Breastlink Women’s Imaging Temecula recently participated in a clinical trial that tested a cancer screening machine designed to differentiate between benign and malignant breast tumors. The goal of the trial was to see whether the machine could reduce false positive diagnoses. It was conducted at 16 academic and private institutions across the nation. Dr. Tchaiko Parris, Director of Breast Imaging at Breastlink Temecula, oversaw the majority of the testing in Southern California. Results of the trial were published in Radiology, a leading medical journal, and will likely have a major impact on the future of cancer screening and diagnosis.
Breastlink Clinical Trials
Breastlink is heavily involved in medical research, to the benefit of our patients. Every year, we partner with labs and medical companies to conduct clinical trials at our sites, testing new drugs and machines against the current standard of care. Trials are open to all patients who meet the studies’ criteria, giving them access to cutting-edge medical treatments and a chance to improve breast cancer treatment for the patients who will come after them.
The trial, which was conducted by Dr. Parris, was focused on optoacoustic imaging – a cutting edge technique that fuses laser optical imaging and ultrasound. Ultrasound is already a commonly used supplemental screening tool. It creates grayscale images of internal organs with high frequency sound waves. Laser optical imaging examines internal organs using short, intense pulses of light. The pulses are emitted from a handheld probe pressed against the skin. Because different forms of light (visible, ultraviolet, and infrared) interact differently with different types of human tissue, tracking how the light pulses are absorbed and scattered provides insight into the tissue’s molecular properties.
In breast screening, laser optical imaging allows doctors to measure oxygen levels in the blood flow around a tumor. A malignant tumor absorbs oxygen at a significantly higher rate than a benign one, so if doctors detect high levels of oxygen in the surrounding bloodstream, it indicates the tumor is benign.
The SENO Trial
The trial was funded by SENO, the Texas-based health company that designed the new machine. Patients were invited to take part if they were over 18, had no prior history of breast cancer, had a confirmed breast mass less than four centimeters, and were categorized as BI-RADS 3, 4, or 5.
BI-RADS is short for Breast Imaging-Reporting and Data System. It allows doctors to estimate the likelihood a breast tumor will turn out to be cancerous. There are six BI-RADS categories.
- BI-RADS 1: Negative. No suspicious findings for cancer.
- BI-RADS 2: Benign. Patient has an identifiable mass, but it is not malignant.
- BI-RADS 3: Probably Benign. Chance of malignancy is 0-2 percent.
- BI-RADS 4: Suspicious.
- BI-RADS 4A: Chance of malignancy is 2-10 percent.
- BI-RADS 4B: Chance of malignancy is 10-50 percent.
- BI-RADS 4C: Chance of malignancy is 50-95 percent.
- BI-RADS 5: Highly Suggestive. Chance of malignancy is over 95 percent.
- BI-RADS 6: Known Biopsy. Malignancy has been proven.
Dr. Parris placed patients into a BI-RADS category based on the findings from a mammogram and an ultrasound, which was administered as part of the trial. Once they’d been categorized, the patients were given an additional exam using the optoacoustic machine. To preserve the integrity of the test, the results of these exams were not shared with Dr. Parris. Instead, they were sent to a separate team of radiologists who categorized the patients based solely on the optoacoustic data. The volunteers’ pathology reports and specimens were also sent to the optoacoustic team who cross checked them to ensure accuracy.
At the end of the trial, the team found that optoacoustic imaging increased diagnostic specificity from 28 percent to 43 percent compared to traditional ultrasound.In medicine, diagnostic specificity refers to the likelihood that a patient who tests negative does not have the disease. Sensitivity – the likelihood that a patient who tests positive has the disease – remained the same, with only a two percent difference between optoacoustic imaging and traditional ultrasound.
Optoacoustic imaging also allowed doctors to categorize the patients’ breast masses more accurately.Of the breast masses initially categorized as benign, 34.5 percent were downgraded and 6 percent were upgraded, while 16.5 percent malignant masses were downgraded and 30.6 percent were upgraded.
Optoacoustic imaging also seemed to help eliminate ambiguity when it came to evaluating a patient’s BI-RADS. This is significant because the BI-RADS level affects whether a patient will be given a biopsy or whether her tumor will be monitored. And while doctors are trained to be cautious, often recommending women for biopsies if the findings from the mammogram and ultrasound are ambiguous, optoacoustic imaging may help patients avoid biopsies when they are not needed. In addition, it may also help to positively identify small cancers, rather than waiting for them to grow or develop an integral change or a change in the margins.
Implications for Breast Cancer Screening
Though the results from the SENO trial are encouraging, Dr. Parris warns it will probably be several years before optoacoustic imaging becomes a standard screening tool. More trials will be required before the machine proves its effectiveness. The machine’s design also requires tinkering. It was extremely sensitive andrequired a high level of maintenance while it was at Breastlink. Finally, because ultrasound is operator dependent, technologists will need to be retrained before the machine can be used to make reliable assessments.
Despite this, Dr. Parris is optimistic. She believes future trials will build upon the positive results of the SENO trial and demonstrate the value of optoacoustic imaging, leading to better outcomes for patients.