Freezing Fort Knox: Mesenteric Carcinoid Cryoablation

Modern cancer therapy: cryoablation meets immune checkpoint blockade

Cryoablation, as a minimally invasive technology for the treatment of tumors, destroys target tumors with lethal low temperatures. It simultaneously releases a large number of tumor-specific antigens, pro-inflammatory cytokines, and nucleoproteins, known as "danger signals", activating the body's innate and adaptive immune responses. However, tumor cells can promote the inactivation of immune effector cells by reprogramming immune checkpoints, leading to the insufficiency of these antigens to induce an immune response capable of eradicating the tumor. Immune checkpoint blockers rejuvenate exhausted T cells by blocking immune checkpoints that induce programmed death of T cells, and are therefore considered a promising therapeutic strategy to enhance the immune effects of cryoablation. In this review, we provide a detailed explanation of the immunological mechanisms of cryoablation and articulate the theoretical basis and research progress of the treatment of cancer with cryoablation combined with immune checkpoint blockers. Preliminary data indicates that this combined treatment strategy exhibits good synergy and has been proven to be safe and effective.

Inferior Vena Cava Syndrome as a Manifestation of Metastatic Carcinoid Tumor

Small bowel-origin carcinoid tumor is indolent but may metastasize relentlessly to various sites, including the liver. Over the past 9 years, we have treated a 69-year-old woman who has undergone 5 percutaneous liver ablations, 5 hepatic intra-arterial chemoembolizations, an ovarian cryoablation, and a trans-ventral hernia mesenteric cryoablation. These interventions are all related to her inoperable carcinoid malignancy. After the patient presented with swelling of the abdomen and both lower extremities, computed tomography (CT) angiography was performed, revealing a circumferential hepatic metastatic mass encasing the intrahepatic inferior vena cava (IVC) and extensive third spacing of fluids specific to the IVC distribution below the diaphragm. A venogram of the intrahepatic IVC revealed extrinsic compression causing 95% narrowing of the vessel. A balloon was advanced to the level of the lesion and inflated, increasing the caliber of the vessel. Subsequently, 2 covered aortic stent graft cuffs were deployed in an overlapping fashion within the lumen of the IVC, traversing the area of narrowing. Next, an open-cell aortic dissection stent was placed across both overlapping aortic stents from the renal veins to the hepatic veins. Following this, three 17-gauge cryoablation probes were inserted into the segment 1 intrahepatic lesions encasing the newly stented IVC via an anterior percutaneous approach. Two 10-min freeze cycles were performed with intraoperative CT imaging, demonstrating circumferential coverage of the lesions. Posttreatment venogram revealed patent stent grafts within the intrahepatic IVC, and restoration of vessel patency. No immediate postoperative complications were noted. The patient's abdominal and lower extremity swelling resolved completely within 1 week after procedure. Two-month follow-up CT demonstrated markedly decreased size of the metastatic lesions and no adverse effects. Six- and 9-month PET-CT scans demonstrated maintained patency of the IVC stent. This palliative procedure allowed the patient to maintain good performance status and alleviated her symptoms of IVC syndrome. The radial force generated by the multiple aortic stents will ostensibly maintain the patency of the intrahepatic IVC. Cryoablation of the encasing metastatic lesion was performed with markedly decreased size of the tumor on the 2-month follow-up.

Expanding the Frontiers of Treatment: Cryoablation of an Ovarian Mass

The ovaries are a common site of metastasis from a variety of solid organ malignancies. These tumors most commonly originate from the gastrointestinal tract. Neuroendocrine tumors of the small bowel are unrelenting in their tendency to exhibit this type of distant spread, which poses a challenge for curative treatment. Whether metastatic disease to the ovary or primary ovarian malignancy, this is a major cause of morbidity and mortality for women of various ages. Currently, a mainstay of palliative treatment for advanced-stage disease resides in surgical debulking and chemotherapy. At times, these patients may not be surgical candidates due to various reasons which may include a large disease burden. Computed tomography-guided percutaneous cryoablation is a minimally invasive technique that has shown promise in treating solid organ metastatic lesions by exposing them to lethal temperatures. We describe a novel technique of palliative cryoablation of a primary small bowel carcinoid tumor that metastasized to the ovary. Hydrodissection was utilized to create a window for safe percutaneous treatment. At the end of freeze cycles, intraoperative CT was performed, demonstrating greater than 90% incorporation of the ovarian tumor within the margins of the lethal ice zone. Our team decided that this was a maximum percentage of freeze due to neighboring vessels and bowel. The patient tolerated this treatment well, and there were no reported post-operative complications. The procedure was clinically successful at shrinking the tumor as demonstrated on a nine-month follow-up CT. Percutaneous cryoablation is already a widely utilized method for treating tumors in various locations including the kidneys and liver. The application of cryoablation can be expanded as an effective and safe palliative technique for treating ovarian tumors. This may be especially useful in patients that are not surgical candidates.

