Cryoablation is gaining ground in breast cancer treatment and could help reduce morbidity and mortality especially in older patients or those with severe comorbidities, a leading American interventional radiologist told delegates at the Spectrum conference in January in Miami.
Population-based screening for breast cancer has allowed for more patients to be diagnosed with smaller breast tumors, opening up a way for interventional procedures, according to Dr. Yolanda Bryce, Program Director of the Interventional Radiology Residency at the Memorial Sloan Kettering Cancer Center (MSKCC) in New York, and pioneer of breast cancer cryoablation at her institution.
‘People used to have large surgeries, including resection of the pectoralis muscle, and that has evolved into smaller and smaller surgeries,’ she said on the third day of the conference, which gathered 325 medical specialists in interventional oncology. ‘Even how we look at margins has changed. We used to look at five-millimeter margins, now we look for no tumor on ink with invasive cancer and two millimeters with ductal carcinoma in situ.’
The trend for detecting smaller lesions has opened up a door for smaller procedures such as cryoablation, particularly in older patients who have more comorbidities, she explained. ‘Ablation is less invasive than surgery, especially when we’re talking about institutions that are still using general anesthesia for lumpectomy, which can result in significant morbidity and mortality,’ she said.
A multi center phase II clinical trial (ACOSOG z1072) with 87 breast cancer patients that had cryoablation prior to surgery ‘demonstrated that, for tumors that were one-centimeter or less, breast cancer treated with cryoablation was completely eradicated,’ she said.
Further research suggests that larger tumors can also probably be treated with cryoablation with multiple probes (Littrup, et al 2009), especially in patients who are not surgical candidates.
To start offering cryoablation as a treatment for breast cancer, medical teams should probably begin with smaller lesions, Bryce recommended. ‘I would suggest starting with lesions of one to two centimeters of size, at least until you get the process going. It probably shouldn’t be too close to the skin until you get really good at hydrodissection.’
Radiologists should also remember that the entire ice ball needs to be buried. ‘When we do biopsies in breast imaging, we always think about the shortest course to get to the lesion. With cryoablation, you need to think of burying that ice ball. Therefore, sometimes you need to go a longer distance, even on the other side of the breast, depending on how big the breast is, to give yourself enough margin.’
Any cryoablation device available for the procedure is good enough. ‘The equipment I use allows me to form ice balls of different sizes. You just need to know what size you need the ball to be.’
Another important thing to consider is how deep the probe needs to be buried inside the breast. ‘The device I use has little notches on it and I know which notch I need to not see so I know that the ice ball is buried in the breast,’ she said. ‘Very often people worry about the ice ball nearing the surface, but where I‘ve gotten into trouble is when I haven’t placed the probe deep enough in the breast.’
The procedure can be challenging when dealing with tumors that are very close to the skin. ‘Literature recommends five millimeters. My experience is that, as long as the tumor is not attached to the skin, you can obtain a pretty good margin from the ice ball to the skin surface.’
Complications such as burns are part of the procedure and solutions do exist. ‘I used to be afraid of complications, now I just describe them as part of a procedure. If a patient’s breast is burned with the procedure, I will send her home with Silvadene and pain medications’ she said. ‘I deal with a lot of patients who have really big tumors and many are close to the breast. If a burn doesn’t heal with conservative measures, I will contact plastic surgeons if it ever comes to that.’
Remaining issues such as the reliability of imaging, whether it is contrast-enhanced MRI or mammography, and addressing the axilla, need to be tackled as cryoablation gains ground in clinical practice, she concluded.