Skin Cancers
Basal cell carcinoma High-yield Verified · Sep 2026Skin cancers are malignancies of the epidermis: keratinocyte carcinomas — basal cell and squamous cell carcinoma — which are common and usually curable, and melanoma, a cancer of melanocytes that is less common but causes most skin-cancer deaths.
How UV rays damage skin DNA, what BCC, SCC and melanoma look like, the ABCDEs and the “ugly duckling”, why a suspected melanoma is excised and never shaved, what the USPSTF does and does not recommend, and the sun-protection teaching that is actually sourced — SPF 15 or higher, reapplied at least every 2 hours, shade from 10 a.m. to 4 p.m., and no tanning.
What’s going wrong in the body
The normal physiology, where it fails, and why the body’s compensation backfires.
01 Ultraviolet light damages skin-cell DNA
"UV radiation is a major etiologic factor for most nonmelanoma skin cancers, including squamous cell carcinoma and basal cell carcinoma, as well as melanoma." The CDC puts it simply: "Most skin cancers are caused by too much exposure to ultraviolet (UV) rays. UV rays come from the sun and tanning beds. UV rays can damage skin cells." Exposure to UV light "is the most significant modifiable risk factor for developing both nonmelanoma skin cancer and melanoma."
Two wavelengths, two kinds of damage. "UV-A, with its longer wavelength, penetrates the dermis and generates free radicals." "UV-B, with a shorter wavelength, penetrates to the level of the stratum basale of the epidermis, leading to the formation of pyrimidine dimers, such as thymidine dimers." UV also weakens the skin’s defenses: it "causes dose-dependent suppression of the cutaneous immune system, impairing immune surveillance against emerging skin cancer." A tan is not protection — "Any change in skin color after UV exposure (whether it is a tan or a burn) is a sign of injury, not health."
The damage hits different genes in different cells. "Most cutaneous squamous cell carcinomas (90%) exhibit UV-induced p53 gene mutations," and p53 mutation is also the commonest abnormality in the precursor, actinic keratosis — "rough, gritty skin papules on an erythematous base." In BCC, "Inactivating mutations in the PTCH1 gene are present in approximately 70% to 90%," with "a latency period of 15 to 20 years between UV damage and the clinical onset of BCC." Melanoma arises from melanocytes; "nearly 40% to 50% of cutaneous melanomas have mutations in BRAF," which "activates the mitogen-activated protein (MAP) kinase pathway," and "Melanoma has a relatively high risk of systemic spread."
02 Three cancers, three behaviours — look, growth and spread
Basal cell carcinoma — common, slow, local. "BCC is the most common malignancy in humans." It "typically presents as a shiny, pink- or flesh-colored papule or nodule with surface telangiectasia," often on the face; patients "frequently report a history of crusting and recurrent bleeding." "BCC is typically a slow-growing tumor with very low metastatic potential" — metastasis "is exceedingly rare" — but "delayed or inadequate treatment can result in significant local tissue destruction."
Squamous cell carcinoma — scaly, can spread. The CDC: SCC "usually appears as a firm, red or skin-colored bump, a scaly patch, or an open sore that bleeds." Its overall mortality is about 1% to 2%, "with approximately 3% of cases metastasizing," and "The lymph nodes are the most common site of metastasis." Transplant recipients on immunosuppression "have a 65- to 250-fold increased risk of developing squamous cell carcinoma."
Melanoma — rarer, deadlier. "Invasive melanoma represents about 1% of skin cancers but results in the most deaths," and "it is the most common cancer in young adults aged 25 to 29 years." Most arise from normal skin: "more than 50% of the cases arise in apparently normal areas of the skin. Melanoma can occur anywhere, including on mucosal surfaces and the uvea," and acral lentiginous melanoma is "usually found in nailbeds." Prognosis follows thickness and ulceration, the core of AJCC staging.
03 Finding it and treating it — and what screening evidence actually says
Recognize change. "A change in your skin is the most common sign of skin cancer. This could be a new growth, a sore that doesn’t heal, or a change in a mole." For melanoma the CDC teaches the ABCDEs — Asymmetry, Border ("The border is jagged"), Color ("The color is uneven"), Diameter ("The mole or spot is larger than a pea"; NCI and StatPearls use greater than 6 mm), and Evolving ("The mole or spot has changed over the past few weeks or months") — and "Any new or changing lesion that differs from other body nevi" is suspicious.
