Medical Device Daily Contributing Writer
LAS VEGAS, Nevada — For 35% of women who will be diagnosed with breast cancer this year in the U.S., they now have a choice of excising the tumor or killing it with a tiny needle and letting the body remove the dead cells naturally. This was one topic of leading edge research presented here at the 19th annual Interdisciplinary Breast Center Conference of the National Consortium of Breast Care Centers (Warsaw, Indiana).
More than 900 breast care specialists including breast surgeons, radiologists, nurses, navigators, and administrators gathered here to share the latest advances in a multiple modality approach to optimal patient care; collecting instructions for the entire breast care team to learn how radiology, surgery, and pathology all correlate with each other when introducing new techniques.
The evolution in the way breast cancer is diagnosed and treated over recent years is remarkable; going from imaging by mammography alone to MRI, PET and ultrasound; from radical mastectomies and full breast irradiation to breast conservation and partial breast brachytherapy; and, in the near future, to ablation in situ of the cancer lesion.
According to the American Cancer Society (Atlanta), an estimated 178,480 new cases of invasive breast cancer occurred in U.S. women during 2008. In addition, approximately another 52,725 new cases of ductal carcinoma were predicted.
The goal of treating these breast cancers is to completely remove all cancer cells while preserving the most cosmetic appearance. To this end, the industry has shifted from radical mastectomies to breast-conserving lumpectomies and now there was even talks on ablating the tumor inside the breast with little, if any, invasion of the breast.
Cary Kaufman, MD, medical director of Bellingham Breast Center (Bellingham, Washington), presented "Moving Beyond Excision: Ablative Technologies for Breast Cancer," discussing the variety of ablative energies thermal, laser, chemical all of which are capable of killing cancer cells.
"Once destroyed, the dead cells are resorbed in a similar fashion regardless of the type of ablation technique used," Kaufman said, "leaving the necrosed tumor inside the breast for the body to eliminate in its natural way." He pointed out that in 2001 the FDA cleared cryotherapy as a modality to treat benign tumors in the breast (fibroadenomas) in situ and in 2002 cleared the path to treat malignant tumors using thermal energy.
In 2004, Sanarus (Pleasanton, California) started a registry for minimally invasive cryoablation of fibroadenomas. The candidates were required to have a single, uniform lesion of less than 3 cm, confirmed by histology, and visible by ultrasound.
In the procedure, a probe is introduced into the breast and then using liquid Nitrogen, forms an iceball around and including the lesion, killing the pathogenic tissue. The patients were followed for 12 months and the results showed that all lesions under 1 cm were totally ablated. Unfortunately, complete ablation of all tumors was only registered at 85%, with popular belief that the 15% had satellite lesions that went undetected prior to cryotherapy.
Ongoing studies now require pre- and post-op MRI films to be performed in addition to the ultrasound so as not to miss any satellite lesions prior to the cryotherapy.
Experimentation with radio frequency (RF) to heat the lesion has also been performed but requires the patient to be in an OR with anesthesia, since "freezing numbs but heat hurts," Kaufman said.
Since both cryoablation and laser ablation can be performed in an office setting without anesthesia, those modalities have taken preference over the use of RF energy in advancing the less-invasive techniques.
Laser ablation introduces a fiber tip percutaneously and then heats the targeted tissue to 60 degrees, killing the cancerous cells. "What may end up being the best of the ablation techniques is that of focused ultrasound, where the patient isn't touched at all," Kaufman argued. "It is the only in situ ablation method that is transcutaneous and under MRI imaging uses high-intensity focused ultrasound to heat and destroy pathogenic tissue rapidly."
InSightec (Dallas), an offshoot of GE Healthcare (Chalfont St. Giles, UK), developed this equipment and is currently studying its use in breast cancer as well as other cancers. "The beauty of this technology and also part of its high cost is the fact that it utilizes MRI imaging," Kaufman said. "The failures we see in in situ ablation techniques are failures of imaging not failures of the ablation."
He added, "The remaining obstacle for in situ ablation is that of being able to truly confirm through imaging that we are dealing with a unifocal tumor. Small doesn't imply unifocal. Only about 35% to 40% of breast cancers are unifocal and thus candidates for in situ ablation."
Another novel form of in situ ablation, developed by Medifocus (Columbia, Maryland), was presented in a poster "A Protocol for Focused Microwave Thermotherapy in Combination with Neoadjuvant Chemotherapy," where the authors Hernan Vargas, MD, of Harbor-UCLA Medical Center (Torrance, California) and others described a method that used adaptive phased array focused microwave thermotherapy to reduce the size of tumors intact in the breast.
The hypothesis was to see if by using focused microwave thermotherapy in conjunction with standard neoadjuvent chemotherapy, they could further reduce the size of the tumor and thereby increase the percentage of patients who would be eligible for breast conserving surgery as opposed to mastectomy.
Based on previous studies that had shown neoadjuvant chemotherapy only provides 30% to 70% conversion from mastectomy, and has a very low rate of complete pathologic response, the researchers wanted to prove that thermotherapy is synergistic with chemotherapy in improving tumor response with the goal of obtaining a higher conversion rate from mastectomy to breast-conserving surgery.
In a small randomized study, they were able to demonstrate increased tumor shrinkage as opposed to neoadjuvant therapy alone, and now have a larger clinical trial planned.
Well over 100 attendees of the conference got up by 6a.m. to attend an early morning breakfast symposium that was sponsored by privately held Novian Health (Chicago), currently the leading company in in situ ablation of breast tumors.
Novian utilizes its proprietary interstitial laser, the Novilase, developed by Kambiz Dowlat, MD, professor of surgery at Rush University Medical Center (also Chicago), to ablate both benign and malignant tumors in the breast.
Cleared by the FDA in 2002, Novian has used the Novilase system in 63 patients, performing 70 procedures; of which 65 were malignant and five were benign. The procedure takes 20 minutes in an office setting with no anesthesia other than a local for the insertion of the fiber optic. Using a 14-gauge needle guided by either stereo or ultrasound, the laser creates a thermal sphere of up to 3 cm created around the tumor that coagulates all pathogenic cells.
Dowlat's presentation "Advances in Laser Ablation of Breast Tumors" encapsulated his 20 years of breast cancer research (see Table 1), culminating with his current use of the Novilase to ablate tumors in situ (see Table 2).
The Novilase laser uses low power that actually heats the tissue as opposed to high power lasers that usually cut tissue. To offset the initial capital expense of purchasing a laser, Novilase will be offering the system on a per-use basis, at a fee that will be competitive with current lumpectomy procedures.
"Only certain patients will qualify for the procedure, as only specific tumor types are amenable to ablation, Dowlat said. "For benign tumors, they must be clearly visualized fibroadenomas or papillomas that are 2 cm or less. For malignant tumors, they must be clearly visualized, invasive, and confirmed by biopsy. Follow-up will include MRIs to detect residual or late recurrence, as well as color doppler ultrasound to detect blood flow that may indicate recurrence."
"Although in its infancy, it appears as though 'We have come a long way, Baby'," said Barbara Schwartzberg, MD, of Rose Medical Center (Denver), who closed this morning session. "To think that only a couple of decades ago we were performing radical mastectomies and now we are investigating ablating the tumor without even touching the patient."
She added: "Ablation of breast tumors could be as big as when surgery moved to minimally invasive procedures such as when lap choly became the standard of care, or when biopsies of sentinal nodes became the norm. This will be a patient-driven procedure and we should all understand who would be eligible."