Skin cancer in Australia: What you should know.

BCC stands for Basal Cell Cancer. It is the commonest type of skin cancer. Outside of extremely rare cases involving advanced and neglected tumours, they do not spread to other organs.  BCCs will slowly grow like rot and can eventually break down your skin, but they won't kill you. "Cancer" is perhaps not the best term for this type of growth; "basal cell proliferation" or "basal cell growth" are more appropriate terms. The majority of these growths can be diagnosed without the need for biopsy. In-situ BCC is better known as "superficial BCC". ​ Large BCCs, particularly when of an "infiltrating" type are best removed surgically, but small diameter BCCs and thin BCCs can be easily removed without the need for cutting and stitching. For superficial BCCs, chemotherapy creams & photodynamic creams have the advantage of picking up invisible parts of tumour at the edges. These can easily be missed with surgery. Caution is advised with Moh's surgery for superficial tumours as unexpectedly large surgical defects can result.(https://onlinelibrary.wiley.com/doi/abs/10.1111/ajd.14535)

Bowen's Disease is an eponymous but misleading term for "squamous cell carcinoma in situ (SCC-in-situ) or "non-invasive SCC". It is not really a disease. SCC-in-situ usually presents as a flat red scaly patch in a sun-exposed site but is common on the lower legs of older people too. It's a type of growth where skin cancer cells are forming sheets in the uppermost layer of skin. The bottom line is that SCC-in-situ will not kill you. SCC-in-situ has a very low chance of transforming to a potentially dangerous "invasive SCC" (see below) and this is fairly obvious if it happens - a lump develops.  The vast majority of SCCs-in-situ can be removed without the need for cutting and stitching. Cautery, curettage, liquid nitrogen, as well as photodynamic & chemotherapy creams are effective.  As with superficial BCC, creams have advantages over surgery of picking up invisible parts of tumour at the edges.

Invasive squamous cell cancer (SCC) of the skin is a very common type of skin cancer that is easily removed/cured in the vast majority of cases. Invasive means that cells have reached the 2nd layer of skin. Invasive SCC usually presents as a lump in a sun-exposed area with some scaliness at the top of the lump. These tumours are generally excised, but if detected when they are small (<1cm diameter), they can be more simply removed by scraping them off the skin and burning the base ("curettage and cautery"). There is a broad spectrum of types of SCC - the types that have potential to spread are larger and often lack scaling.

This is another lesion that sounds more threatening than it is. The bottom line is that melanomas-in-situ do not kill! Some elaboration is given below to provide some context to this increasingly common diagnosis: ​ Melanoma-in-situ (MIS) is the term used when a pathologist can identify abnormal cells (akin to melanoma cells) in a lesion but they are confined to the uppermost layer of skin.  MIS is regarded as a possible precursor to "invasive melanoma", and the emphasis should be on possible.  It has become increasingly understood that many ?most MIS do not progress. There is no need to panic with this diagnosis. It is best removed because of the undefinable risk that it may change to an invasive melanoma if left. The pathologist cannot tell whether this was happening.  Intuitively, an MIS that is growing is probably more likely to convert to invasive melanoma than a MIS that is stable, but there is no data on this. ​ The diagnosis of MIS has become more common over the last 30 years and in Australia, they now outnumber true invasive melanomas by a factor of 2!  There are 2 reasons for this: Firstly it is because in more recent years, many more lesions are biopsied, and the second reason is that the histological criteria for the diagnosis have changed: Some lesions diagnosed as MIS today would have been classified as a type of mole 20 years ago. Here (https://www.nejm.org/doi/full/10.1056/NEJMsb2019760)is an article from the New England Journal of Medicine that highlights what has happened. The problems created by the escalation of melanoma diagnosis are outlined in this Australian paper: A Clinical Perspective of Melanoma Overdiagnosis.(https://onlinelibrary.wiley.com/doi/10.1111/ajd.14581) ​ If MIS is diagnosed then it is best cut out with a clear margin. In Australia, the guidelines are that MIS be cut out with a 5mm margin from the visible edge of the lesion so that clear histological margins are achieved. A 'grey' area is when clear histological margins have already been achieved on the biopsy. In this situation, there is no evidence that another excision will reduce the risk of recurrence or further harms.(https://jamanetwork.com/journals/jamadermatology/article-abstract/2838222?guestAccessKey=3b6509cc-8601-477b-adc2-e85690e83ac5&utm_medium=email&utm_source=postup_jn&utm_campaign=article_alert-jamadermatology&utm_content=etoc-tfl_&utm_term=101625)  In addition, there are no guidelines as to what the minimum histologic margin should be. Excision of MIS on the trunk or on a limb generally means a simple, straight-line cut, not a complicated one.   Some doctors may simply refer to melanoma-in-situ as being "melanoma" without further clarification. If you have been diagnosed with "melanoma" it might just be a MIS. It is best to ask.

