallyinvasive technique that warrantsfurther investigation in early-stagenon-small-cell lung cancer (NSCLC),Thomas A. Dipetrillo, MD, said atthe 10th Annual International Conferenceon Screening for Lung Cancer.In 25 NSCLC patients with T1and T2 disease treated with the RFA/radiation combination, 1-year survivalwas 81%, reported Dr. Dipetrillo,assistant professor of radiation oncology,Brown University MedicalSchool. "Our data suggest that thesetwo therapies are very complementary,"he said.RFA is a newer technology thatresearchers believe will be useful inearly NSCLC cases that cannot be surgicallyexcised because of coexistingmorbidities, Dr. Dipetrillo said.The RFA technique involves insertionof a probe into the tumor. Ahigh-frequency electrical current isgenerated and applied through theprobe. Agitation of ions in tissue resultsin frictional heat, causing coagulativenecrosis of tissue."The heat can be directed at a relativelywell-defined area, depending onthe type of probe that is used," Dr.Dipetrillo said. "You can get to abouta 3-cm spheroid type shape, and theprobe can be put in through CT fluoroscopy,with excellent positioning."According to Dr. Dipetrillo, RFAis a single-day procedure that is "aboutas safe as biopsy itself. . . . We haven'tseen any increase in toxicity abovebiopsy, at least for RFA alone." Theprocedure takes about 1 to 3 hours inthe imaging room and patient recoverytakes about 3 hours.In their initial experience with RFAalone, Dr. Dipetrillo and his colleaguesnoted that starting at about a yearafter the procedure, there were someincreases in density along the peripheralregion of the initial area of ablation.Going on the theory that notenough current was being generatedto allow appropriate heating, theywent on to combine RFA with radiation.Phase I StudyAt Rhode Island Hospital, the investigatorsundertook a phase I trialincluding 25 consecutive patients (agerange, 58 to 85) with T1 or T2 NSCLC(biopsy proven and PET-confirmednode negative). All patients were medicallyinoperable, typically due tocardiopulmonary disease, and hadreceived up-front cytoreduction withRFA, followed by 3D conformalradiation ± chemotherapy. Follow-upincluded PET (6 and 12 months) andCT (every 3 months for the first year, then every 6 months). Pulmonaryfunction tests were given 6 monthsafter completion of therapy.The mean lesion size treated was3.4 cm. Immediately after the procedure,the pneumothorax rate wasabout 12%, consistent with what isexpected from biopsy. There were notreatment-related deaths or grade 3-4toxicities, "although these were veryhigh-risk patients," he said. Investigatorsnoted no significant changesin pulmonary function tests.With a median follow-up of 17.2months (range, 4 to 48 months), 1-year survival is 81% (16 of 25 patients).There have been five cancerdeaths (four in T2 patients); the remainingfour deaths were related toCOPD or cardiovascular disease andoccurred at least 6 months after RFA/radiation treatment. Of five patientswho developed metastatic disease,four were T2 patients. There was onelocal and one intrathoracic recurrence,both in T2 patients.Brachytherapy StudiedNow, the investigators have movedfrom external radiation to brachytherapy.In an open protocol with anenrollment goal of 25 patients withlesions 3 cm or less in size, they areusing brachytherapy immediately followingRFA. "We have inserted abrachytherapy catheter to try to isolatean area of treatment and give 18to 20 Gy to approximately 5 mmaround that area," he said. To date,12 of 14 patients have been treatedsuccessfully. "With median follow-upof 8 months, there were no local orsystemic recurrences and very littletoxicity, although these are very earlydata," Dr. Dipetrillo said.