We take for granted the important task that the skin performs for our body. It protects us from external pathogens, regulates body temperature , filters the absorption of the sun’s rays and allows a correct hydro-saline balance with the outside.

We owe a lot to our skin: this thin and resistant elastic shield has in fact an active role for our immune system  whose specialized cells, interacting with each other, are a valid defense tool.

Precisely the continuous exposure to radiation, toxic substances and other mutogenic factors can determine the onset of skin tumors which , the data of the Italian Cancer Registries Association ( Airtum ) confirm, are the most common among oncological pathologies .

We talked about it with Mario Santinami , director of the complex structure of general surgery with oncological address 4 (Melanomas and Sarcomas) of the National Cancer Institute of Milan .

Why are skin cancers the most common?

Non – melanoma skin cancers are among the most common cancers of all: according to the Airtum registries they are in first place among men (15.2% of all cancers) and second among women after breast cancer (14.8 % of all cancers)

On average every year there are about 120 cases of non-melanoma skin cancer per 100,000 men and about 90 cases per 100,000 women .

One of the main risk factors is exposure to ultraviolet rays (UVA and UVB) which derives mainly from the sun, but also from sunbeds and sun lamps which must therefore be used with extreme care. 

The skin, being an organ more immediately in contact with the external environment, is more subjected to direct environmental damage , and this may be the cause of the high number of skin cancers compared to cancers that originate in other organs.

What are the most common types of skin cancer?

Skin cancers proper, with the exception of skin-onset melanoma, include lymphomas , cancers of the skin adnexa , Merkel’s carcinoma and other rare skin-onset histotypes, but mainly refers to squamous cell carcinomas (also called squamous or squamous cell carcinomas ) and basal cells.

> Basal cell and squamous cell carcinomas are the two most common histotypes of human cancers and, despite the increased attention to the prevention of the harmful effects of sunlight, these tumors are constantly growing. 

Since 1960, globally, there has been an annual increase in incidence ranging from 3% to 8%. The incidence of basal cell carcinoma increased by 10% per year, reaching a prevalence burden comparable to that of all cancers taken together.

Basal cell and squamous cell carcinomas develop mainly in the parts of the body most exposed to the sun: face, ears, neck, scalp, shoulders and back.

In particular, basal cell carcinoma represents 15% of all neoplasms and, although of a favorable prognosis, constitutes a public health problem: both because it is frequent and because it constitutes a significant care burden with significant economic repercussions. 

In the study population, the standardized incidence in males is 31.9 cases per 100,000 inhabitants , while in females it is 22.8 per 100,000 . 

> If we consider only the invasive forms, squamous cell carcinoma is the second most frequent skin cancer: its incidence in the study population for males is 4.2 cases per 100,000 inhabitants, in females 2.4 cases per 100,000 (average incidence rate).

More than half of the cases arise in males, with an M: F ratio of 1.32; the mean age is similar: 70 years in males and 69 years in females; the age group with the highest number of cases is that of elderly patients , between 75-84 years for both sexes. 

> Cutaneous melanoma is a growing cancer especially in Europe and North America, in addition to Australia where the incidence is the highest.

It is a very rare tumor in children and mainly affects around 45-50 years of age, although the average age at diagnosis has dropped in recent decades. In Italy, data from the Italian Cancer Registries Association for 2017 estimate about 7,300 new cases each year among men and 6,700 among women. 

The incidence is constantly growing and has even doubled in the last 10 years. And it makes up about 5% of all cancers that affect the skin.

What are the main causes?

As for basal and squamous cell carcinomas, the causes of onset are related to the genotype , the phenotype (phototype I-III) and environmental factors.

Ultraviolet UVB radiation causes direct damage to DNA and RNA with the formation of covalent bonds between adjacent pyrimidines, leading to the formation of toxic mutagenic compounds. 

Oncogenic viruses play an important role in the onset of skin cancers, as well as contact with arsenic, exposure to ionizing radiation, some  genetic abnormalities and a failure of the immune system have also been identified as risk factors .

In addition, smoking and some psoriasis treatments  can increase the risk of developing squamous cell carcinoma (especially of the lips in smokers). Regarding melanoma, the prevalent causal factors are genetic in nature.

However , there is a relationship between excessive exposure to ultraviolet light , which reaches us in the form of UVA and UVB rays, age and the risk of developing melanoma . 

Intermittent and prolonged exposure – especially in childhood and adolescence – is also associated with a greater risk: too much sun exposure can damage the DNA of skin cells and trigger tumor transformation. 

It is important to remember that solar lamps and beds are also sources of ultraviolet rays and must therefore be used with extreme care and without abusing them.

The “signs” to watch out for for a timely diagnosis of skin cancer

Skin cancers only rarely cause symptoms in the early stages .

It is important to periodically check the appearance of your moles by consulting your dermatologist and looking in the mirror or having a family member look at points that are not reachable from your own line of sight. 

The main sign of skin melanoma is the change in the appearance of a mole or the appearance of a new one. The characteristics of a mole that can indicate the onset of a melanoma are summarized in the abbreviation ABCDE :

• A for Asymmetry : in shape (a benign mole is generally circular or in any case rounded, a melanoma is more irregular);
• B as Edges : irregular and indistinct ;
• C as Variable color : (i.e. with different shades within the mole itself);
• D as Increasing dimensions : both in width and in thickness;
• And as the Evolution of the mole which, in a rather short time, shows changes in appearance. 

Other red flags that need to be evaluated by a doctor include a mole that bleeds , itches, burns or is painful, or is surrounded by a lump or red area.

As for skin cancers , squamous cell carcinomas  appear as nodules or areas with higher edges and a central depression , are sometimes ulcerated, rarely bleed, and usually have poorly defined margins.

As for basal cell carcinomas , on the  other hand, they appear as small pearly-looking nodules or as pink patches, slowly increase in size and can sometimes be pigmented and be mistaken for melanomas. 

In the presence of these signs, it is always recommended to consult a specialist .

What foods can remove the risk of skin cancer?

The Cancer Cure Foundation has decided to draw up a list of foods that help prevention : tapioca , for example, if taken from an early age can help the non-formation of melanomas. Its food use is mainly in the form of flour .

Rosemary , on the other hand, helps to increase the activity of detoxification enzymes : a rosemary extract, carnosol, according to what the organization reports, would inhibit the development of skin tumors.

These reports obviously require scientific validation