· Various treatments such as cryotherapy and targeted therapy
· Dermoscopy as a powerful diagnostic tool
· Active use of artificial intelligence technology for skin cancer diagnosis
Even amid social distancing due to COVID-19, the world is cooperating for better health care. Health Kyunghyang is the first media company to operate a multilingual edition, rapidly delivering domestic health and medical news overseas. This year, we went one step further and prepared a particular article called ‘Medical Discussion with World’s Great Scholars’. From the latest treatment for various diseases to the management of health care development in future medicine, we will communicate with distinguished researchers in the medical field to provide readers with a broader range of information. The seventh topic is ‘The latest trends in diagnosis and treatment of skin cancer.’ Please check out the numerous opinions of scholars from all over the world. <Editor’s Note>
In general, skin cancer tends not to be taken as seriously as other cancers. However, the number of skin cancer patients is rising worldwide due to increased UV exposure and aging. Fortunately, 90% of skin cancer is basal cell carcinoma that can be managed by surgery. So early diagnosis and treatment are so essential. As the diagnosis and treatment methods for skin cancer have diversified, it is expected to promote the quality of life through personalized treatment for each patient.
The participants of this discussion were ▲Professor Chang-Hun Huh, Department of Dermatology, Seoul National University Bundang Hospital (Vice President, Korean Society of Dermatological Surgery) ▲Myrto Georgia Trakatelli, Professor of Dermatology, Aristotle University of Thessaloniki, Greece (Director, International Society of Dermatological Surgery) ▲Li Hang Professor of Dermatology, Peking University, China (Executive Deputy Director, China Skin and Immunology Clinical Research Center) ▲ Shigeto Matsushita, Professor of Dermatology, Kagoshima University Hospital, Japan (Chairman, 6th Asian Congress of Dermatologic Surgery, 2021)
■Discussion Main Issues
Since skin cancer is painless and develops from usual spots or nodules to cancer, skin cancer is complicated to diagnose with the naked eye. It can be easily mistaken for a spot or age spot.
However, thanks to the development of multiple diagnostic tools and the latest treatment technology, it has become achievable to identify the margin of the tumor before surgery and an accurate diagnosis. A new trend in diagnosing and treating skin cancer that combines the expert's rich clinical experience, know-how, and advanced medical technology is emerging.
- What is the current trend of skin cancer patients in each country?
Korean Professor Chang-Hun Huh (hereafter, Huh): Based on the Health Insurance Review and Assessment Service statistics, the number of skin cancer patients in Korea increased from 19,236 in 2016 to 27,211 in 2020, an increase of more than 40% over the past five years. The increased outdoor activities such as leisure have influenced the rise of skin cancer related to UV rays. An expansion in the aging population with weak immunity and poor ability to remove abnormal cells could also be significant causes.
Greece Professor Myrto Georgia Tracatelli (hereafter, Tracatelli): Skin cancer is on the rise worldwide. In Europe, skin cancer has become an endemic disease (a disease that occurs due to the specific environment of the region). I believe that climate change, such as ozone layer change and increased UV exposure, played a part.
Chinese Professor Li Hang, (hereafter, Li): The number of skin cancer patients increases in China. China is aging rapidly. As the risk of developing skin cancer progress with aging, the number of patients is bound to increase in the future. Changes in people's lifestyles, such as an increase in outdoor activities, also have a consequence. In addition, as interest in skin health progress, more and more people are trying to accurately monitor symptoms at dermatologists that were overlooked in the past, so more patients are precisely diagnosed.
Japanese Professor Shigeto Matsushita (hereafter Matsushita): In Japan, the number of skin cancer patients increases due to an increase in UV exposure and an aging population, too. In addition, as media activities to promote skin cancer awareness have been actively conducted, the number of latent skin cancer patients visiting a dermatologist has grown.
- What is the primary consideration in skin cancer surgery?
Huh: Before surgery, I try to precisely examine the patient's overall health and the tumor margin so that cancer tissue can be resected entirely while minimizing damage to normal tissue. For this, the tumor margin is identified with a dermoscopy, a surgical polarizing loupe (magnifying glass). This equipment allows to observe 2-3 mm depth from the skin surface and help to excise exact only the cancerous tissue.
Trakatelli: Complete resection of cancer should be prioritized over reconstructive surgery for restoration. In particular, keratinocyte tumors tend to recur, so margin control for complete resection is critical. The currently widely used surgical method is the Mohs operation (a process of repeated excision based on the biopsy results). There are also various surgical methods modified here.
Li: We focus on promoting a customized treatment plan by understanding the patient's condition. We also endeavor to eliminate cancer and regenerate the skin healthy and clean. In addition, we aim to treat elderly patients or patients with severe deterioration as far as the treatment does not threaten life or reduce the quality of life. To this end, we thoroughly grasp what the patient wants and apply multiple techniques to magnify the surgical outcomes.
Matsushita: I think the most important point is the complete excision of cancerous tissue and the maintenance of the safety and function of the skin. Also, it requires a good cosmetic result.
- How do you treat complicated patients who are difficult to operate?
Huh: Older patients are often unable to withstand the surgical procedure. In addition, it is challenging for patients with severe underlying medical conditions to perform the surgery. In this case, I personally prefer to use a cryotherapy. Of course, photodynamic therapy can be used, but in these cases, patients have to wait for a long time after applying a photosensitizer, and it is quite painful.
