Pocket ObGyn – Skin Cancer Screening
See Abbreviations
Basal Cell Carcinoma (J Natl Compr Canc Netw 2010;8:836; BMJ 2003;327:794)
- Definition: Arises from epidermal basalis, locally invasive
- Epidemiology: Most common skin Likely 1–3 million BCC/y in US. 30% lifetime risk if Caucasian.
- Risks: Age, race, UV light exposure esp intermittent & intense, chronic arsenic exposure, ionizing radiation, immunosuppression, & PUVA therapy for psoriasis
- Pathophysiology: Sun exposure/inflammation. Genetics – PTCH1, chromo 9, tumor suppressor gene, two-hit
- Clinical manifestations: 70% on face, 15% on trunk
Nodular: 60% of cases, flesh-colored papule, pearly or translucent, telangiectatic vessel, may have ulceration
Superficial: 30% of cases, mostly on trunk, scaly plaque, rimmed w/ translucent micropapules
Morpheaform: Smooth, flesh-colored plaques, atrophic, ill-defined borders, aggressive
Basal cell nevus syn: Autosomal dominant inheritance, PTCH1 mutation, p/w multi BCCs at a young age, macrocephaly, bifid ribs, bone cysts, palmar pitting, & medulloblastoma.
- Tx: Less aggressive BCC (<6 mm diameter on face/hands/feet, <10 mm on head/neck,
<20 mm all other areas; nodular or superficial histopathology, no perineural invasion; primary lesion, defined borders, immunocompetent, no prior radiation) ® electrodessication & curettage, surgical excision. More aggressive BCC ® Mohs Surg, surgical excision, XRT.
- Prog: Excellent, metastasis rate 55%, but 40% of pts ® 2nd BCC £5 y
Squamous Cell Carcinoma (NEJM 2001;344:975)
- Definition: Arises from epidermal keratinocytes, locally invasive
- Epidemiology: 2nd most common skin cancer, 4–9% lifetime risk for US women
- Risks: Same as BCC, see above
- Pathophysiology: UV light, esp >30000 cumulative hours, similar to p53 mutation & other tumor suppressor genes. Prevention: Protection from sun exposure, retinoids.
Actinic keratoses: Precursor lesion, scaly erythematous macules, 1% progress to SCC, 60% of SCC arise from actinic keratoses
- Clinical manifestations: 55% on head/neck, 35% on arms/legs
SCC in situ (Bowen dz): Well-defined borders, scaly plaque, erythematous Invasive SCC: Hyperkeratotic papules or nodules, firm, may have ulcerations Verrucous carcinoma: Well-defined, cauliflower-like growths
Xeroderma pigmentosum: Multigenic, autosomal recessive, sev sun sens, degeneration of skin & eyes
Epidermolysis bullosa: Blister formation w/ no prev trauma, increased risk of aggressive SCC
- Tx: Staging based on TNM criteria after full-body exam ® surgical excision, cryotherapy, radiation, Mohs Surg, topical 5-fluorouracil per staging
- Prog: 5-y cure rate >90%, 1% mortality rate, tumor staging correlates w/ recurrence & metastasis
Melanoma (NEJM 2006;355:51)
- Definition: Arises from epidermal melanocytes, most fatal form of skin cancer
- Epidemiology: 7th most common form of cancer in women
- Risks: Age, race, UV light exposure esp acute & intermittent, atypical nevi, high nevus count, MRAT: www.cancer.gov/melanomarisktool/
- Prevention: Insuff evid to recommend universal screening by USPSTF, but remain High-risk pts ® yearly screening from a dermatologist
• Clinical manifestations:
Superficial spreading melanoma: 70% of all melanomas, variably pigmented macules, irreg borders
Nodular melanoma: 15–30% of all melanomas, darkly pigmented, pedunculated nodules
Lentigo maligna melanoma: Begins as brown macule that grows to be darker, asym, & have raised areas
Acral lentiginous melanoma: <5% of all melanomas, most common form of mela- noma in darker-skinned people, most commonly on palms of hands & soles of feet
ABCDE: Asymmetry, border irregularities, color variegation, diameter >5 mm, evolving lesion (Dermatology 1998;197:11). Sens 97% if single criterion met, 43% if all 5 criteria met. Spec 36% if single criterion met, 100% if all 5 criteria nml.
Glasgow criteria: Referral if 1 major criterion, presence of minor criteria rein- forces need for referral
Major: Change in size or new lesion, change in shape, change in color
Minor: Diameter >6 mm, inflammation, crusting or bleeding, sensory change
Ugly duckling sign: Used to observe a pt w/ multi nevi, refer if a pigmented lesion appears different than the surrounding lesions
- Tx: Staging based on tumor thickness, mitotic rate, & ulceration ® wide local excision, LN excision, & adjuvant immunotherapy
- Prog: Based on tumor thickness (J Clin Oncol 2009;27;6199)
| Melanoma prognosis by tumor thickness | ||
| Tumor stage | Invasion thickness | 10-y survival rate |
| T1 | <1 mm | 92% |
| T2 | 1.01–2 mm | 80% |
| T3 | 2.01–4 mm | 63% |
| T4 | >4 mm | 50% |
| From J Clin Oncol 2009;27:6199. | ||