Handheld device can spot skin cancers without requiring biopsy

A compact device that incorporates high-resolution millimetre-wave imaging (HR-MMWI) can diagnose malignant skin lesions as accurately as clinical examination and other detection techniques, potentially cutting the number of unnecessary biopsies in half, as reported in a study.

“We showed that real-time HR-MMWI could distinguish skin cancer and precancer lesions from benign tissues with an area under the receiver operating characteristic curve (AUC) of 0.996, and sensitivity and specificity of 97 percent and 98 percent, respectively,” according to researchers led by Negar Tavassolian, director of the Bio-Electromagnetics Laboratory at Stevens Institute of Technology in Hoboken, New Jersey, US.

The device was evaluated in 93 benign skin tissues (eg, melanocytic nevi, angiokeratoma, dermatofibroma, solar lentigo, and seborrheic keratosis), five melanomas, eight squamous cell carcinomas (SCCs), 10 basal cell carcinomas (BCCs), and 20 actinic keratoses (AK) from 71 patients (median age 61 years, 53.5 percent female). [Sci Rep 2022;doi:10.1038/s41598-022-09047-6]

With the a priori malignancy cutoff set at >0.5, the percentage of correct classifications in malignant lesions was found to be 95 percent in AK, 100 percent in melanoma, 100 percent in BCC, and 88 percent in SCC. In benign lesions, the corresponding percentage of correct classifications was 95 percent in nevi, 100 percent in angioma/angiokeratoma, 96 percent in seborrheic keratosis, 100 percent in dermatofibroma, and 92 percent in solar lentigo.

Millimetre-wave imaging

MMWI is the same technology used in concealed threat detection, security and surveillance, and nondestructive testing. The technology has previously demonstrated its capability in identifying biochemical and molecular changes in the skin that occur in the two most common types of skin cancer—BCC and SCC. [Proc IEEE 2007;95:1683-1690; IEEE Trans Instrum Meas 2006;55:1620-1627; IEEE Trans Med Imaging 2019;38:2188-2197; IEEE Trans Biomed Eng 2017;65:1320-1329]

In the current study, the team created a compact MMWI device, which operated with an ultra-wide bandwidth of approximately 100 GHz. To suppress noise and interference, the researchers devised an algorithm to fuse signals captured by multiple antennas, yielding high-resolution images of even a miniscule mole or blemish.

“Overall, the results of this work support the use of HR-MMWI in assisting skin cancer detection at the clinical interest level (ie, cancer/precancer versus benign)… [The device] is an affordable technique and requires less extensive training and user expertise,” Tavassolian said, adding that the classification of a given lesion can be performed in approximately less than 20 seconds.

Considering the device’s specificity rates for differentiating between benign and cancer tissues in this study, Tavassolian and colleagues believe that the device will help lower the number of unnecessary biopsies by >50 percent, saving time and effort for dermatologists.

“It will also reduce patient discomfort and provide significant cost reductions for both the individual patient and the nation’s healthcare system,” they added.

Next step in the research

Multiple noninvasive imaging techniques (ie, reflectance confocal microscopy, optical coherence tomography, multispectral digital skin lesion analysis, and electrical impedance spectroscopy) have been developed for diagnosing skin cancers and differentiating them from benign lesions. Their clinical utility, according to Tavassolian, is however limited as each provides information only under certain conditions.

Meanwhile, other advanced imaging technologies that can detect skin cancers are big and expensive, which bar their access in the clinic, she added.

“We’re creating a low-cost device that’s as small and as easy to use as a cellphone, so we can bring advanced diagnostics within reach for everyone,” Tavassolian said.

Tavassolian and colleagues noted that the algorithm that powers their device can be further improved to allow mapping of lesion margins, which will enable more precise and less invasive biopsying for malignant lesions.

Already, the researchers are looking into commercializing their technology and producing functional handheld millimetre-wave diagnostic devices to for as little as USD 100 each—a cost that is significantly lower than that of existing hospital-grade diagnostic equipment.

“The path forward is clear, and we know what we need to do,” said Tavassolian. “After this proof of concept, we need to miniaturize our technology, bring the price down, and bring it to the market.”