CT guided cryoablation for locally recurrent or metastatic bone and soft tissue tumor: Initial experience

Background: Historically, local control of recurrent sarcomas has been limited to radiotherapy when surgical re-resection is not feasible. For metastatic carcinomas to the bone or soft tissue, radiotherapy and some interventional radiology treatment along with other systemic therapies have been widely advocated due to the possibility of disseminated disease. These techniques are effective in alleviating pain and achieving local control for some tumor types, but it has not been effective for prolonged local control of most tumors. Recently, cryoablation has been reported to have satisfactory results in lung and liver carcinoma treatment. In this study, we analyzed the clinical outcome of CT-guided cryoablation for malignant bone and soft tissue tumors to elucidate potential problems associated with this procedure. Methods: Since 2011, 11 CT-guided cryoablations in 9 patients were performed for locally recurrent or metastatic bone and soft tissue tumors (7 males and 2 females) at our institute. The patients' average age was 74.8 years (range 61-86) and the median follow up period was 24.1 months (range 5-48). Histological diagnosis included renal cell carcinoma (n = 4), dedifferentiated liposarcoma (n = 2), myxofibrosarcoma (n = 2), chordoma (n = 1), hepatocellular carcinoma (n = 1), and thyroid carcinoma (n = 1). Cryoablation methods, clinical outcomes, complications, and oncological outcomes were analyzed. Results: There were 5 recurrent tumors and 6 metastatic tumors, and all cases had contraindication to either surgery, chemotherapy or radiotherapy. Two and 3 cycles of cryoablation were performed for bone and soft tissue tumors, respectively. The average length of the procedure was 101.1 min (range 63-187), and the average number of probes was 2.4 (range 2-3). Complications included 1 case of urinary retention in a patient with sacral chordoma who underwent prior carbon ion radiotherapy, 1 transient femoral nerve palsy, and 1 minor wound complication. At the final follow up, 4 patients showed no evidence of disease, 2 were alive with disease, and 3 died of disease. Conclusions: Reports regarding CT-guided cryoablation for musculoskeletal tumors are rare and the clinical outcomes have not been extensively studied. In our case series, CT-guided cryoablation had analgesic efficacy and there were no cases of local recurrence post procedure during the follow-up period. Although collection of further data regarding use of this technique is necessary, our data suggest that cryoablation is a promising option in medically inoperable musculoskeletal tumors.