Melanoma is a type of skin cancer that develops from pigment-producing cells known as melanocytes. In women, they most commonly occur on the legs, while in men they most commonly occur on the back. About a quarter of melanomas develop from moles – if they change by growing larger, having irregular edges, change in color, are itchy, or cause the breakdown of the skin, it could be a clear sign of the tumor. 

It is the most-deadly of the three primary skin cancers, the other two being basal cell and squamous cell carcinoma.

The main cause of melanoma is exposure to ultraviolet light (UV) light (from the sun or tanning machines) in those people who have low levels of protective skin pigment called melanin. Using sunscreen and avoiding UV light can prevent melanoma; patients are typically treated by surgery, but if the cancer has spread to the lymph nodes, more advanced treatment is needed. 

With treatment, the five-year survival rates in the US are 99% among those with localized disease, but just 65% when the disease has spread to lymph nodes and 25% among those whose melanoma has spread even farther.  

Now, for the first time, an optical technology developed at Tel Aviv University (TAU) will make possible an automatic and immediate melanoma diagnosis, thus saving the lives of many patients. This innovative technology, based on special optical fibers, can distinguish between a benign lesion on the skin and a malignant one, using a non-invasive, and painless process.

It was been developed in the laboratory of Prof. Abraham Katzir of TAU’s Sackler Faculty of Exact Sciences and was tried successfully on 100 patients in a major Israeli hospital. The findings were published in the journal Medical Physics under the title “Noninvasive mid‐IR fiber‐optic evanescent wave spectroscopy (FEWS) for early detection of skin cancers.” 

Katzir, who was born 80 years ago in Jerusalem, is the son of Prof. Aharon Katzir, also a scientist, who was murdered in 1972 in Ben-Gurion Airport attack by Japanese terrorists. His uncle, Prof. Ephraim Katzir, was the fourth President of the State of Israel. 

The eminent TAU professor explained that in the case of melanoma, immediate diagnosis can save lives. When a suspicious lesion is found on the skin during a routine examination, it is removed in a minor surgical procedure and sent to a laboratory for testing. A pathologist diagnoses the lesion and determines whether it is melanoma. In most cases where melanoma is discovered early, when it is still superficial and less than one-millimeter-thick and it is removed, the patient recovers. Late diagnosis, when the melanoma is more than one-millimeter-thick, significantly reduces the chances of recovery and is life threatening. 

“The idea that guided us in developing the technology was that in the visible range, there are various substances, having various colors that are not characteristic of each substance.  On the other hand, in the infrared region, various substances have different ‘colors’ of a sort, depending on the chemical makeup of each substance,” he continued.  “Therefore, we figured that with the help of devices that can identify these ‘colors,’ healthy skin and each of the benign and malignant lesions would have different ‘colors’ that would enable us to identify melanoma.”

Katzir got his doctoral degree from the Hebrew University in Jerusalem in 1974 and joined Caltech in Pasadena, California as a senior research fellow. He is an expert in the fields of biomedical optics and fiber optics. His group at Tel Aviv University developed special fibers made of crystalline silver halides that  are among the few that are highly transparent in the middle-infrared (mid-IR). 

He and members of the group have been involved with research and development of new methods and new systems based on these fibers. They made significant contributions to the use of mid-IR fibers for scientific, medical, industrial and environmental protection applications. In the course of this work, Katzir collaborated with leading scientists in major national laboratories, universities, research institutions and industrial companies all over the world.

The professor is chairman of ILEOS, the Israel Lasers and Electro Optics Society, and of the OASIS (Optical Applied Science in Israel) international conferences that this society organizes in Israel. 

His research group developed special optical fibers that are transparent in the infrared. The group, in collaboration with physicists Prof. Yosef Raichlin of Ariel University in Samaria, Dr. Max Platkov of the Negev Nuclear Research Center and Svetlana Bassov of Prof. Katzir’s group, developed a system, based on these fibers, that is suitable for the requirements of evaluating skin. The researchers connected one end of this type of fiber to a device that measures the ’colors’ in the infrared, and touched the other end lightly, for several seconds, to a lesion on a patient’s skin. The fiber made it possible to check immediately the ‘color’ of the lesion. 

With the help of the new system, physicists performed measurements of the ’color’ of each lesion, before it was removed and sent to a pathology laboratory. The researchers showed that all of the lesions that were determined by pathologists as being of a certain type, such as melanoma, had a characteristic ’color’ in the infrared. Each lesion of a different type had a different ’color.’ 

“This technology gives us a kind of ‘fingerprint’ that makes a clear diagnosis of the various lesions possible, by measuring their characteristic ’colors,” Katzir noted. “In this way, lesions can be diagnosed using a non-invasive optical method, and the physician and the patient receive the results automatically and immediately.  This is unlike the test that is routinely used, which involves surgery, and the pathological diagnosis takes a long time.”  Following the success of the study, the researchers plan to confirm the evaluation method on hundreds of patients more. 

“Melanoma is a life-threatening cancer, so it is very important to diagnose it early on, when it is still superficial,” he concluded. “The innovative system will enable every dermatologist to determine the character of a suspicious lesion automatically, and particularly if it is melanoma. This system has the potential to cause a dramatic change in the field of diagnosing and treating skin cancer, and perhaps other types of cancer as well. The challenge will be to make this technology, which is still expensive, something that will be used in every hospital or clinic.”