Targeted Cryoablation Boosts Survival in Ovarian Cancer

Martha Kerr

January 19, 2012

January 19, 2012 — Multisite cryoablation of metastatic epithelial ovarian cancer is well tolerated, has a 5-year overall survival rate of 30%, and is cost effective, compared with other forms of adjuvant therapy, investigators reported at the Clinical Interventional Oncology 4th Annual Symposium, held in collaboration with the International Symposium on Endovascular Therapy, which is underway in Miami Beach, Florida.

Results from 41 computed-tomography-guided and/or ultrasound-guided percutaneous cryoablation procedures on 48 tumors in 21 patients were presented by Hyun J. Bang, MD, a radiology resident at Wayne State University in Detroit, Michigan. He worked closely with Peter J. Littrup, MD, from the Karmanos Cancer Institute, also in Detroit, where the procedures were performed; Dr. Littrup has more than 20 years of experience in the field of radiology.

Cryoablation sites included retroperitoneal and intraretroperitoneal regions, bone, liver, lung, and superficial sites.

Major complications occurred in 7% of cases (3 of 41 patients), and the local recurrence rate was 2% (1 of the 48 sites treated).

The researchers calculated median overall survival rates, years of life gained with the technique, and costs associated with cryoablation per life-year gained.

The 5-year survival rate was approximately 30% and median survival was 56.9 months. There was an average period of 37.8 months between the diagnosis of metastatic disease and the administration of cryoablation. The average adjuvant cost-effectiveness ratio was estimated at $26,806 per life-year gained.

"Our patient group's median survival falls within the average range of median survivals observed for patients with no residual disease following secondary surgical cytoreduction," Dr. Bang noted in an interview with Medscape Medical News. "However, the greatest distinction between the 2 treatments is that cryoablation was able to completely treat the tumor in 98% of cases, while surgical patients were free of disease in only 43% of cases in 3 recent studies. For the remaining 57% of patients with residual disease, their median survival ranged from 7.2 to 31.1 months, with the amount of residual disease being the strongest factor in survival times. Therefore, cryoablation may be an attractive treatment option for patients presenting with metastases following primary or secondary cytoreduction."

"This treatment is strictly to alleviate symptoms attributed to disease progression in a cost-effective manner," Dr. Bang explained. "Survival benefit is merely a direct effect in the efficacy of cryoablation, which was able to successfully ablate tumors in 98% of cases."

"This treatment is generally given to patients who have already undergone primary cytoreductive efforts and failed sometimes multiple courses of chemotherapy. Our goal is to provide local control of any remaining metastases that may be chemoresistant stem cells, so that subsequent systemic regimens will be more effective," Dr. Bang noted. "At this time, our treatment is aimed at palliation of symptoms; it is not curative."

Therefore, "cost effectiveness is an important factor in selecting treatment options," Dr. Bang said. "As most patients relapse and succumb to their disease, physicians must be vigilant in not placing too significant of an economic burden on the patient or their family. The current projection for cost effectiveness is $100,000 per life-year gained, and our estimated cost of approximately $26,000 dollars per life-year gained falls well within societal limits."

Selection Bias Possible, Says Expert

"While an interesting abstract, it must be stressed that the total number of patients included is extremely limited, and it is not appropriate to make any statement regarding the impact of this strategy on survival," cautioned Maurie Markman, MD, senior vice president of clinical affairs and national director of medical oncology at the Cancer Treatment Centers of America at Eastern Regional Medical Center in Philadelphia, Pennsylvania, in an interview with Medscape Medical News.

"Any observed outcome could very easily reflect bias in the selection of patients who have been included in this series. Considerable additional clinical evaluation must be undertaken to include far larger patient populations before any statement can be made regarding the potential of this approach to be a reasonable alternative to the current standard of care in the management of ovarian cancer," Dr. Markman added.

Cryoablation is often overlooked, "but based on the high survival rate, cost effectiveness, consistent local control, and safety of the procedure, we should be taking a closer look at cryoablation as an option before these women enter the latter stages of their disease," Dr. Bang asserted.

Dr. Bang has disclosed no relevant financial relationships. Dr. Markman is an employee of the Cancer Treatment Centers of America.

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