But with cryotherapy, the discomfort only last for seconds and more convenient. In addition, an immunomodulatory treatment using “imiquimod” can be applied for those who has shallow skin cancer on the surface. But this drug can cause severe oozing, so explanation of this reaction to the patient before treatment is highly required. Recently, a target therapy agent has been marketed but it is still not easy to get in Korea, so it is not actively used in the field.
Trakatelli: Radiation therapy is considered for elderly patients who does not want to undergo skin cancer operation. In addition, recently developed target anticancer agents like “vismodegib” for basal cell carcinoma or “pembrolizumab” for squamous cell carcinoma, are used for skin cancers that have a high risk of recurrence or are challenging to treat. We always ponder about choosing the most appropriate treatment method according to the patient's tumor characteristics.
Li: Photodynamic therapy is mainly applied for superficial skin cancer that has not penetrated deep into the skin because it can be offered at an outpatient clinic. Its therapeutic effect has been proven through relatively many papers. Radiation therapy may be a treatment option in patients who cannot undergo surgery or who recur.
Matsushita: It depends on the type of skin cancer and approval status of each country. Typically, an immunomodulatory drug called “imiquimod” is effective for shallow skin cancer (superficial basal cell carcinoma, Bowen's disease, or squamous cell carcinoma in situ) with unclear tumor margin. This drug is also recommended for areas that are difficult to operate, with other co-morbidity, especially in the face and under the legs.
Although this drug is approved in Japan for the treatment of actinic keratosis, I prefer it as a non-surgical treatment. Radiation therapy is mainly performed for patients with advanced squamous cell carcinoma who are too aged or dangerous for surgery. In addition, Japanese dermatologic surgeon can use chemotherapy, immune checkpoint inhibitors or targeted therapies that had a lot of evidence recently are frequently used in advanced melanoma patients.
- Thanks to progressions in medical technology, a new wind is blowing in diagnosing and treating skin cancer. What are the latest trends in skin cancer diagnosis?
Huh: In Korea, dermoscopy was approved as a new medical technique in 2017 and is receiving a lot of attention. Dermoscopy can magnifies the detailed structure of the skin and help an efficient and precise diagnoses of skin cancer without a biopsy. Personally, I wrote the first Korean textbook, “Dermoscopy for Asian” to help the use of dermoscopy in daily practice.
Recently, I also participated in developing a non-invasive, real-time diagnosis of skin cancer using the technology named “LIPS (Laser-Induced Plasma Spectroscopy)” and artificial intelligence. According to the performance evaluation results of this device, skin cancer can be detected with a sensitivity of 95% and a specificity of 87%. With these kinds of diagnostic tools, we could reduce unnecessary biopsies and increase patient convenience.
Trakatelli: Now, dermoscopy became an essential diagnostic tool for dermatologists like a stethoscope. Recently, confocal microscopy, optical coherence tomography (OCT), and high-frequency ultrasound have been developed to examine the tumors in a living tissue without removing it. These new diagnostic technologies are being effectively combined with artificial intelligence. Skin cancer diagnosis by artificial intelligence has been advanced remarkably over the past few years and it is expected to replace dermatologists soon.
Li: Minimally invasive diagnostic tools with reduced scar and increased accuracy are being developed. In addition, many studies to speed up skin cancer diagnosis are being conducted, and a self-diagnosis kit for skin cancer is gradually increasing.
Matsushita: In many European countries, preoperative confocal microscopy or optical coherence tomography, or a combination of these two are recommended for the early detection of asymptomatic skin cancer and a surgical planning. But unfortunately, it is not approved officially in Japan. Instead, dermoscopy and ultrasound are widely used in Japan.
- We would like to know about the latest treatment trends for skin cancer.
Huh: Recently, a lot of research on radiation therapy, specially surface radiation therapy for nonmelanoma skin cancer has been conducted over the world. Due to safety issues such as shielding (blocking radiation to the outside), a conventional radiation therapy could not be made in an outpatient clinic. However, the device itself is getting smaller and lighter which can be operated in a small room with a shield. Accordingly, immediate treatments at a dermatologic clinic without referral to a radiology department are increasing. Also, a brand-new techniques using alpha rays emitted from radium 224 has been developed in Israel, and clinical trials will verify its effectiveness soon. I have participated in the development of X-ray skin cancer treatment equipment using carbon nanotubes with KAIST.
Trakatelli: We expect many targeted therapies and immunotherapeutic agents to be developed to treat inoperable or metastatic skin cancer. This can help patients as one of the systemic treatment modalities
Li: Since scars are a crucial aspect of skin cancer treatment, I think that minimally invasive surgery that minimizes scars will increase more and more. Customized treatments for each type of skin cancer and equipment to help speed up recovery will be continuously developed, too. Above all, to be more beneficial for patients, the government support must be provided to reduce the burden of treatment costs in line with these changes.
Matsushita: The key point in skin cancer surgery is establishing a skill to bring the best results with minimal burden. Therefore, Japanese dermatologic surgeon are currently conducting multicenter clinical trials on the results of basal cell carcinoma with a narrower border (JCOG2005) and nail melanoma treatment with the finger preservation without amputation (JCOG1602).
Skin cancers of Asians are different from those of Western people, such as melanoma occurring more frequently on the fingers and toes and pigmented basal cell carcinoma found more frequently. Therefore, Asian dermatologists should understand the characteristics of Asian skin cancer and actively cooperate to establish new treatment techniques and Asian guidelines for skin cancer treatment.
