New Options for Radiation Delivery in Breast Conserving Therapy
Aesthetics, accuracy and confidence—key factors in treating breast cancer for either a patient or a radiation oncologist. When choosing Breast Conserving Therapy(BCT) as their course of therapy, for most women, the goal of breast cancer treatment is not just survival, but preserving as much of the natural breast as possible, so high dose rate (HDR) breast brachytherapy using AccuBoost has become an increasingly attractive treatment option.
InterCommunity Cancer Institute (ICCI) in Clermont, FL has been offering the AccuBoost treatment in conjunction with External Beam Therapy (the proven “Gold Standard”) now for 2 years and has been very pleased with the clinical results.
Under the guidance of Drs. Maureen Holasek and Hal Jacobson, ICCI is reaffirming its commitment to provide the most advanced treatment options for their patients. “This new technology offers the ability to visualize the breast in a way not possible via more conventional CT technologies. This provides us very high contrast images from which we can make our clinical choices” indicated Dr. Maureen Holasek.
ICCI is one of a network of three affiliated Cancer Centers in Central Florida. Their oldest location was founded in 1985 as Lake County’s first Cancer Center. ICCI opened in 2006 and is located on the campus of South Lake Hospital in Clermont, Florida.
Each year, more than 200,000 women are diagnosed with breast cancer in the United States. Early detection and treatment are the keys to survival, preventing cancer recurrence, and minimizing the volume of the breast being treated. Breast cancer is being detected in the early stages more often than ever before. This offers women the option to pursue breast-conserving therapy (BCT), or lumpectomy, in place of mastectomy. Approximately 150,000 women could qualify for BCT this year.
Most women will have some form of radiation following BCT. The most common form of radiation for breast cancer is Whole Breast Irradiation (WBI) typically administered on a large radiation delivery system called a LINAC or linear accelarator. WBI consists of two phases: the whole breast phase and the boost phase. The boost is a high dose of radiation to the lumpectomy cavity, where the cancer is most likely to return.
The most typical boost delivered from a LINAC uses high energy electrons delivered directly to the breast in a manner called “en face”, essentially meaning that they are directed straight on to the breast/chest. The dose delivered in this fashion has limited accuracy and is dependent upon several variables, such as the size of the breast, the size of the scar from the lumpectomy, the post-operative cavity, and the patient’s positioning and breathing motion. This typically leads physicians to assess a very large treatment area within the breast so that they have confidence that all the vulnerable tissue is treated. At the same time, heart, lung, and healthy breast tissue were also being exposed because of the en-face nature of the treatment delivery.
Another drawback of targeting a large area of the breast with the external electron boost, and doing so repeatedly to the same spot from the same direction over a number of days, is the degree of skin reaction. Symptoms can include a burning sensation on the skin and can result in fibrosis in/near the volume of tissue being treated.
“With normal electron boost, skin in one area gets a repetitive dose over many days, potentially causing the skin to break down, and can take a long time to heal,” says Piran Sioshansi, President and CEO of AccuBoost.
According to Sioshansi, a large multi-center study has shown the contribution of the boost dose for control of local recurrence, but the same study showed that the boost dose also increases the amount of fibrosis. This was particularly so in younger women.
With AccuBoost, the dose is broken up into four fields so each area of skin sees less dose than with electron boost. The radiation better focuses on the actual lumpectomy site and treats less volume of breast, decreases fibrosis, and so far patients say that skin reactions considered normal with electron treatments are not occurring.
“AccuBoost allows you to see what you treat and treat what you see,” says Dr. Maureen Holasek, Medical Director at ICCI. “When we use our image guidance and immobilization platform, we can make corrections based on the location of the lumpectomy site and integrate knowledge from the pathology report from the surgeon, without the worry of patient movement or respiratory motion,” continued Dr. Holasek.
With AccuBoost, the patient can be positioned exactly where she needs to be using the image-guided system, and the physician can visualize the size of the cavity and the exact location of the tumor bed.
“This is a unique technology as it provides us the ability to shape the radiation field while at the same time strongly limiting the radiation to any tissue other than what I am selecting to target within the breast” says Dr. Hal Jacobson. “The concept is extremely novel and ultimately strives to minimize damage to normal tissue while treating the exact location of the surgical cavity.” “Most recently, several presentations made at technical trade conferences showing the reduction in skin toxicity and in fibrosis” he added.
“Precision is the key factor,” says Dr. Holasek. “With more accuracy, we don’t expose any more healthy tissue than is necessary.”