April 7 , 2008
Reporter’s Notebook: SIR 2008
Vol. 9 No.7 P. 14
Editor’s note: This feature is compiled from information provided by the Society of Interventional Radiology (SIR) media relations staff for the organization’s 33rd annual scientific meeting held March 15 to 20 in Washington, D.C.
RFA Study: Prolonging the Lives of Patients With Inoperable Lung Cancer
Radiofrequency ablation (RFA) greatly improves survival time from primary or metastatic inoperable lung tumors, according to a study released at SIR’s 33rd annual scientific meeting held last month in Washington, D.C.
“About two thirds of patients diagnosed with non–small-cell lung cancer [NSCLC] are ineligible for surgery and typically have less than 12 months to live. A subset of these patients ineligible for surgery can be treated with RFA with the intention of curing the primary tumor,” said Thierry de Baere, MD, an interventional radiologist with the Institut Gustave Roussy in Villejuif, France. “Thus, 70% of my patients gained at least another two years. This new outpatient treatment is effective, allowing us to treat patients who historically have only palliative options such as chemotherapy or radiation therapy.”
During the procedure, the physician inserts a small needle through the skin into the tumor, generally guided by CT. Radiofrequency energy is transmitted to the tip of the needle where it produces heat in the tissues. The dead tumor tissue shrinks and slowly forms a scar. At the same time, heat from radiofrequency energy closes small blood vessels and lessens the risk of bleeding. RFA usually causes little discomfort, and the procedure is FDA approved for the treatment of tumors in soft tissue, including the lung.
Of the 244 study patients suffering from lung metastases (195 patients) or primary NSCLC (49 patients), 70% were still alive at two years, including 72% with lung metastases and 64% with primary lung cancer. These survival results are similar to surgical results from other studies, but the interventional treatment is less invasive with far fewer side effects and less recovery time. The researchers found that RFA can often destroy the primary tumor and, therefore, extend a patient’s survival and greatly improve his or her quality of life. Survival thus becomes dependent on the extent of disease elsewhere in the body.
Of the 49 patients aged 27 to 85 with primary NSCLC who were treated with RFA, 85% had no viable lung tumors when imaged after one year, and 77% had no viable lung tumors after two years, which indicates a cure. This study was conducted in tumors that were 4 centimeters in diameter or smaller. Better results were obtained for tumors smaller than 2 centimeters. These results are similar to studies in the United States and add to the growing body of evidence for RFA in extending survival time.
The lung is the most common site for primary cancer, and smoking tobacco is the leading risk factor. Last year, the American Cancer Society estimated that approximately 213,380 new cases of lung cancer were diagnosed in this country, accounting for 15% of all new cancer cases.
RFA is effective for local control of lung cancer, providing an attractive option for patients who may not be ideal surgical candidates, who wish to avoid conventional surgery, or who have failed conventional treatments. More research is needed to define whether RFA can replace surgery in a subset of patients.
By the time lung cancer becomes symptomatic, 85% of patients are incurable, often due to serious coexisting health conditions or poor respiratory function. Most patients who are diagnosed with NSCLC are not surgical candidates at the time of diagnosis. For these patients, minimally invasive interventional radiology procedures can improve survival, reduce pain, and improve quality of life. Interventional radiologists are uniquely skilled in using imaging guidance to deliver targeted cancer treatments throughout the body.
Radiofrequency energy can be delivered without affecting a patient’s overall health, and most people can resume their usual activities in a few days. It is a safe, minimally invasive tool for local pulmonary tumor control with negligible mortality, little morbidity, short hospital stay, and positive gain in quality of life. RFA can also be repeated if necessary or combined with other treatment options.
Lung function is generally better preserved after RFA than after the surgical removal of a tumor, which is especially important to patients whose breathing ability is impaired, such as current or former cigarette smokers.
Age Not a Limit for Arterial Interventions
Patients over the age of 80 can safely undergo diagnostic angiography and arterial interventions such as vascular stenting and angioplasty and do just as well as younger patients. A study released at SIR’s annual scientific meeting indicated that patients between the ages of 85 and 93 tolerated these procedures well, avoided surgery, and could be treated as outpatients, irrespective of age.
“This is important news for seniors and their doctors,” said George G. Hartnell, FRCP, FRCR, chief of cardiovascular and interventional radiology at Baystate Medical Center in Springfield, Mass. “In some cases, doctors may be reluctant to send an older person for treatment. There’s no reason for seniors with leg pain caused by peripheral arterial disease [PAD] to put up with pain, limited mobility, and diminished quality of life. Likewise, treating blocked renal arteries can improve kidney function and treat high blood pressure if caused by diminished renal blood flow.”
The outcomes of the treatments in the octogenarians were compared with those of patients aged 50 to 79 who had an equivalent procedure during the same time period by the same doctor. The study included 64 octogenarians who had arterial angioplasty and/or stenting to treat PAD caused by blocked arteries in the legs or to improve blood flow to the kidneys by opening blocked arteries that deliver blood to them. All patients were treated as outpatients and followed after discharge from the hospital.
“What is an appropriate treatment at 55 is just as safe and appropriate at 85,” Hartnell said. “Older seniors can be treated as outpatients, and age did not increase the risk. This is very relevant because the incidence of clogged arteries increases with age, and peripheral arterial disease affects 12% to 20% of Americans age 65 and older.”
Drug Delivery Via Catheter Saves Frostbitten Limbs
Using imaging to visualize areas lacking blood flow and deliver drugs via catheter, interventional radiologists are reopening recently frozen, clotted arteries with clot-busting and antispasmodic drugs to treat patients with severely frostbitten hands and feet, according to a study released at SIR’s annual scientific meeting.
