Detecting skin cancer when the human eye can’t

Dr. Clara Curiel and Lynne Morrison use the SciBase.
Dr. Clara Curiel and Lynne Morrison use the SciBase.

Early detection is key to curing skin cancer, but melanoma and non-cancerous moles can look very similar. Some melanomas can even mimic a mole with minimal atypical features, and distinguishing them in a clinical exam can be difficult and sometimes impossible. Currently, there is no way to confirm that a pigmented skin lesion is cancerous without first removing it, so some patients may undergo a biopsy only to discover nothing was wrong.

Now imagine an automated diagnostic device that can determine whether a suspicious mole is dangerous without doing a biopsy. Swedish company SciBase has created a device that aims to do just that. The method, which uses the electrical properties of healthy and cancerous skin to detect malignant melanomas, is being tested in clinical trials at 20 European centers and five American centers, including the Arizona Cancer Center.

“It’s a handheld device and you put it on a lesion and it tells you, suspicious or not suspicious,” said Clara Curiel, MD, director of the Arizona Cancer Center’s Pigmented Lesion Clinic, co-director of the Cutaneous Oncology Program and a principal investigator of the study.

Since May 2010, the Cancer Center – the top recruiter in the U.S. – has tested 155 lesions on 143 subjects using the SciBase method. So far, patients have been very willing to participate, said Senior Research Nurse Lynne Morrison, RN.

“Not one person has turned me down,” she said. “The patients are thrilled to help advance science.”

After a subject’s pigmented skin lesion is photographed with a digital camera and a magnifying dermatoscope attachment, the SciBase probe is pressed on normal skin near the pigmented skin lesion to give a reference reading and then on the lesion in question. A small disposable electrode on the tip of the probe applies a light current between two microscopic spikes, which are long enough to penetrate only the outermost layer of skin, not the layer that contains nerves. The results of the painless process appear on a screen as a graph demonstrating the resistance of the tissue and the outcome of the lesion measurement.

“It works with the assumption that electrical impedance spectroscopy at clinically relevant frequencies reflects cellular properties of the tissue that are different between normal and malignant cells,” Dr. Curiel said. “Therefore, the resistance of the atypical cells as the electricity passes through is different than in a normal cell. Based on that assumption, you can measure differences in skin lesions and identify the patterns that are more typical in malignant cells.”

The lesion is then removed and sent for histological analysis and the patient receives the follow-up care he or she requires. SciBase collects the digital images and pathology slides to compare the device’s results to the diagnosis.

While physicians don’t know the outcomes in this blinded study, previous published studies on the method have been promising. Earlier trials showed that the SciBase method is able to separate benign and malignant moles with a sensitivity exceeding 98 percent and specificity more than 20 percent better than dermatologists in the studies. It also distinguishes non-melanoma skin cancer from benign skin lesions with close to 100 percent sensitivity and 87 percent specificity.

If the device is validated and approved for use in the U.S., Dr. Curiel said it has the potential to improve early detection of melanoma, which is crucial to saving lives. Though it’s almost 100 percent curable when treated early, the incidence and mortality rates of melanoma have been increasing worldwide. The National Cancer Institute estimates that there were 68,130 cases of melanoma and 8,700 deaths from it nationwide last year.

“Someone dies of melanoma every hour in the U.S.,” Dr. Curiel said. “Early detection is key.”

Dr. Curiel, who holds the Alan and Janice Levin Family Endowed Chair for Excellence in Cancer Research, said the SciBase device could be particularly
helpful to primary care physicians and other health care professionals who might need further reassurance when diagnosing pigmented lesions.

“The ultimate added value of automated diagnostic devices in the clinical field will only be determined when devices like SciBase enter the market and are evaluated in the long term,” she said. “The adoption and impact of this approach will vary between dermatologists with different levels of expertise in assessing pigmented skin lesions and other healthcare providers such as general practitioners.”

The device might also play a role in increasing public awareness of skin cancer. Much the way some dermatologists now advertise having a particular cosmetic laser, physicians may someday advertise that they have a device to detect changes in concerning skin lesions, and that will hopefully encourage patients to be evaluated, Dr. Curiel said.

“Patients and the population in general are gravitating toward technology,” she said. “If they believe there is technology to do certain things, they might trust it more. I think it will drive a number of patients to go and get tested.”