Imaging, biopsy and cryoablation techniques
Hope Racine, SIR TODAY 2022 | Thursday, July 14
Breast cancer is the most common cancer among American women, aside from skin cancers, and is the leading cause of cancer death for women across the globe. According to Jason P. Shames, MD, MBS, one in eight women in the United States will develop invasive breast cancer—but breast cancer survivorship has tripled over the last 60 years, thanks to advances in imaging and increased screening.
“Mammography is the gold standard for breast cancer screening,” said Dr. Shames, during the “Cryoablation for breast cancer” session at SIR 2022. “But breast cancer can present in various ways.”
Dr. Shames showed imagery to demonstrate presentation, alongside how it can be viewed via supplemental imaging like diagnostic mammography, contrast-enhanced mammography, breast ultrasounds and breast MRIs.
The typical breast ultrasound looks at tissue composition and masses (their shape, orientation, margin, echo pattern and calcifications), as well as special cases like cysts, foreign bodies or fat necrosis. Recognizing and documenting these factors is step 1 in identifying and staging breast cancer.
Understanding the nuances of breast imaging is also crucial, because it allows for more successful biopsies, according to Monica Huang, MD.
“For locoregional staging, ultrasound-guided biopsy expedites and confirms disease diagnosis and extent and may obviate the need for breast MRI,” Dr. Huang said. “For an accurate pathology diagnosis, you have to select the appropriate modality for imaging guidance, biopsy device type and needle size based on imaging morphology and differential diagnosis.”
However, Dr. Huang emphasized that while the radiology–pathology correlation is based on lesion morphology and differential diagnosis, it relies primarily on the accuracy of targeting and the quality of the sample for concordance.
“Was the correct lesion or area in the lesion biopsied? Was the needle within the lesion? Did the sample include the lesion? And was the tissue retrieved sufficient in volume and quality?” she asked.
To demonstrate the importance of targeting accuracy and sample quality, Dr. Huang presented several breast and lymph node biopsy studies, which included instructions on how to identify axillary levels I,II and III as well as internal mammary lymph nodes for breast cancer staging and biopsy under ultrasound. With each example she discussed the biopsy approach, imaging guidance used, needle selection and outcome.
“To ensure quality sample is obtained, needle size is not everything,” she said. “Appropriate biopsy target selection is also important.”
Dr. Huang and Dr. Shames’s presentations on imaging and biopsy guidance set the stage for a look at breast cancer cryoablation. Eisuke Fukuma, MD, PhD, traveled from Japan to present on his 16-year experience with cryoablation. Citing a long history of cryomedicine in Japan, Dr. Fukuma felt that they had to develop an image-guided nonsurgical treatment modality for breast cancer.
According to Dr. Fukuma, cryoablation has multiple advantages over a traditional surgical approach like lumpectomy: the patients have real-time monitoring and same-day surgery with local anesthesia, there is no damage to surrounding tissue and has a good cosmetic outcome, and his team can treat any size breast or location of lesion.
He walked attendees through the principles of cryoablation, as well as his materials and safety margins, detailing how they determine the size of lesions and what size of an ice ball to use.
Though Dr. Fukuma said he can treat patients with any size breast, he follows a strict patient criterion—the cancer must be free from skin and muscle involvement, and candidates have to accept whole breast irradiation and adjuvant treatment according to staging and biology.
“There are expected complications,” he said. “But this is a very good alternative to an invasive, surgical approach.”
Gao-Jun Teng, MD, FSIR, joined from China to present on his own experiences with breast cryoablation. While he has treated a smaller number of patients, the therapy has showed a promising outcome. “The data indicates that this is a safe alternative to surgery, especially for those with early breast cancer who can’t or won’t have surgery,” he said. He also indicated that it may be an option for those with impalpable calcification lesions and triple-negative breast cancer (TNBC).
While cryoablation is becoming more common place in East Asia, trials are still being conducted in the United States. According to Kenneth Tomkovich, MD, while lumpectomy is considered the gold standard treatment, there has not been a widely accepted new approach in almost 20 years.
“IR has pioneered ablation therapies for the liver, kidney and thyroid, but the breast is missing,” he says. “So why isn’t it widely available and practiced?”
The reason, he believes, is that not many IRs have performed this research—and though the limited research within the community is promising, there is a substantial need for more comprehensive studies.
To fill this gap, Dr. Tomkovich serves as one of the lead investigators on the ICE3 trial, the first multicenter large-scale trial to evaluate cryoablation as a primary treatment for breast cancer with no surgical excision. Patients receive only imaging on follow-up, and the investigators have set a goal of no clinical or imaging evidence of residual or recurrent lesions at 5 years post-ablation.
According to Dr. Tomkovich, 194 patients at 19 sites enrolled in the trial, and had 100% procedural success with no serious adverse procedure-related events.
“We have a success rate of 97% to date, with promising long-term results,” he said. “This indicates the cryoablation is feasible, safe and well tolerated. The results are also consistent with the expected recurrence rates of surgical lumpectomies.”
Given these rates, Dr. Tomkovich says he and other investigators feel that cryoablation is effective for stage I, small, low-risk breast cancer.
However, IRs need to know what the “new normal” will look like for those who have undergone cryoablation, in order to read future imaging correctly.
Alexander Sevrukov, MD, another investigator on the ICE3 trial, presented several case studies and imaging examples to show attendees what a patient who underwent cryoablation will look like at the 5-year follow up.
“The results are very similar to those post-lumpectomy,” he said, pointing out that patients will likely have evolving rim calcifications of fat necrosis and a post-procedure halo. He also said that ultrasound after cryoablation should generally be avoided, and patients should be educated that a lump at the site of cryoablation is normal.
“This is not a cause for concern or biopsy, unless mammography finds suspicious recurrence,” he said, before providing examples of what a recurrence or residual tumor would look like.
“The patient may develop asymmetry within or at the edge of the ablation zone,” he said, “and early, fine calcifications of fat necrosis may mimic malignancy.”
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