A Medical Device Daily

A study reported at the 33rd Annual Scientific Meeting of the Society of Interventional Radiology (SIR; Fairfax, Virginia) concludes that cryoablation – the minimally invasive interventional radiology treatment to freeze primary kidney tumors without surgery – is 95% effective when the tumors are 4 cm or smaller and nearly 90% effective for tumors up to 7 cm, when the disease is confined to the kidney at one-year follow-up.

The one-year benchmark is established and well-accepted within the medical community to gauge the success rate of a treatment option because most kidney tumors would be visible at one year with a CAT scan or MRI, according to a statement from SIR.

“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, interventional radiologist at Johns Hopkins Hospital (Baltimore).

When the disease is confined to the kidney, the intent of treatment is curative. Using imaging to pinpoint the tumor, the interventional radiologist inserts a thin probe through the skin and guides it into the tumor below. The probe freezes and kills the tumor during the procedure.

The study showed nearly 95% efficacy for localized tumors up to 4 cm, and nearly 90% efficacy for tumors up to seven centimeters, with the lesions showing as dead tissue (scar) with no recurrences at one-year follow-up imaging.

The ongoing study currently includes approximately 70 lesions in 60 patients with primary renal cell carcinoma.

Of the three patients who failed treatment (5%), one had a 10-cm tumor that physicians did not expect to cure, but there is only 1 cm of residual tumor that they plan to re-treat when the patient returns. The other two failures were in patients with larger tumors (7-10 cm), and physicians plan to treat those two patients again. One has only a half-cm residual tumor 18 months later. Thus, the secondary efficacy (after re-treatment) is expected to be close to 100%.

“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,” said Georgiades.

In addition to the patients who have the smaller tumors, the treatment offers a potentially curative option for patients with localized tumors who are not eligible 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, Georgiades said.

This interventional radiology treatment spares the majority of the healthy kidney tissue and can be repeated if needed.

More than 32,000 Americans each year are diagnosed with kidney cancer, many having shown no symptoms.

In another report from the SIR meeting: The results of a five-year follow-up study of 884 osteoporosis patients bolster the use of vertebroplasty – an interventional radiology treatment for vertebral compression fractures – finding that the procedure provides dramatic pain relief and sustained benefit.

Vertebroplasty, the injection of medical-grade bone cement into a fractured vertebra, shores up the fracture similar to an internal cast and provides pain relief. It is indicated for painful vertebral compression fractures that fail to respond to conventional medical therapy, such as minimal or no pain relief with analgesics or narcotic doses that are intolerable.

The average pre-treatment pain score on the 11-point Visual Analog Scale was 7.9 +/- 1.5, and it dropped significantly to an average of 1.3 +/- 1.8 after the vertebroplasty treatment.

One’s ability to manage everyday life – such as washing, dressing or standing – was measured by the commonly used Oswestry Disability Questionnaire (ODQ), which was completed by patients before – and again one month after–vertebroplasty. The ODQ scores changed from an average of 69.3% +/- 13.5 to 18.8% +/- 6.9, showing a highly significant improvement in mobility.

“These data provide good news for physicians and osteoporosis patients. Many osteoporosis patients with compression fractures are in terrible pain and have a greatly diminished ability to perform basic daily activities, such as dressing themselves,” said Giovanni Anselmetti, MD, interventional radiologist at the Institute for Cancer Research and Treatment (Turin, Italy).

Though the treatment has been shown to improve a patient’s quality of life; it is generally reserved for patients who have failed conventional medical management.

The study also showed that vertebroplasty does not increase the risk of fracture in nearby vertebra. “Vertebroplasty is already known to be a safe and effective treatment for osteoporotic vertebral fractures. Osteoporosis patients remain susceptible to new fractures, which often occur in the contiguous vertebra to an existing fracture. Our large-scale study shows that vertebroplasty does not increase the risk of fracture in the level contiguous to previously treated vertebra and that these new fractures occur at the same rate as they would in osteoporosis patients who did not have vertebroplasty,” Anselmetti said.