Biopsy the right way. For keratinocyte cancers, "A shave or punch biopsy is typically sufficient," but for melanoma "complete excisional removal is recommended." NCI: "Suspicious lesions should never be shaved off or cauterized," because "the tumor staging of melanoma is based on the depth of invasion." Treatment: BCC and SCC are usually removed surgically — "Mohs surgery provides the best long-term cure rate of all treatment modalities for BCC" — while melanoma gets wide local excision, sentinel node biopsy "in melanomas with T1b or higher staging," and, for higher stages, immunotherapy or targeted therapy.
Screening evidence is limited. The USPSTF concludes "the current evidence is insufficient to assess the balance of benefits and harms of visual skin examination by a clinician to screen for skin cancer in adolescents and adults" — an I statement that "does not apply to persons with a personal or family history of skin cancer" or to people with symptoms. What the USPSTF does recommend is counseling fair-skinned people aged 6 months to 24 years about minimizing UV exposure.
Causes & risk factors
Modifiable factors are teaching targets — the patient can act on them.
Signs & symptoms
Each finding tied to the mechanism that produces it — and the triage it calls for.
Diagnostics
Complications
Medications for this condition
Why each class is prescribed here — every card links to its full pharmacology page.
Melanoma systemic therapy. Stage III adjuvant options "include nivolumab, pembrolizumab, or dabrafenib/trametinib if BRAF mutated"; advanced melanoma: checkpoint inhibitors (anti-PD-1, anti-CTLA-4, dual), BRAF inhibitors "for patients who test positive for the BRAF V600 pathogenic variant," MEK inhibitors, TIL therapy and T-VEC. Advanced BCC: vismodegib (hedgehog inhibitor) — taste disturbance, muscle cramps, alopecia, and rarely "teratogenicity." Topical 5-fluorouracil and imiquimod for actinic keratoses and superficial lesions — topical 5-FU on sun-damaged skin "prevents additional actinic keratoses and SCC requiring surgery," with local "erythema, irritation, and crusting."
Treatment of immune-related adverse events — for pembrolizumab and nivolumab, NCI notes the FDA label recommends "withholding the drug and administering corticosteroids" for suspected irAEs.
A risk factor, not a treatment. "Immunosuppression after organ transplant is associated with an increased risk of SCC and BCC"; transplant recipients need close skin surveillance.
Voriconazole is a listed SCC risk factor — note it in the history of a patient with new skin lesions.
Beyond medications
- Surgery for BCC and SCC — "the standard approach is surgical treatment using destructive methods such as electrodesiccation and curettage or surgical excision"; Mohs surgery is "the gold standard for managing high-risk BCCs and recurrent BCCs" because it examines "100% of surgical margins."
- Melanoma — wide local excision "up to the muscle fascia" with margins by thickness; sentinel node biopsy for T1b or higher; after a positive sentinel node, observation rather than completion dissection is the current preference.
- Actinic keratoses — cryotherapy, topical agents or photodynamic therapy.
- Radiation therapy for aggressive or recurrent BCC in poor surgical candidates.
- Sun protection (CDC, FDA via USPSTF) — shade; clothing covering arms and legs; a wide-brimmed hat; wraparound UV-blocking sunglasses; broad-spectrum sunscreen SPF 15 or higher, "reapplied at least every 2 hours"; UV is strongest 10 a.m. to 4 p.m. (daylight saving time); protection "all year, not just during the summer"; no tanning beds.
- Sunscreen — keep the evidence honest. NCI: sunscreen prevents sunburns and actinic keratoses, but RCTs showed "no benefit in preventing melanoma," and sunscreen "may encourage more sun exposure." Sun avoidance also has harms, including "impaired vitamin D metabolism."
Nursing considerations
The RN-specific layer — each action paired with the reason it matters.
How a real nurse thinks
The clinical-judgment loop, worked for a typical presentation — reasoning, not reference.
- 1 Recognize cues
Three kinds of lesion: a bleeding scaly plaque on sun-exposed scalp (SCC pattern), a changing mole that is asymmetric, has a jagged border, uneven color, is larger than 6 mm and is evolving and itching (melanoma ABCDEs), and rough gritty papules (actinic keratoses). Risk factors: long-term immunosuppression after transplant, heavy outdoor UV, sunburns and tanning-bed use.
- 2 Analyze cues
The mole meets every ABCDE feature — melanoma must be ruled out, and "clinicians should always consider melanoma a potentially deadly diagnosis to miss." The scalp lesion fits SCC, a cancer transplant recipients develop at a 65- to 250-fold increased rate. The papules are actinic keratoses, the precursor of SCC.
