“After skin cancer, the risk of a second skin lesion – carcinoma or melanoma – is significantly increased”, Prevents Prime Maubec, dermatologist at the Avicenne Hospital (Bobigny, AP-HP) and specialist in skin cancers for the French Dermatology Society (SFD).
Precisely, around 5 % of patients who presented melanoma will develop a second during their lifetime (1). After a basal carcinoma (CBC), the risk of CBC or epidermoid carcinoma (CE) reaches 36 % at five years (2). And a mélanoma -plated risk was observed after an epidermoid carcinoma and after a CBC (3). A meta-analysis finds, twenty years after a melanoma, a risk of developing new skin cancer of 5 % for a second melanoma, 14 % for a CBC and 4 % for a CE (4).
A risk linked to solar exposure
The risk of second primitive skin cancer is multifactorial. It can exceptionally be due to predisposition changes, such as those of the PTCH1 gene, observed in the case of bascellular nevomatosis (gorlin syndrome), which promote the appearance of multiple CBCs, or CDKN2A gene, in case of multiple sporadic melanomas or family melanoma. It also depends on aging, on individual characteristics (very clear skin, high number of beauty grains, history of secondary burns to a photoxual photo, especially during childhood) but it is essentially carried by a societal behavior of exposure to ultraviolet, natural or artificial.
The corollary is that daily photoprotection reduces, by 39 % in the case of CE, the risk of new lesions (5). This is not valid for the CBC, whose pathophysiology seems to depend on the exposure cumulative UV since childhood.
It is still necessary that patients adopt good practices. In an Australian study, a year after treatment of skin carcinoma, only 62 % of patients used sunscreen screens (6). “In this same context, we noted that only 59 % of patients avoided the sun in the hottest hours, 45 % wore a hat, 28 % of covering clothes, and 35 % regularly used a high index sunscreen (7), reports Pr Maubec. Like what, general advice is not enough. Awareness must be individualized and the therapeutic education tools have their place. »»
A reduction under conditions
The first years, the frequency of follow -up is adapted to the risk of relapse of skin cancer. Beyond that, if indicated, follow-up will most often be annual, dedicated to screening.
• After a CBCthe surveillance offered is generally annual, for at least five years. Beyond that, it can be interrupted in the absence of other history of skin cancer, or maintained at an annual rate otherwise.
• After a CEthe follow -up depends on the risk of recurrence (2025 algorithm of the Cancer and skin group of the SFD), with annual follow -up for at least three years for those at low risk and, for those at high risk, closer monitoring, every three to six months for three years, then at least annual follow -up adapted according to the field. “Thus, a patient who presented several epidermoid carcinomas with many actinic keratoses require regular dermatological monitoring, in the half-year-old, illustrates the pr maubec. On the other hand, a patient with a single lesion-even at high risk-can benefit, beyond the period of three years of follow-up (where 95 % of the relapses arise), a spacing of the follow-up adapted to the context. »»
• After a melanomaafter three years of quarterly semi -annual follow -up, surveillance, proposed for life, varies between every six months and every year, modulated according to individual risk factors. In patients who have already had one or more melanomas and having atypical Nævi syndrome, surveillance twice a year may be maintained. This will also be semi-annual for life in the event of genetic mutation of predisposition to melanoma (CDKN2A, CDK4) or multiple family history of melanoma.
Finally, in the event of long-term immunosuppressive treatment and in transplanted patients, skin carcinomas, especially epidermoids, justify reinforced surveillance based on the Suntrac score: every three to six months, including beyond the CAP of three years, due to an increased probability of developing clinically more aggressive forms, with greater invasive or metastatic potential (8).
In practice, the demography of dermatologists no longer allows them to ensure regular monitoring of all these patients. “General practitioners could participate in this follow -up and familiarize themselves with dermatoscopy, very useful in the event of suspicious lesion to sort through a bascellular carcinoma – which evolves over several years – and a nodular melanoma – which progresses in a few weeks”, underlines Pr Maubec.
(1) Schmid-Wendtner MH, et al. Br J Dermatol. 2001Â Dec;145(6):981-5
(2) Flohil SC et al. Eur j cancer. 2013 Jul; 49 (10): 2365-75
(3) Rees JR et al. PLoS One. 2014Â Jun 17;9(6):e99674
(4) Van der Leest RJ et al. J EUR Acad Dermatol Venereol. 2015 Jun; 29 (6): 1053-62
(5) Green A et al. Lancet 1999; 354:723-9
(6) Robinson JK. Arch Dermatol 1990; 126: 477-81
(7) Meyer N et al. J Eur Acad Dermatol Venereol. 2007;21:520-5
(8) Jambusaria-Pahlajani A et al. Transpl Int. 2019Â Dec;32(12):1259-67