Invasive melanoma (often referred to as malignant melanoma "MM") is a cancerous growth of melanocytes (cells which produce pigment). Invasive does not mean that the tumour has spread, it means that cells have penetrated into the 2nd layer of skin. MMs have far more potential to spread to other organs compared to other invasive skin cancers like SCC. The risk of spread correlates with the depth of the tumour, not the size on the surface. The majority of MMs are curable and early detection is the key. Surgery is the standard treatment.  MMs are usually, but not always pigmented. MMs that lack pigment ("amelanotic melanoma") can be difficult to diagnose by doctors and almost impossible to diagnose for those relying on artificial intelligence (such as "MoleMax" or smartphone apps).  The best "software" for detecting all types of MM has been, and still is..  the trained human brain.

"Melanocytic naevus" is the technical term for a harmless mole. It is a collection of cells that produce pigment (melanin).

Not all moles look perfect. A dysplastic mole is a mole that isn't perfect either to the naked eye or when examined under the microscope. There are many features that can make a mole "dysplastic". Some people have dozens of dysplastic moles. They cause no harm but the problem with having many of them makes the job of detecting a melanoma more difficult!  There is no evidence that dysplastic moles will turn into melanoma - this is a myth!

Melanomas should be cut out (excised) but for thin basal cell cancers (BCCs) and some superficial types of squamous cell cancer (SCC) there are other treatments which are just as effective.  The ideal management for BCC is to remove the tumour in its entirety with little or no scarring and without infection. It makes no sense to be left permanently disfigured from a treatment when an equally effective treatment with little or no risk of disfigurement could have been used. There are many situations where surgery is not the best option.  Non-surgical treatment options include curettage, photodynamic therapy, chemotherapy creams, or freezing (cryotherapy). Complete removal of thin BCCs following these treatments can  be verified using highly sensitive imaging technology known as optical coherence tomography (OCT). (Ref)(https://www.jaad.org/article/S0190-9622(23)01196-9/fulltext). ​ The cosmetic benefit of a non-surgical treatment can be huge. Of all treatments for BCC, it is photodynamic treatment (PDT) that has the least likelihood of scarring. Photodynamic treatment also has a mode of action that makes infection extremely unlikely.   We favour biphasic PDT as the treatment of choice for most superficial or thin BCCs in cosmetically sensitive sites. We will excise a BCC if that is your prefered treatment or when less-invasive treatment is not suitable.

Many BCCs and superficial squamous cell cancers (SCCs) are suitable for non-surgical treatment. If the skin cancer is fairly flat then a topical treatment treatment may be all that is required. If it is raised but ≤ 1 cm diameter and clearly demarcated, then it can be removed by scraping it off and cauterising the base (curettage & cautery).  Some clinics will not offer these treatments. Some will only discuss cutting and stitching. There are several reasons for this, but surgery is far from ideal when protocols dictate that the visible cancer should be cut out along with a 4-5 mm margin. This means for example, that if you have a superficial skin cancer on your face which is only 2 mm wide, you will potentially be left with a surgical defect which is over 1cm wide.  On sites like noses and foreheads, this means you will need a skin graft or other complicated repair, and this brings additional risks of infection and permanent disfigurement, as well as being costly. ​ Our aim is to inform you of more-sophisticated, less-invasive options when they are appropriate. We can assess tumour margins and suitability for non-invasive removal with OCT imaging. We can still excise a skin cancer if surgery is the best option, and this can be guided by the imaging so we don't cut any wider than needed.  ​ Please phone us for advice.

The OCT imaging technology can also be used to verify clearance of skin cancer. Scanning can be done once the treatment wound has healed. It can be used following any non-invasive treatment or following curettage (see before and after scans of BCC removal in the image scroll here)(https://www.northwestderm.com.au/non-surgical-skin-cancer-treatment). OCT can also be performed following surgical removal. This is reasonable when the pathology report shows peripheral margins are involved or the clearance is very narrow. It is important to note that whilst "clear margins" following surgical removal is good news, it is no guarantee that the tumour has been completely removed.