Melanoma Flashcards
What type of growth phase do most melanomas begin with?
- horizontal growth phase
- this is where melanocytes form nests along the basal layer
- later they will migrate and form nests in the upper layers of the epidermis
- this growth can last 15 years
What is the second growth phase of melanomas called?
- vertical growth phase
- melanocytes descend across the basal lamina and into the dermis
- during this phase nodules can become raised on the skin’s surface
- can invade blood and lymphatics
Epidemiology
- 15 to 19 years, M:F equal
- 30 to 40 years, M:F 1:2
- 1 in 56 women and 1 in 37 men
- men predominantly on the trunk
- women mainly on the lower extremities
Risk for melanoma increases when?
- increased sun exposure (UVB)
- fair-skinned
- red haired, blue eyed (triple incidence)
- increased age (peak at 40 years)
- patients with melanoma have a 5% risk of developing a second melanoma
- patients with dysplastic nevus syndrome
- 8 times the risk if theres a family history
- linked to intense and intermittent sun exposure
ABCDEs of melanoma
Review this slide
What are the melanoma subtypes and their prevalences
- Superficial spreading (70%)
- Nodular (15-20%)
- Lentigo maligna (10-15%)
- Acral lentiginous (<5%)
Superficial spreading
AKA radical spreading melanomas
- intermittent sun exposure
- trunk and extremities
- occurs in 40-50 years of age
- slow evolution of change in a mole, followed by a period of rapid growth
Nodular
- appear at middle age (50s-60s)
- early vertical growth, raised, protrudes, bleeds easily
- can arise without pre-existing nevus
- face, chest, back
Lentigo maligna
AKA Hutchunson’s Freckles
- large, flat, tan with irregular border
- gets darker as it grows
- face, ears, arms
- chronic sun exposure
- 60s-70s
Acral lentiginous
- 35 to 60% asians, hispanics, African descent
- palms, soles, subungual areas
- average age is 60 years
- not linked to sun exposure
- dark brown or black flat spot
Diagnosis
- physical exam and history
- dermoscopy
- excisional biopsy
- FNA or SLNB and PET
- baseline CXR (lung mets)
- lab work (melanin in urine, blood including LDH for mets to liver)
- CT (chest, abdo, pelvis) thickness>4mm
- MR (mets to brain or spinal cord)
Routes of spread
- local-via satellite nodules, subcutaneous tissue
- lymphatic-local regional lymph nodes
- Hematogenous-liver, lung, bone, brain
- Rare-GI tract, adrenal gland
Micro staging systems
Review lecture notes
Clark’s-depth of invasion
Breslow’s-bulk of disease
TNM staging
Early stage: stages 0-2c
Locoregional: stage 3
Metastatic: stage 4
Review TNM staging notes
What is the primary treatment
Surgery
Small lesions (0-1.5 mm): 1 cm margin Intermediate lesions (>1.5-4 mm): 1-2 cm margin Larger lesions (>4 cm): 3 cm margin laterally and into fascia
What needs to be done to lymph nodes
Early stage-SLNB
Complete nodal dissection when lesions are between 1-4 mm because about 20% of patients are expected to have nodal mets (T2-T4)
Adjuvant treatments?
Typically, because recurrence is high
-RT, chemo or immunotherapy
immunotherapy
- 16% of metastatic melanomas may respond to immunological approaches
- BRAF inhibitors
- Interleukin-2: 25% response rates, high costs and toxicity
- Interferon: delays recurrence but toxic
When is RT used
- May be useful as a primary or adjuvant modality when patients refuse surgery or are debilitated
- Multiple large lymph nodes
- Extracapsular spread
- Local recurrence in a previously dissected lymph node basin
- Metastatic disease
- Recurrent disease
- Stages 3c or 4
RT prescription
55 Gy/ 30 fractions=moderate to large inner canthus, eyelid, nasal or pinna lesions
45 Gy/ 15 fractions=moderate-sized lesions on free skin or postoperative treatment to moderate-sized cancer on “free” skin with positive margins
40 Gy/ 10 fractions, 30 Gy/ 5 fractions, 20 Gy/ 1 fraction=high cure rate for small lesions but cosmetic results less than optimal after 5 years
RT for palliative cases
POP (6 or 15 MV)
2000 cGy/ 5 fractions
3000 cGy/ 10 fractions
SBRT: bone mets
SRS solitary mets (brain)
-16-25 Gy to 80% isodose
Acute and chronic side effects of RT
Acute:
- erythema
- dry/moist desquamation
- epilation
Chronic:
- decreased or absence of sebaceous and sudoriferous gland function
- fibrosis
- hypersensitivity
- telangiectasia
