melanoma hai ho, m.d. department of family practice
TRANSCRIPT
Melanoma
Hai Ho, M.D.
Department of Family Practice
Epidemiology
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?
Sun exposure Intermittent intense exposure Childhood
UVB > UVA – higher incidence near equator
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
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
Radial growth Lasts for months to years Growth and regression due to restraint by
immunologic system Horizontal and vertical growth
More poorly differentiated Produce nodule or mass
Superficial spreading melanoma
50% of melanoma cases Common in middle age Radial spread and regression
White = regression
Nodular melanoma
20-25% of melanoma cases Common in 5-6th decade Vertical growth and no horizontal growth
phase
Lentigo maligna melanoma
15% of melanoma cases Elderly – 6-7th decade Lentigo maligna
Horizontal growth phase for years Bizarre shapes from years of growth and regression Transform to lentigo maligna melanoma
Lentigo maligna
Lentigo maligna melanoma
Acral-lentigious melanoma
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
Wound <4mm may not be sutured
Subcutaneous fats
Stretch the skin perpendicular to the skin line
Shaving
Never because prognosis and treatment are based on the level and depth of invasion
Pathology
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
Thickness 1-4 mm Thickness < 1mm
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 Has 65-70% distant metastasis no biopsy
Histological examination of nodes
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
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
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
Face and scalp – high recurrence rate Complex regional node drainage
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
Fingers Amputation DIP Cutaneous excision and skin graft for
proximal lesions Toes
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
Cytotoxic chemotherapy Immunotherapy such as interferon Pallative
Radiation Surgery
Cerebral metastatic melanoma
Surgery Whole brain radiation therapy And/or stereotactic radiosurgery