Surgery - Skin cancer (Squamous Cell Carcinoma)

Surgery - Skin cancer (Squamous Cell Carcinoma)
Introduction 
Skin cancer involving the epidermal keratinocytes. A squamous cell carcinoma known as Marjolin's ulcer develops in a region of skin that has been injured or irritated for a long time.

Etiology 

UV radiation from sunshine exposure, or actinic keratoses (sun-induced precancerous lesions), is the primary aetiological risk factor. The human papilloma virus, radiation, carcinogens (such as tar derivatives, cigarette smoke, soot, industrial oils, and arsenic), long-term immunosuppression (such as that experienced by HIV patients and transplant recipients), and DNA repair genetic defects (such as xeroderma pigmentosum) are some additional causes.

Epidemiology 
20% of skin cancers are the second most frequent cutaneous malignancy. This is a common occurrence in middle-aged and older light-skinned people. The incidence is roughly 1 in 4000. Men outnumber women 2-3: 1.

History 

Skin lesion, ulcer, bleeding repeatedly, or not healing at all.

Examination 

Variable appearance: Often on sun-exposed areas, ulcerated, hyperkeratotic, crusty or scaly, non-healing lesion. Feel for any localized lymphadenopathy.

Pathogenesis 

Bowen's disease manifests as solitary or many reddish-brown scaly patches. It is caused by intraepidermal carcinoma in situ, which is defined as intraepidermal proliferation of atypical keratinocytes when the basement membrane is intact. The malignant keratinocytes that cause squamous cell carcinoma enter the skin locally, move to nearby lymph nodes, and then migrate to distant organs like the liver and lungs.
The TNM system forms the basis for staging.

Investigations 

Skin biopsy: Determines whether a lesion is cancerous and sets it apart from other skin lesions.
Lymph node biopsy or fine-needle aspiration: Only required if metastases is suspected.
Scanning methods include PET, MRI, and/or CT.

Management 
Surgical: Curette, cryotherapy, cauterization, or photodynamic therapy may be adequate to completely remove a lesion in cases of Bowen's illness. When excising invasive squamous cell carcinomas, a suitable margin of 4 or 6 mm should be left (low- or high-risk lesions).
Mohs micrographic surgery involves precise margin excision and a histological evaluation to verify total excision. Can be applied to places like lips and the vicinity of eyes where extensive excisions are challenging.
A sentinal lymph node biopsy may be carried out in situations where there is a chance of metastasis.
When surgery is not feasible or for larger lesions, local radiation may be used (cure rate lower compared to surgery).
Medical: Intralesional interferons if alternative treatments are not feasible, or topical 5-fluorouracil for Bowen's disease. When a disease has spread, chemotherapy is used.

Complications 
When squamous cell carcinomas on sun-exposed skin are diagnosed, they are typically localized; however, one-third of those on the lips or lingual membranes have already spread.


Prognosis 
good as long as it is handled properly. The following are high-risk factors: (1) location of the tumor (lips, ears, and scar); (2) size of the tumor (>2 cm; lip and ear tumors measure 1.5 cm); (3) deep degree of invasion; (4) poorly differentiated; (5) perineural invasion; and (6) recurrent tumors.