Kidney tumor ablation, specifically cryoablation, has emerged as a minimally invasive alternative to traditional surgical treatments like nephrectomy. As a relatively novel approach, it’s essential to understand the indications, risks, benefits, and outcomes of cryoablation for kidney tumor management. In this article, we will explore these aspects and compare cryoablation to the more conventional nephrectomy procedure.
Intro to Renal Cell Carcinoma
Renal cell carcinoma (RCC) ranks third in the world in terms of morbidity among malignant neoplasms of the genitourinary system after tumors of the prostate and bladder. In terms of the growth rate of cancer incidence in North America, RCC steadily ranks second after prostate cancer. Every year, in the United States more than 65,000 men and women get kidney cancers, and about 14,000 men and women die from this diseases.
The widespread introduction of modern diagnostic methods has led to an increase in the detection rate of early-stage RCC. Currently, there is a decrease in the size of the primary detected kidney tumors with an increase in the proportion of T1 or low grade tumors and a decrease in the proportion of advanced RCC because of early detection and treatments. The number of patients with a tumor <4 cm in diameter has steadily increased. These trends undoubtedly led to an improvement in survival rates in these groups of RCC .
In connection with the migration of the stage of the tumor process towards localized RCC with a small tumor, new organ-sparing methods of treating RCC have been developed in the last two decades, such as laparoscopic kidney resection and most impressively ablative minimally invasive techniques such as cryoablation and microwave ablation both of which are done at LA Vascular.
The essence of a relatively new minimally invasive direction in oncourology consists in the local destruction of the tumor process, when energy is supplied to the lesion, leading to damage (ablation) of the affected area. These technologies are collectively called ablative techniques. Modern ablative approaches include both hyperthermal (radiofrequency ablation – RFA or newer microwave techniques) and hypothermal (cryoablation) methods which have the largest amount of supportive clinical data.
Ablative techniques destroy tumor tissue in situ (within the body) without requiring removal (surgical resection of the mass). Their main potential advantages include low complication rates, no hospital stay, earlier return to normal life, as well as preservation of parenchyma and renal function, lower cost of treatment and the possibility of treating patients with severe comorbidities who may not be candidates for surgery
Cryoablation: An Overview
Cryoablation is a minimally invasive treatment that uses extreme cold to destroy targeted tissue, such as kidney tumors. This procedure involves the insertion of a cryoprobe into the tumor under image guidance (typically CT or ultrasound). The cryoprobe then cools the surrounding tissue, forming an iceball that destroys the tumor cells.
Indications for Kidney Tumor Cryoablation
Cryoablation is typically indicated for patients with:
- Small renal masses (usually less than 4 cm in size)
- Localized tumors without evidence of metastasis
- Poor surgical candidates due to medical comorbidities or advanced age
- Solitary kidneys or a risk of future kidney function decline
Risks and Benefits of Kidney Tumor Cryoablation
- Minimally invasive: Cryoablation is less invasive than nephrectomy, resulting in reduced pain, blood loss, and hospital stay.
- Preservation of kidney function: Unlike nephrectomy, cryoablation can target tumors while preserving more healthy kidney tissue, reducing the risk of future kidney function decline.
- Faster recovery: The minimally invasive nature of cryoablation allows for quicker recovery times compared to traditional surgery.
- Repeated treatment option: Cryoablation can be repeated if necessary, offering additional treatment flexibility.
- Incomplete tumor destruction: There’s a possibility that cryoablation may not completely destroy the tumor, necessitating additional treatment.
- Complications: Though rare, cryoablation can cause complications such as infection, bleeding, or injury to surrounding organs.
- Local recurrence: There’s a slightly higher risk of local tumor recurrence with cryoablation compared to nephrectomy.
Cryoablation Outcomes vs. Nephrectomy
When comparing cryoablation to nephrectomy, it’s essential to consider both short- and long-term outcomes:
- Short-term outcomes: Cryoablation has been associated with shorter hospital stays, reduced pain, and quicker recovery times compared to nephrectomy.
- Long-term outcomes: While nephrectomy has been the gold standard for kidney tumor management, recent studies suggest that cryoablation offers comparable cancer-specific survival rates for small, localized tumors. However, nephrectomy may be associated with lower local recurrence rates.
- Preservation of kidney function: Cryoablation is often better at preserving kidney function compared to nephrectomy, as it allows for more targeted tumor removal while sparing healthy tissue.
Cryoablation is a promising alternative to nephrectomy for select patients with kidney tumors, offering a minimally invasive approach with favorable short-term outcomes and kidney function preservation. While it may be associated with slightly higher local recurrence rates, cryoablation has shown comparable cancer-specific survival rates for small, localized tumors. As with any medical procedure, it’s crucial to consult with a healthcare professional to determine the most appropriate treatment option for individual needs.
More info about Ablation
Cryoablation which is the method with the highest amount of research backing it causes destruction of the tumor by applying temperatures above below -20° C through needle. Alternatively RFA technique which is an older methodology is based on the conversion of radio frequency energy into tissue heating and subsequent coagulation necrosis. High-frequency radiation emanating from the needle electrode causes the excitation of ions and heating of tissues due to molecular friction, which leads to denaturation of proteins and destruction of cell membranes. These changes occur in 4-6 minutes. at temperatures> 50 ° C or immediately at temperatures> 60 ° C. Temperatures> 105 ° C cause tissue boiling and carbonization with the formation of gas bubbles and a decrease in the effectiveness of RFA for the formation of a larger focus of coagulation necrosis. The main purpose of RFA is to bring a temperature of 50–100 ° C to the entire volume of tumor tissue. The size of the coagulation necrosis zone depends on the impedance of the tissue, the time of RFA, the amount of supplied energy, and the surface area of the RFA electrodes. Exophytic tumors surrounded by avascular perirenal adipose tissue are more desirable for ablative techniques especially compared to central tumors surrounded by well-perfused, vascularized parenchyma, which acts as a heat and cold dissipating radiator.
Ablation can be performed using open, laparoscopic and percutaneous approaches. Percutanous approach is the method of choice in most cases as it is truly minimally invasive with shorter recovery times . Ablation using laparoscopic access has a number of other advantages, such as tumor mobilization, prevention of damage to adjacent organs and structures if they cannot be moved by other methods, and placement of RFA electrodes under visual control. Most of these advantages of ablation performed by laparoscopic methods can be abated with percutaneous ablation is performed by experienced hands as nearby structures can be moved with hydrodissection of air dissection where air and fluid are introduced between the mass and the critical structure so as to avoid injury to the other structures. Additionally as visualization with ultrasound and CT has improved percutaneous methods have become more popular.
Currently, ablation with percutaneous access, which can be performed on an outpatient basis, is more common. Ablation electrodes can be placed under ultrasound, CT and MRI guidance. The effectiveness of ablation can be assessed no earlier than after 1 month. after the manipulation, while according to the results of CT examination, the ablated tumor tissue should not take up a contrast agent.
The main indication for performing ablation of a kidney tumor is a well-visualized tumor under imaging and a mass measuring less than 4 cm in diameter, localized along the periphery of the kidney. Ablation can be performed in most patients with small kidney tumors. In particular, the use of ablation of kidney tumors is recommended for use in elderly patients with concomitant pathology (arterial hypertension, diabetes mellitus, kidney stones, renal failure, cardiovascular diseases, including a history of myocardial infarction). It is also permissible to use cryoablation in patients with a single kidney and in the presence of hereditary diseases (von Hippel-Lindau disease, tuberous sclerosis, hereditary papillary RCC)
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