Interventional Radiology is a rapidly developing and growing branch of medicine. The techniques of Interventional Radiology are used for many different types of cancers at different stages of the disease. These treatments are grouped together because they are all done by Interventional Radiologists using image guidance such as Xray, ultrasound or CT scans. The procedures are all minimally invasive (keyhole) usually done using local anaesthetic and sometimes stronger pain killers and sedatives.
Many of these minimally invasive procedures are mentioned on other pages on this website, but are grouped together on this page to help put them into context.
Although scans can often give a good idea of what sort of cancer is causing the patient’s symptoms, a needle biopsy is often required to diagnose a specific type of cancer. This is because cancer treatments are becoming more and more specific to each type of cancer. A needle biopsy involves the interventional radiologist scanning the patient, usually with an ultrasound scanner or CT scanner, and finding a safe path through the skin into the tumour.
Local anaesthetic is used to numb the skin and sometimes sedation can be given too. A small amount of the cancer tissue is removed on the end of the needle and placed onto a slide. The slide is prepared and then looked at by another specialist, the pathologist, to diagnose whether the tissue is cancer or not, and if so then what sort it is. That process usually takes at least one week. This information is then sent back to the specialist doctor primarily responsible for your care.
Relief of Obstructions
Sometimes cancers can grow inside the body and cause blockages of important tubes or ducts, for example the ureter, which is the tube that connects the kidney to the bladder. Interventional radiologists have many techniques using small tubes (catheters) and guidewires which allow them to reach these important structures inside the body through small cuts in the skin. They can leave a temporary plastic tube inside the blocked structure to allow the fluid (eg urine or bile) to flow either out into a bag, or sometimes inside past the cancer causing the blockage.
Sometimes more permanent metal mesh cylinders (called “stents”) can be left inside for a long term solution to the problem. Another example like this is for cancers which block the colon – interventional radiologists will help the surgeon place a stent across the cancer to open up the colon and prevent the patient from becoming very ill because of complete blockage of the bowel (colonic stent).
Another example like this is the ability to place a feeding tube through the skin into the stomach for patients whose gullet has been blocked by a cancer in their throat. This allows the patient to get nutrition straight into their stomach, sometimes to build them up before surgery. That is called a gastrostomy tube.
Interventional Radiologists can direct special needles or probes through the skin directly into cancer cells in parts of the body such as liver, kidney, lung and bone. The needle is directed into the correct part of the body using an ultrasound or CT scanner. These procedures can be done with the patient under full general anaesthetic or using local anaesthetic and drugs injected into a vein to cause sedation. When the probe has been positioned in the middle of the cancer then it is connected to a special generator that causes the tip of the probe to heat up, and to heat the cancer cells up to more than 60 degrees centigrade which causes these cells to die.
This treatment is suitable for a relatively small number of patients as the cancers deposits usually need to be quite small and few in number. There are several types of tumour ablation, but the most common are radiofrequency ablation or microwave ablation. Another new type of ablation called irreversible electroporation is not currently available in Northern Ireland, as it is in very early stages of research to find out whether it is an improvement on more conventional ablation. Tumour ablation is often used to slow down cancer growth and sometimes can kill the cancer completely.
This is a treatment most often used to slow down different types of liver cancers. The interventional radiologist passes a small tube (catheter) into the main artery in the patient’s groin, and then is able to direct it up through the main blood vessels in the body and then into the artery that supplies the liver. When it is in the right place a special mixture of tiny plastic particles with a chemotherapy drug bonded onto them is injected into that artery. These tiny particles then flow in the blood into the liver cancer cells and release the drug straight into the cancer cells. This means that the cancer cells are exposed to a higher concentration of the chemotherapy drug.
It is also possible to bond a special radioactive material (Yttrium) onto these tiny plastic particles which when released from the catheter get stuck in the tiny blood vessels inside the cancer. The radiation then goes straight into the cancer. This is a highly specialised and expensive procedure only suitable for a small number of patients. It is called radioembolisation.
That is a summary of the developing part of medicine called Interventional Radiology. These techniques are almost always alongside other better known treatments, but used together can often result in better care for the cancer patient.