Confocal microscopy to noninvasively detect skin cancer

An emerging technology to avoid unnecessary skin biopsy

Skin cancer is the most common type of cancer worldwide. There has been a 500% increase in Europe in the past 25 years. In the US, more than two million people are diagnosed each year.
This means more cases than breast, prostate, lung, and colon cancer combined. The lifetime risk of developing skin cancer is estimated to be 20%.
Nonmelanoma skin cancer is rarely fatal and associated with a very low mortality rate. On the other hand, melanoma can be highly fatal. Around 100.000 people are diagnosed in the US in the year 2016. Skin cancer can be easily cured with early detection and excision.

The importance of early detection

And how the new technology helps

The most important part is early detection, especially for melanoma, which has a grim prognosis once it has metastasized. Until today, detection requires a biopsy to definitively determine if a lesion is malignant or benign.

Reflectance confocal microscopy may contribute to the diagnosis of melanoma as an add-on test in the diagnostic pathway to reduce over-diagnosis following dermoscopy. Reduction in the excision rate of benign lesions that look suspicious on clinical examination may be important particularly where treatment by removal is potentially difficult or harmful.
Confocal microscopy is the first imaging modality to offer single-cell resolution of the skin in vivo. Confocal microscopy uses a focused laser beam to illuminate a specific point within the skin and measures the reflection of light from that point. Multiple points are scanned across an area parallel to the skin surface to construct a grayscale image. Various depths can also be imaged to form optical sections. This method allows to project images of the epidermis, papillary dermis, and upper reticular dermis to be seen at resolutions comparable to histology.
A skin biopsy or excised tissue sample will remain the standard for skin cancer diagnosis. Although not a replacement for biopsy, confocal microscopy can provide an additional layer of information to avoid an unnecessary biopsy. This may benefit patients with a lesion of questionable concern in an anatomically aesthetic site such as the face. Additionally, patients may be spared from undergoing a presurgical biopsy and opt to go straight to surgical excision. Confocal microscopy has already been implemented in a handful of dermatology practices and academic medical centers in the United States.

The ultimate goal of the method is a non-invasive, non bloody diagnostic.