The Experimental And Clinical Study Of Conformal Argon-helium Cryoablation For Lung Carcinoma

Objective1. To observe the ice ball performance of multi combined17G cryoprobes invitro model experiment.2. To investigate the acute pathological changes of PCT on normal lung tissueevaluated in a procine model.3. To investigate the technique, imaging features and therapeutic effects offine-needle conformal PCT for NSCLC.Materials and Methods1、Experiment in vitro model: Three17G cryoprobes were triangularly arrangedin a container with ultrasound gel. The ice ball performance was recorded.2、 Experiment in a procine model: The cryoprobe was placed in a normal lungtissue to observe the acute macroscopic and microscopy changes aftercryoablation.3、 Clinical application: In this study,231patients with NSCLC were treated byCT-guided conformal PCT using17G probes. They were separated into threegroups: group A includes63diameters less than3cm, group B includes77diameters between3cm to5cm, and group C includes91diameters greaterthan5cm. For group A, double-needle clamping cryoablation was performed.For group B and C, multiple-needle conformal intratumoral was placed. TheFACT-G score, treatment response and survival rate were tested to evaluatedthe efficacy of the surgery.Results1、Multi-needle combination demonstrates the advantage of creating a large-volume ice ball, aggregate ice ball is bigger than that obtained byseparate cryoprobes.2、Macroscopically the cryolesion appeared as a well-defined hemorrhagicregion. Microscopically, the acute changes caused by cryoablation weredivided into three different parts: complete necrosis in the centre area withdestruction of vessel and airway structures, alveolar exudation andconsolidation in the periphery of the cryolesion with preserved large vesselsand airways, and transitional change between peripheral area and normaltissue.3、The technique, imaging features and therapeutic effects of fine-needleconformal PCT for NSCLC was obtained. For group A, intraoperative CTscan showed the frozen areas extended beyond the edge of the lesions morethan1.0cm，the lesion attenuated, narrow-band-like encircled translucencyaround the lesions and “target sign” with ground-glass density of theperipheral lung tissue. For group B, CT scan during the procedure showed iceball fully covered the lesion, lobulation and speculation disappeared and thetumor size slightly enlarged. The lesion volume gradually reduced in varydegree. For group C, intraoperative CT showed the frozen areas covered70%-90%of the tumor, there was no frozen injury to its surrounding lungtissue. The total ice ball coverage rate was93.5%. The local progressionobtained by CT scan6months later for group A, B and C was12.6%、15.6%and46.2%respectively. There were significant differences between the threegroups (P<0.05). The total quality life of patients with FACT-G3weeks afterPCT was significantly improved. The score of PWB、 SWB、EWB、FWBincreased than preoperative was16.49%、0.92%、19.21%、10.02%respectively.The1-and2-year overall survival was41.51%and31%, respectively. Themajor complications occurred in15(6.5%) of231patients, which includes5cases of intractable hemoptysis,1case of brachial plexus injury,9cases ofdelayed pneumothorax and3cases of needle track implation. ConclusionMulti-needle combination can significantly improve the efficiency ofcryoablation. Acute lung tissue injury caused by freezing is demonstrated in threedifferent changes. Clinical practice shows that conformal PCT for NSCLC, whichhas simple procedure, fewer complications and less major complications, canrapidly reduce the tumor load and improve quality of life of patients."Target sign"performed intraoperative is a radical frozen image performance in small lesions. Ifthe "Target sign" is incomplete, a combined therapy with traditional radiotherapy,chemotherapy or other local threatments will be considered.