- 3 Prioritize
The suspicious mole comes first — it needs prompt dermatology referral for excisional biopsy. The scalp lesion also needs biopsy; the actinic keratoses and sun-protection teaching follow.
- 4 Generate solutions
Report both lesions to the provider and arrange dermatology referral; explain that a suspected melanoma is removed whole, not shaved. Plan teaching on sun protection, tanning beds and skin self-awareness, and ask the team about ongoing skin surveillance for a transplant recipient.
- 5 Take action
The nurse documents and measures both lesions, reports them to the nephrologist, and arranges a prompt dermatology referral. The nurse teaches: shade and clothing, a wide-brimmed hat, broad-spectrum SPF 15 or higher reapplied at least every 2 hours, avoiding 10 a.m. to 4 p.m. sun, no tanning beds — "A suntan does not indicate good health" — and reporting any new or changing spot.
- 6 Evaluate
Excisional biopsy confirms a melanoma and punch biopsy an SCC. He is scheduled for wide local excision with sentinel node evaluation, and for SCC excision. He can explain why a tan is skin damage and agrees to regular skin checks with dermatology.
Scenario — you’re the nurse
Work each question before revealing the answer. Rationales explain the wrong options too.
A 58-year-old man, 6 years after a kidney transplant, takes tacrolimus and mycophenolate. He worked outdoors for decades. He mentions a sore on his scalp that keeps bleeding, and his wife is worried about a mole on his back.
Q1 Select all that apply Which features of the back lesion suggest melanoma? Select all that apply. - A. Irregular, jagged border
- B. Several shades of brown and black
- C. Diameter 9 mm
- D. Recent growth and itching
- E. Located on the back
Reveal answer & rationale
Q2 Multiple choice The patient asks if the doctor can ‘just shave off’ the mole. What is the nurse’s best response? - A. ‘Yes, a shave biopsy is the standard for all skin lesions.’
- B. ‘A suspected melanoma is removed whole, because staging depends on how deep it goes.’
- C. ‘It can be burned off with cautery instead.’
- D. ‘It can wait until your next annual visit.’
Reveal answer & rationale
Q3 Multiple choice Why is this patient at especially high risk for squamous cell carcinoma? - A. He takes immunosuppressants after an organ transplant
- B. He has no palpable lymph nodes
- C. He is 58 years old
- D. The lesion is on his scalp
Reveal answer & rationale
Q4 Select all that apply Which sun-protection teaching is accurate? Select all that apply. - A. Use broad-spectrum sunscreen SPF 15 or higher and reapply at least every 2 hours
- B. UV rays are strongest from 10 a.m. to 4 p.m.
- C. A base tan from a tanning bed protects against burns
- D. Protect your skin all year, including on cloudy days
Reveal answer & rationale
Q5 Multiple choice A healthy adult with no personal or family history asks whether everyone needs an annual skin-cancer screening exam. What does the evidence say? - A. The USPSTF strongly recommends yearly exams for all adults
- B. The USPSTF found the evidence insufficient to assess benefits and harms of clinician skin screening in people without symptoms
- C. Screening is harmful and should never be done
- D. Only children need skin exams
Reveal answer & rationale
Common questions
What causes skin cancers?
Which medications are used to treat skin cancers?
What are the ABCDEs of melanoma?
What SPF sunscreen should people use?
Does basal cell carcinoma spread?
Why is a suspected melanoma excised rather than shaved?
Sources
- Skin Cancer — StatPearls — StatPearls (NCBI Bookshelf)
- Malignant Melanoma — StatPearls — StatPearls (NCBI Bookshelf)
- Basal Cell Carcinoma — StatPearls — StatPearls (NCBI Bookshelf)
- Cutaneous Squamous Cell Carcinoma — StatPearls — StatPearls (NCBI Bookshelf)
- Melanoma Treatment (PDQ®) — Health Professional Version — National Cancer Institute
- Skin Cancer Prevention (PDQ®) — Health Professional Version — National Cancer Institute
- Symptoms of Skin Cancer — CDC — Centers for Disease Control and Prevention
- Reducing Risk for Skin Cancer — CDC — Centers for Disease Control and Prevention
- Skin Cancer Prevention: Behavioral Counseling — Final Recommendation Statement (2018) — U.S. Preventive Services Task Force
- Skin Cancer: Screening — Final Recommendation Statement (2023) — U.S. Preventive Services Task Force
Reviewed by Hae Suk Lee, RN
Educational summary for nursing students. Scenarios are fictional teaching cases. Always verify against current guidelines and your institution's protocols before acting in practice. Not medical advice.