Download Melanoma

Melanoma
Hai Ho, M.D.
Department of Family Practice
Epidemiology
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Sixth most common cancer
Incidence increases from 1/1500 in
1930 to 1/75 in 2000
1% of skin cancer but account for 60%
of skin cancer death
Risk factors?
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Sun exposure
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Intermittent intense exposure
Childhood
UVB > UVA – higher incidence near
equator
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Tanning bed
Clinical prediction rule
American Cancer Society’s
ABCDE
A
B
C
D
Melanoma could
occur in lesions
less than 6 mm
E
Elevation or Enlargement
by patient report
Sensitivity of ABCDE rule
If melanoma truly exists, the rule will
detect it 92-97% (average 93%) of the
time, when one criterion is met
Caution
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If none of the criteria is met, 99.8%
chance that the lesion is not a
melanoma (high negative predictive
value)
May miss amelanotic melanomas and
melanomas changing in size
Growth patterns
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Radial growth
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Lasts for months to years
Growth and regression due to restraint by
immunologic system
Horizontal and vertical growth
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More poorly differentiated
Produce nodule or mass
Superficial spreading melanoma
White =
regression
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50% of melanoma cases
Common in middle age
Radial spread and regression
Nodular melanoma
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20-25% of melanoma cases
Common in 5-6th decade
Vertical growth and no horizontal growth
phase
Lentigo maligna melanoma
Lentigo
maligna
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15% of melanoma cases
Elderly – 6-7th decade
Lentigo maligna
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Lentigo maligna
melanoma
Horizontal growth phase for years
Bizarre shapes from years of growth and regression
Transform to lentigo maligna melanoma
Acral-lentigious melanoma
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10% of melanoma cases
In palms, soles, terminal phalanges, and mucous membrane
Growth phase similar to lentigo maligna and lentigo maligna
melanoma
Aggressive tumor and early metastasis
Excisional biopsy
Preferred method – deepest level of penetration for staging
Punch biopsy
Stretch the skin
perpendicular to the skin line
Subcutaneous fats
Wound <4mm may not be sutured
Shaving
Never because prognosis and
treatment are based on the
level and depth of invasion
Pathology
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Depth of invasion
Growth pattern (nodular, superficial
spreading, etc.)
Margin status
Presence or absence of ulceration
Depth of invasion
Breslow
•Measure the actual thickness
•More reproducible and accurate
in determining prognosis
Clark
•Report by anatomical site
•Significant if tumor ≥ 1mm
Indications for regional node
biopsy
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Thickness 1-4 mm
Thickness < 1mm
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Has <10% of nodal metastasis  no biopsy
Ulceration, truncal location, and male gender,
either alone or in combination  consider
biopsy to evaluate nodal metastasis
Thickness > 4mm
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Has 65-70% distant metastasis  no biopsy
Histological examination of
nodes
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Reverse transcriptase polymerase
chain reaction (RT-PCR) assay detects
of tyrosinase messenger RNA, a
melanocyte-specific marker, in lymph
nodes with metastasis
Immunohistochemistry techniques
Staging
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Depth of invasion
Regional nodal metastasis
Distance metastasis
Survival rate
LDH
Prognostic indicator for
distant metastasis in stage IV
Cutaneous excision
Recommendations from Academy of
Dermatology
 A margin of 0.5 cm of normal skin is
recommended for in situ melanomas.
 A 1 cm margin is recommended for
melanomas <2 mm thick
 A 2 cm margin is recommended for
melanomas 2 mm thick
Other recommendations
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Surgical margin of 3 cm for T3 (2.1 to
4.0 mm) or T4 (>4 mm) primary tumors
No correlation between thickness >
4mm and surgical margin (Heaton et al.
Ann Surg Oncol 1998)
In >4mm thickness, outcome is
probably based more on regional and
distant metastasis
Head and neck melanomas
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Face and scalp – high recurrence rate
Complex regional node drainage
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Parotid and cervical lymphatics are common
sites of spread
Parotid node dissection – risk of CN VII injury
Limited skin – skin graft
Post-op adjuvant radiation for unsatisfactory
margin and desmoplastic neurotropic
melanomas
Subungual melanoma
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Fingers
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Amputation DIP
Cutaneous excision and skin graft for
proximal lesions
Toes
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Amputation at MTP
Plantar melanoma
Cutaneous excision with skin
graft due to lack of surplus skin
Positive sentinel nodes
Regional lymph node dissection
Noncerebral metastatic
melanoma
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Cytotoxic chemotherapy
Immunotherapy such as interferon
Pallative
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Radiation
Surgery
Cerebral metastatic melanoma
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Surgery
Whole brain radiation therapy
And/or stereotactic radiosurgery