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New Technology To Help Early Skin Cancer Diagnosis

April 11, 2000

Computer scientists in the UK have invented a new technology to help doctors diagnose skin cancer while it is still in its early stages, greatly improving the chances of successful treatment.


The work has been carried out by a team led by Dr Ela Claridge in the University of Birmingham's School of Computer Science. The Engineering and Physical Sciences Research Council has just awarded the group a major grant to investigate ways of obtaining even more detailed information from the technique.

While the technique can be applied to many skin conditions, the researchers are concentrating on the diagnosis of malignant melanoma, a form of skin cancer. This occurs when melanocytes - cells which are found in the outer layer of skin, the epidermis - become cancerous and start multiplying out of control.

As the melanoma develops, the cells can descend into the next layer of skin, the dermis, which contains blood and lymph vessels. These can carry the malignant cells to other parts of the body, spreading the cancer.If the melanoma is detected while it is still in the epidermis it can safely be removed by surgery. The deeper it has descended the worse the prognosis for the patient.

The role of melanocytes is to produce a brown pigment, melanin, which protects the skin against ultraviolet light. Excessive growth of melanocytes manifests itself by a change in the pigment of the skin."Most GPs will not have seen many melanomas, so will often refer suspicious cases routinely to the dermatologist, where there are long waiting lists," says Dr Claridge. "Even consultants can have problems in deciding if a melanoma is malignant, and may carry out surgery just to be on the safe side."

The aim of the research has been to develop a way of helping doctors decide quickly and easily whether a change in a patient's skin pigmentation is harmless or potentially sinister.The technique the Birmingham researchers have invented centres on how the structures of human skin interact with light.

Within human skin there are many different components, including haemoglobin in blood, a protein called collagen and melanin itself. These various components absorb and reflect light differently and in a quite specific way - each has a different absorption 'fingerprint'. "We can develop a model of 'normal' skin and determine its response to light," says Dr Claridge.

White light is shone onto the skin and the reflected portion is picked up and analysed by computer. The different wavelengths of light that have been absorbed or reflected correlate with the relative proportion of the different components of skin present in each layer.

In this way a unique three-dimensional model of skin coloration can be constructed, enabling the system to compute colour changes occurring within the different layers of skin.If there is melanin in the dermis, for example, the pattern of the absorption of light in the three-dimensional 'colour space' will indicate this.

A prototype device, called a SIAscope - for 'spectrophotometric intracutaneous analysis'- has been developed by a Cambridge-based company, Astron Clinica, and is now being trialled by the team's clinical collaborators in Addenbroke's hospital, Cambridge. The data obtained from the clinical studies will be used further to refine the technique to enable it to deliver more detailed information to help doctors make a rapid and accurate diagnosis.

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Engineering and Physical Sciences Research Council (EPSRC)