CONGRESS REPORT OF THE 5TH NATIONAL CONGRESS OF THE BULGARIAN SOCIETY FOR DERMATOLOGIC SURGERY, SOFIA, 11TH MARCH 2023 WITH MAIN TOPICS: NITROSAMINES AS MOST POWERFUL TRIGGER FOR SKIN CANCER DEVELOPMENT AND PROGRESSION/PERSONALISED ONE STEP MELANOMA SURGERY AS POSSIBLE SKIN CANCER TREATMENT OPTION

Deciphering the mutational pattern of skin tumours, remains a major challenge for clinicians and researchers. Over 80% of mutations in tumours are acquired, which in practice also means preventable. The surgical treatment of skin cancer and cancer in general is a worldwide, unsolved but at the same time not unsolvable problem. The problem concerning the dilemma of acquired mutations lies in the circumstance of their being allowed and subsequently treated. A more logical solution would be to eliminate the problem by making contact with mutagens in drugs public, clarifying it, studying it in detail and definitively stopping it. At present, there is an alarming and unexplained tendency worldwide : 1) Potential acquired mutations, caused in all probability by contact with known exogenous mutagens- the nitrosamines in most commonly prescribed drugs, are allowed to occur. 2) And subsequently, the diseases generated by them- treated (at a later stage) by multiple surgical interventions and unjustifiably expensive targeted therapy; 3) Mutagens - such as nitrosamines for example, to be in a permissive or possibly permissive availability regime. Moreover, this permissible availability turns out to be ubiquitous and affects the most common medicines worldwide: metformin, ranitidine, propranolol, rifampicin, irbesartan, olmesartan, valsartan, telmisartan, eprosartan, losartan, ACE inhibitors, thiazide diuretics, etc. In certain geographical regions, there is almost no patient taking this type of medication who has not had at least one tumour detected. These significant correlations (nitrosamines/cancer) are labeled by the regulatory institutions as possible, probable, or not currently relevant. But in spite of ˝this inconclusiveness˝, the drugs, containing nitrosamines, are withdrawn from the pharmaceutical market: quickly and quietly, despite the fact that ˝they did not pose a threat˝. The FDA was the only organization and the most important regulatory body worldwide, which lifted the veil from this ominous picture back in 2018: nitrosamines in blood medicines and cancer risk. Unfortunately, at the moment, the problems with this issue are proving to be more than the solutions, and at the same time it remains completely unclear who is to blame for this 'sporadic contamination': the packaging of the drug, the humidity in the rooms where the preparations are stored or the synthesis process itself - the explanations are divergent, the responsibility is blurred. This fuzzy liability does not affect the manufacturers and distributors of the preparations/nitrosamines themselves in the manner required by law for this (mis)act. The Bulgarian Society of Dermatological Surgery remains to be the only organization worldwide that for the 5th consecutive year continues to seek solutions to the above-mentioned problems by: 1) Officialising all cases of skin tumors (but not only) occurring after intake of nitrosamine-contaminated drugs, 2) also officialising a significant number of cases of patients with cutaneous melanomas treated by the one-stage surgical removal method within one surgical session (OSMS). The main priorities of the organization remain: 1) the complete elimination of nitrosamines from drugs worldwide, 2) the optimization of melanoma surgical treatment guidelines with the goal of treatment within 1 surgical session: for thin melanomas, dysplastic nevi and melanoma in situ, a surgical margin of safety of 1 cm in all directions and without detection and removal of the draining sentinel lymph node. Whereas for medium and thick melanomas, the focus should be directed to the following recommendation: 2 cm surgical margin of safety plus detection and removal of the draining lymph node within one surgical session. The indication for the surgical removal of these lesions should be made on the basis of radically different criteria from those used to date by the AJCC/EJC, namely: based on 1) clinical presentation/ clinical morphology, 2) dermatoscopic finding, and if there is a melanoma suspected lesion with possible tumour thickness greater than 1 mm , 3) ultrasonographic measurement for preoperative determination of tumor thickness should be additionally performed. The methodology is applicable in up to 80% of cases, excluding only some rare findings such as: amelanotic cutaneous melanomas, cutaneous melanomas with regression zones or those with localization in the neck and head. However, after careful individual assessment and a subsequent selected approach, even these exceptions could be included in the innovative algorithm for one step surgical removal of cutaneous melanomas. The resulting problems of not resolving these two dilemmas could lead to: 1) Generation of skin cancer (but not only), through the availability of nitrosamines in drugs. 2) Unnecessary and stressful /surgeries for the patients- 2 in number, which not infrequently lead to complication of their status (due to delay of histopathological analysis/ desire for second opinion/ delay regarding the timeframe for the second surgical intervention/ uncertainty regarding the resection lines within the first intervention/ failure to respect the recommended surgical security resection margins already within the first surgical session, etc.). 3) Huge additional costs to health care systems on the order of probably/roughly calculated about $50 billion per year. Resolution of these two dilemmas would likely result in a dramatic drop in cancer incidence worldwide and a significant improvement in the effectiveness/efficiency of surgical treatment for cutaneous melanoma.