Cryosurgery is a therapeutic method of treating neoplastic tissue by freezing in situ in order to achieve devitalization. Cell death results from exposure to severe cold (40° for at least one minute) as well as from the process of freezing and thawing which disrupts cellular integrity. Modern cryosurgical technique involves insertion of hollow probes into the tumor through which circulating liquid nitrogen and gaseous nitrogen can achieve tissue and tumor freezing and thawing for tumor control. Cryoablation is now a recognized approach to the treatment of various malignant tumors and it is generally well tolerated. This method has not been used to date in the treatment of soft tissue sarcomas despite the fact that they appear to be suited for this type of treatment.
To assess the feasibility and safety of cryosurgical ablation of soft tissue sarcomas utilizing a cryoprobe system.
Twelve patients with soft tissue tumors of the extremity were included in this IRB approved protocol. All patients had cryoablation of the tumor performed in the following manner. Skin flaps were raised surgically and protected with surgical packing. The superficial aspect of the tumor was then minimally exposed. One or more cryoprobes were then inserted into the tumor using intra-operative ultrasound to assure proper placement. Liquid nitrogen was then pumped through the probes and the formation of the resulting iceball was monitored with ultrasound. A temperature of at least -180°C was maintained for at least 10 minutes. The probes were then flushed with gaseous nitrogen to achieve a thaw to 0°C. The freeze/thaw cycle was then repeated. The wound was closed and patients were observed for clinical and metabolic signs of toxicity.
Diagnosis included malignant fibrous histiocytoma (5), malignant schwannoma (2), synovial cell sarcoma (2), leiomyosarcoma (1), aggressive fibromatosis (1) and atypical schwannoma (1). Sites of involvement included thigh (3), leg (2), buttock (3), groin (1), arm (1), forearm (1), scapula (1). Stage of the tumor included IIIB (1), IIB (2), IIA (4), IA (1), 3 (2).
Cryoablation was successfully performed in all 12 patients and no ablation was considered suboptimal because of technical considerations. Complications included peripheral nerve palsy (3), serous wound drainage (3). There were no cases of wound infection, deep venous thrombosis, pulmonary embolism, wound dehiscence, skin slough or metabolic abnormalities. Postoperative pain was incisional only. All 3 cases of peripheral nerve palsy showed signs of recovery, 2 within one week and 1 within 4 months.
Cryosurgical ablation of soft tissue sarcomas is technically safe and feasible. This method can be used in conjunction with other modalities in the treatment of soft tissue sarcomas. The complications associated with cryoablation of sarcomas are minor or transient and the procedure is well tolerated by patients. The role of cryosurgery in the management of soft tissue sarcomas needs to be elucidated as more data regarding safety and effectiveness become available.