Pleural tumor seeding following percutaneous cryoablation of hepatocellular carcinoma

Advances in Image-Guided Ablation Therapies for Solid Tumors

Image-guided solid tumor ablation methods have significantly advanced in their capability to target primary and metastatic tumors. These techniques involve noninvasive or percutaneous insertion of applicators to induce thermal, electrochemical, or mechanical stress on malignant tissue to cause tissue destruction and apoptosis of the tumor margins. Ablation offers substantially lower risks compared to traditional methods. Benefits include shorter recovery periods, reduced bleeding, and greater preservation of organ parenchyma compared to surgical intervention. Due to the reduced morbidity and mortality, image-guided tumor ablation offers new opportunities for treatment in cancer patients who are not candidates for resection. Currently, image-guided ablation techniques are utilized for treating primary and metastatic tumors in various organs with both curative and palliative intent, including the liver, pancreas, kidneys, thyroid, parathyroid, prostate, lung, breast, bone, and soft tissue. The invention of new equipment and techniques is expanding the criteria of eligible patients for therapy, as now larger and more high-risk tumors near critical structures can be ablated. This article provides an overview of the different imaging modalities, noninvasive, and percutaneous ablation techniques available and discusses their applications and associated complications across various organs.

Incidence and clinical sequelae of portal and hepatic venous thrombosis following percutaneous cryoablation of liver tumors

PURPOSE

To assess the incidence and sequelae of portal and hepatic venous thrombosis after percutaneous cryoablation of hepatic tumors.

METHODS

From November 1998 through December 2010, 223 hepatic tumors were cryoablated during 170 ablation procedures in 135 patients. 24-h post-procedure MR images were reviewed retrospectively by two abdominal radiologists in consensus to identify tumor ablations that developed one or more new portal or hepatic venous thromboses in or outside the ablation zone. On follow-up MRI and CT examinations the outcomes of thromboses were classified as resolved, partially recanalized, persistent, or propagated.

RESULTS

Venous thrombosis developed in association with 54 (24%) of 223 tumor ablations treated during 53 (31%) ablation procedures in 39 (28.8%) patients (15 women, 24 men; age range 40-82 years, mean 59 years). Of these 54 thromboses, 49 (91%) were located in portal vein branches, four (7%) in both portal and hepatic vein branches, and one (2%) in a hepatic vein branch. Thrombosed veins were outside but abutted the ablation zone in 36 (66.7%), and within it in 18 (33.3%). On follow-up imaging (n = 49), thrombi resolved in 29 (59%), partially recanalized in two (4%), persisted in 18 (37%) and propagated from sub-segmental or segmental branches to the left or right portal branches in five (10%). No thrombus propagated to the main portal vein or inferior vena cava.

CONCLUSION

Portal and hepatic vein branch thromboses are common in small branches following percutaneous cryoablation of hepatic tumors and most resolve spontaneously without sequelae.

Percutaneous Cryoablation for Liver Cancer

Based on the primary tumor site, liver cancer can be divided into two categories: (1) primary liver cancer and (2) metastatic cancer to the liver from a distant primary site. Guided cryoablation via many imaging methods induces iceball formation and tumor necrosisand is an attractive option for treating unresectable hepatocellular carcinoma (HCC) and metastatic liver cancer. There are several advantages to using cryoablation for the treatment of liver cancer: it can be performed percutaneously, intraoperatively, and laparoscopically; iceball formation can be monitored; it has little impact on nearby large blood vessels; and it induces a cryo-immunological response in situ. Clinically, primary research has shown that percutaneous cryoablation of liver cancer is relatively safe and efficient, and it can be combined with other methods, such as radiation therapy, chemotherapy, and immunology, to control disease. Although research is preliminary, cryosurgery is fast becoming an alternative treatment method for HCC or liver tumors. Here, we review the mechanisms of liver tumor cryoablation, cryoablation program selection, clinical efficiency, and complications following treatment.

Risk of tumor cell seeding through biopsy and aspiration cytology

Cancer cells, besides reproducing uncontrollably, lose cohesiveness and orderliness of normal tissue, invade and get detached from the primary tumor to travel and set up colonies elsewhere. Dislodging neoplastically altered cells from a tumor during biopsy or surgical intervention or during simple procedure like needle aspiration is a possibility because they lack cohesiveness, and they attain the capacity to migrate and colonize. Considering the fact that, every tumor cell, is bathed in interstitial fluid, which drains into the lymphatic system and has an individualized arterial blood supply and venous drainage like any other normal cell in our body, inserting a needle or a knife into a tumor, there is a jeopardy of dislodging a loose tumor cell into either the circulation or into the tissue fluid. Tumor cells are easier to dislodge due to lower cell-to-cell adhesion. This theory with the possibility of seeding of tumor cells is supported by several case studies that have shown that after diagnostic biopsy of a tumor, many patients developed cancer at multiple sites and showed the presence of circulating cancer cells in the blood stream on examination. In this review, we evaluate the risk of exposure to seeding of tumor cells by biopsy and aspiration cytology and provide some suggested practices to prevent tumor cell seeding.