Rare Treatment for a Rare Tumor: Cryoablation of a Granular Cell Tumor

Background

Granular cell tumors (GCTs) or Abrikossoff's tumors are rare neoplasms known to originate from Schwann cells in the peripheral nervous system. These lesions are usually benign; malignancy only occurs in 1-2% of cases. Surgical resection is the traditional treatment method for GCTs, but it poses several risks and disadvantages related to the surgical incompatibility of the patient, the extended recovery time, and the chance of relapse. Cryoablation is becoming an increasingly favored method of treatment for tumors, both benign and malignant, due to its minimal invasiveness, natural analgesic properties, and ability to stimulate antitumor immunity. Cryoablation may contribute to the prevention of secondary and metastatic tumor growth in cases of malignancy by preserving tumor-associated antigen molecules for recognition by cell-mediated immunity.

Methods

This article describes a novel method for GCT treatment using cryoablation. This technique exposes tumor tissue to extreme cold temperatures, effectively destroying tumor cells by irreversibly compromising their plasma membranes. To our knowledge, this is the first report in the literature of cryoablative techniques being used for GCT.

Results

Cryoablation of this mass was successful with no complications. CT images during the procedure demonstrated circumferential coverage of the entire lesion with no injury to the surrounding tissues.

Conclusion

Cryoablation can be used as an alternative to surgical intervention to treat malignant GCTs. This procedure is minimally invasive, less painful, and potentially effective in promoting antitumor immunity.

Management of Gastrointestinal Neuroendocrine Tumors

Neuroendocrine neoplasms (NENs) are derived from neuroendocrine cell system and can have benign or malignant characteristics. They are rare tumors, but have been increasing in incidence over the past 40 years. Patients with NENs may develop symptoms due to primary tumor invasion, metastasis, or from secretion of hormonally active tumor substances. Multiple imaging modalities are used for diagnosis and staging, including specialty scans such as ¹¹¹In pentetreotide (Octreoscan) and ⁶⁸Gallium-DOTATATE, along with endoscopy, endoscopic ultrasound, and biochemical marker testing. Treatment involves both surgical approach, for both primary and metastatic lesions, as well as medical management for symptom management and disease progression. This article will review the current clinical knowledge regarding the diagnosis, treatment, and prognosis of these fascinating neoplasms and the associated hormonal syndromes.

Finally, a Minimally Invasive Option for Intrahepatic Inferior Vena Cava Invasion by Hepatocellular Carcinoma

Background

Major vessel invasion is a late manifestation of hepatocellular carcinoma, which may directly result in mortality if left untreated. Surgical resection may be an option for select patients; however, surgery may be contraindicated. Contraindications include multifocal disease, poor liver reserve, inability to tolerate surgery, and patient preference. Cryoablation is a minimally invasive therapy utilized for treating hepatic neoplasms by subjecting them to extreme cold temperatures. The "thermal sink" effect describes cryoablation near flowing blood such as that found in high volumes within major vascular structures. Thermodynamics dictates that proximity to the flowing intravascular compartment will decrease ice formation, and therefore, tumor destruction.

Methods

This report describes a novel palliative technique to induce temporary cessation of the blood flow in the intrahepatic inferior vena cava (IVC), thus enabling the operator to perform cryoablation targeting invasive cancer within.

Results

Adequate ablation using this technique allowed a patient with IVC invasion 9 months of survival.

Conclusion

Quality of life during this time was maximized, as recovery time from this procedure is minimal.