Skin and genitourinal Cancers Flashcards
What are the four types of melanoma and the associated demographics / risk factors?
Superficial spreading
- Typically younger pts
- lower sun exposed areas
- Often associated with precursor nevus
- more associated with BRAF mutations
Lentigo maligna
- typically older pts
- High sun exposed areas
- Usually ass with actinic (solar) keratosis
- Rarley associated with BRAF mutations
Desmoplastic melanoma
- Older pts, very sun exposed skin
- High tumour mutational burden, responds well to immunotherapy
Non solar exposure related melanoma
- Eg uveal melanoma, acral melanoma, mucosal melanoma, melanoma in blue nevus
Melanoma risk factors?
In order of most risk to least risk
- Xeroderma pigmentosum (east asian and subcontinent)
- Prievious melanoma
- High nevus count
- Red hair and blue eyes
- Male sex
- first degree relative with melanoma
- Sun exposure - >10 sunburns <13yrs old
What are acceptable margins for a <1mm thickness, 12mm thickness, and >2mm thickness melanoma?
<1mm thickness - 1cm margin
1-2mm thickness 1cm or 2cm margins (evidence for both)
>2mm thickness - 2 cm margin
What has a worse prognosis? Stage 2C and stage 2B melanoma or stage 3A melanoma?
Stage 2B and 2C have worse prognosis that 3A
- it is now routine to offer adjuvant immunotherapy to stage 2C and 2B
Which stages of melanoma are offered adjuvant immunotherapy? and what agents are used?
Stage 2B and 2C
Stage 3B-C
PD1 or PDL1 inhibitors are used primarily, usually pembrolizumab or nivolumab
What systemic therapies are used for melanoma?
Immunotherapy
- PD1 and PDL1 inhibitors
Targeted therapies
- RAF/MEK inhibitors
Chemotherapy
- Dacarbazine (historically, but not so relevant anymore)
Give an example of a common mutation in melanoma?
B-RAF mutation is found in 40-50% of melanomas
- more common in superfical spreading type
- V600E in 3/4 of these, V600K in 1/5 of these
- Not prognostic but predictive of response to RAF/MEK inhibitors
What is the mechanism of action of BRAF mutation in melanoma
RAF is park of the RAF/MEK pathway
- activating mutations in b-RAF results in downstream signalling (MEK)
What are some common RAF inhibitors used in melanoma?
Dabrafenib, Vemurafenib, Encorafenib
RAF inhibitor toxicities?
Rash
Fatigue
Photosensativity rash
Arthralgias
SCC (in pts with activating RAS mutations)
What are some common MEK inhibitors used in melanoma?
Trametinib, Cobimetinib, binimetinib
MEK inhibitor toxicities?
Rash
Fatigue
Diarrhoea
Arthralgias
Peripheral oedema
No increase in SCC as inhibits down stream MEK
Why is immunotherapy better for intracranial melanoma mets compared to other systemic therapies?
Immunotherapy trains the immune system outside of the blood brain barrier, which results in enhanced immune response in the brain
Other systemic therapies have trouble crossing the blood brain barrier
Combined CTLA4 and PDL1 blockade is preferred
Mechanism of LAG3 inhibition in melanoma?
LAG 3 is a cell surface molecule on immune cells
- It negatively regulates T cell proliferation - and effector T cell function
- It is upregulated in melanoma
- It is distinct from the PD1 pathway
LAG3 inhibition works synergistically with immunotherpy
Give an example of a LAG3 inhibitor?
Relatlimab
How is metastitic melanoma treated?
Single agent immunotherapy usually
- Can consider adding LAG3 inhibitor Relatlimab given well tolerated
- Can consider ipilimumab + nivolumab in those with poor prognosis, liver mets, Braf positive disease, mucusal/acral melanomas
Immunotherapy generally preferred over targeted therapies RAF/MEKi even if BRAF positive
- RAF/MEK result in more rapid reduction in tumour size so can consider in pts who need rapid tumour size reduction initially (ie mass effect)
What are the two main types of keratinocyte carcinomas?
Basal cell carcinoma
Squamous cell carcinoma
Local therapies ar the mainstay of treatment for keratinocyte carcinomas. What are some local therapies types?
- Surgery (Mohs surgery, Standard Excision)
- Radiation therapy for non surgical candidates
- Topical or photodynamic therapy for in situ or low risk cancers
What is the main molecular pathway in BCC?
BCCs usually arrise from dysfunction in the hedghod signalling pathway
Explain the Hedghog pathway in BCC?
Membrane PTCH1 normally suppresses membrane SMO. Without this suppression SMO leads to downstream signalling
In BCC, PTCH1 is mutated. leading to SMO activation and downstream signalling. Drugs that suppress SMO directly can be used
What are some drugs that suppress SMO for BCCs?
Vismodegib, Sonidegib
General treatment for Met cutaneous SCC?
PD1 inhibitors
- gold standard for tumors that cannot be treated with local therapy (surg, radio) alone
- Cemiplimab (noval PD1i), pembrilizumab
Platinum based chemo - can still be effective for distant mets
General treatment for locally advanced cutaneous SCC?
Neoadjuvant therapy, then definitve surgery
- neoadjuvant with noval PD1i Cemiplimab
What is the precursor leision to cutaneous SCC?
Actinic keratosis
What is treatment for actinic keratosis?
Cryotherapy OR topical therapies (if cosmetic region)
- cosmetic therapies inc flurouracil, imiquimod
What are merkel cells in the skin?
they are the mechanoreceptors in the top layer of skin
Treatment of merkel cell carcinoma?
Highly immunogenic cancer, so treat with immunotherapies
Does PSA screening work? what is the main downside of PSA screening?
Yes it does work
Main down side is the opportunity cost - more medical intervention for pts with positive result, many people would not have had symptoms or effects of PrCa in their life
Risk stratification guide Pr Ca Rx. How is prostate cancer risk stratified?
Risk stratification, then treat by risk category
- risk stratification based on tumour grade, size and extension (MRI), volume (no. core Bx involved), PSA lvl, predicted survical from other co-morbidities
How is low risk Pr Ca treated?
Observation
How to determine of Pr Ca is organ confined or metastatic?
CTAP, PSMA PET imaging