“Previously, severe frostbite was a one-way route to limb loss,” said George R. Edmonson, MD, an interventional radiologist with St. Paul Radiology in Minnesota. “This treatment is a significant improvement. We’re opening arteries that are blocked so that tissues can heal and limbs can be salvaged. We were able to reopen even the smallest arteries, saving patients’ fingers and toes.”
Severe frostbite cases with tissue frozen to the bone and damage occurring deep in muscles, tendons, nerves, and blood vessels typically leads to gangrene and loss of limbs. In severe frostbite, the blood vessels are affected, and blood flow is blocked. After thawing and rewarming, small clots form. Spasm of the injured arteries further impedes flow to the smallest vessels in the limbs. The standard treatment for frostbite, typically involving rewarming the affected area and, in severe cases, amputation, hasn’t changed for decades.
Interventionalists using angiography to confirm loss of blood flow to a patient’s hand or toes and then intra-arterial catheters to directly deliver drugs to dissolve the blood clots and relax the arteries’ muscular walls are finding the technique successful in preventing amputation and saving limbs.
According to Edmonson, severe frostbite, or “freezeburn,” looks like a second-degree heat burn with large blisters, but it’s actually body tissue that’s been frozen and, in severe cases, is dead. “For half our patients who received the clot-busting drug Tenectaplase, this technique worked beautifully, saving all fingers, hands, toes, and feet that otherwise would have been lost,” said Edmonson, who has been treating an average of six to 10 frostbite patients each year for the past 10 years. “Overall, in about 80% of the cases, it significantly improved patients’ outcomes. Within one to three days of treatment, we saw improvement,” noted Edmonson, explaining that patients were followed for six weeks to assess their final outcomes.
In this small prospective trial, results from six frostbite patients aged 18 to 65 who received Tenectaplase were compared with 11 individuals who had received Retaplase. The trial was designed to see if the greater plasma stability of Tenectaplase would lead to better results. “With both groups, approximately 80% of the patients’ affected limbs, fingers, and toes responded with significant improvement. The treatment has been demonstrated to be safe and beneficial. We will continue research to improve and modify the protocols,” noted Edmonson.
Freezing Can Cure Small, Localized Kidney Tumors
Cryoablation surgery is 95% effective when kidney tumors are 4 centimeters or smaller and nearly 90% effective for tumors up to 7 centimeters when the disease is confined to the kidney at one-year follow-up, according to research presented at SIR’s annual meeting last month.
“This interventional radiology treatment can effectively kill localized kidney tumors on an outpatient basis for most patients while offering a fast recovery time and an excellent safety profile,” said Christos Georgiades, MD, PhD, an interventional radiologist at Johns Hopkins Hospital in Baltimore. When the disease is confined to the kidney, the intent of treatment is curative.
The ongoing study includes approximately 70 lesions in 60 patients with primary renal cell carcinoma (RCC). Of the three patients who failed treatment (5%), one had a 10-centimeter tumor that physicians did not expect to cure, but there is only 1 centimeter of residual tumor that they plan to re-treat when the patient returns. The other two failures were in patients with larger tumors (7 to 10 centimeters), and physicians plan to re-treat those patients as well. One has only a half-centimeter residual tumor 18 months later. Thus, the secondary efficacy (after retreatment) is expected to be close to 100%.
The most common type of kidney cancer is RCC, which forms in the lining of the renal tubules in the kidney that filter the blood and produce urine. Approximately 85% of kidney tumors are RCCs.
“The current gold standard treatment is laparoscopic partial nephrectomy surgery but given the high success of interventional cryoablation, that may change. We expect that the two treatments will be shown to be equivalent in a comparative study that is ongoing now at Johns Hopkins. The interventional radiology treatment is less invasive and easier on the patient,” noted Georgiades.
In addition to the patients who have the smaller tumors, this treatment offers a potentially curative option for patients with localized tumors who are ineligible for surgery. Many patients have other diseases that make surgery very high risk, cannot undergo the anesthesia, and do not have any other option. Also, people with borderline kidney function, only one kidney, or multiple recurring tumors had no options until now, he explained.
“I want to get a message out, mostly to my colleagues, because they will encounter many patients who have these treatable cancers, but they cannot have treatment or surgery because of other diseases,” Georgiades said. “Until a few years ago, we in the medical community simply followed these patients; we didn’t treat the cancer for fear we may make things worse if we try to treat risky patients. But for many patients that’s no longer the case.”
This interventional radiology treatment spares the majority of the healthy kidney tissue and can be repeated if needed. The treatment is safe, and most patients are sent home the day of the procedure while the rest go home the next day. The most common complication is a bruise around the kidney that eventually goes away.
The study from the Barbara Ann Karmanos Cancer Institute in Detroit involved 65 people and 81 masses, of which 61 were primary RCC, six oncocytoma, one angiomyolipoma, eight benign or inflammatory renal lesions, and one metastatic lesion. The average tumor size in this study was 2.8 centimeters. At 1.3 years average follow-up (range of 0.2 to 5 years), the majority of tumors continue to image as dead tissue. In contrast to heat, the cryoablation zone continues to shrink after cryotherapy, reducing up to 90% in volume by 12 months without scarring or strictures. Only 6% (five of 81 tumors) had a local tumor recurrence, and these were limited to patients with multiple tumors in the kidney or an early probe failure.
The researchers note it is crucial to use enough cryoprobes to get sufficiently cold temperatures to kill all tumors and extend the visible ice approximately 1 centimeter beyond all tumor margins, similar to a surgical margin. Complications are avoided by the liberal use of saline to push away the adjacent bowel, allowing tumors in nearly any location of the kidney to be treated.
“This interventional treatment is not a widely known procedure yet, even to other physicians, and patients are going to have to pursue it on their own,” added Georgiades. The FDA has approved cryoablation for use in soft tissue tumors, of which RCC is one.