Skin Cancer

Skin cancer is not only highly prevalent, it is preventable, treatable, and curable if caught early.

Section One of this FP Essentials monograph provides information about skin cancer epidemiology, the emerging use of technology for assessing skin lesions, and strategies for skin cancer prevention through protection from UV radiation exposure. The authors include a useful table showing the range of active ingredients in sunscreens and their advantages and disadvantages. I was interested to learn that many individuals apply much less sunscreen than is recommended.

Section Two focuses on skin cancer diagnosis. Although visual inspection is important, adding dermoscopy improves diagnostic accuracy for basal cell carcinoma and melanoma. Biopsy is, of course, required for a definitive diagnosis. The authors provide guidance on biopsy strategies and recommended margins. For nonmelanoma skin cancers, a variety of biopsy techniques can be appropriate. For melanoma, an excisional biopsy that removes the entire lesion and its base with margins of 1 to 3 mm is recommended so that the Breslow depth can be accurately measured and the stage of the melanoma determined.

Section Three covers management of actinic keratoses and keratinocyte carcinomas. Cryosurgery is effective for isolated actinic keratoses, but field-directed therapies, such as topical fluorouracil, are preferred for areas with multiple lesions. The authors review the recommended treatments for basal cell and cutaneous squamous cell carcinomas, for which management decisions are based on the location of the lesion and whether it has low-risk or high-risk features. It was helpful to be reminded that cutaneous squamous cell carcinoma can extend along terminal hair follicles, which can impact the usefulness of electrodesiccation and curettage.

Section Four addresses melanoma, which is mainly caused by somatic mutations that melanocytes acquire due to UV radiation exposure. It is the deadliest skin cancer because of its ability to metastasize. Determining the stage of the melanoma is essential, as the stage determines the treatment plan and the prognosis. Although cutaneous melanoma most often occurs in people with fair skin (Fitzpatrick skin types I and II), the highest percentage of late-stage melanoma occurs in people with darker skin (Fitzpatrick skin types V and VI).

We hope you find this edition of FP Essentials to be practical and helpful. When you have finished studying it and are ready to submit your answers to the quiz questions, please use the comment section to tell us what was most useful and what we can improve. In addition, we look forward to hearing your ideas for topics you would like us to cover in future editions.

Karl T. Rew, MD, Associate Medical Editor
Clinical Professor, Departments of Family Medicine and Urology
University of Michigan Medical School, Ann Arbor

Michelle Nelson, MD, FAAFP, is a board-certified family medicine physician and clinical assistant professor at Michigan State University College of Human Medicine, East Lansing. She has interests in dermatology and medical writing. She incorporates dermoscopy into her outpatient clinical practice. She completed the Jay Siwek Medical Editing Fellowship with American Family Physician and has several publications in that journal.

Remi K. Hamel, MD, is a board-certified dermatologist and Mohs surgeon at MyMichigan Health in Midland, Michigan, and a clinical assistant professor of dermatology at Central Michigan University, Mount Pleasant. He received his medical degree from Wayne State University School of Medicine in Detroit, Michigan. He completed a dermatology residency at Washington University in St. Louis, Missouri, and a fellowship in Mohs micrographic surgery and dermatologic oncology at Houston Methodist Hospital in Houston, Texas.

Jennifer Nash, MD, is a board-certified dermatologist in private practice with a special clinical interest in the detection and treatment of skin cancer. She completed her medical degree and dermatology residency at the University of Michigan, Ann Arbor, and founded Nash Dermatology in Midland, Michigan. She is a preceptor for medical students and residents, and a clinical lecturer on skin cancer management. She was previously a clinical assistant professor in the Department of Medicine at Michigan State University College of Human Medicine, East Lansing.

Disclosure: It is the policy of the AAFP that all individuals in a position to control CME content disclose any relationships with ineligible companies upon nomination/invitation of participation. Disclosure documents are reviewed for potential relevant financial relationships. If relevant financial relationships are identified, mitigation strategies are agreed to prior to confirmation of participation. Only those participants who had no relevant financial relationships or who agreed to an identified mitigation process prior to their participation were involved in this CME activity. Associate medical editor Michelle Nelson, MD, disclosed stock ownership in Eli Lilly. This relevant financial relationship was mitigated when she sold her shares in May 2024, before her work as FPE associate medical editor began. All other individuals in a position to control content for this activity have indicated they have no relevant financial relationships to disclose.

• Explain the potential impacts of skin pigmentation and response to sun (Fitzpatrick classification skin types I-VI) on skin cancer risks, presentations, and outcomes.
• Instruct patients on how to select and properly use sunscreen.
• Understand how dermoscopy improves diagnostic accuracy for skin lesions, particularly basal cell carcinoma and melanoma.
• Prescribe field-directed therapies such as topical fluorouracil to manage multiple actinic keratoses and areas of skin with field cancerization.
• Recognize the lesion and patient characteristics that stratify basal cell carcinoma and cutaneous squamous cell carcinoma into low-risk and high-risk categories.
• Select an appropriate biopsy technique for suspected nonmelanoma skin cancers based on lesion characteristics and patient factors.
• Biopsy skin lesions suspicious for melanoma using a technique that removes the entire lesion and its entire base, with margins of 1 to 3 mm.
• Ensure that follow-up skin examinations are completed at recommended intervals for patients with a history of skin cancer.