The Medicolegal Challenges of Skin Cancer Management
Skin cancer is one of the commonest forms of cancer, currently accounting for around one-third of all cancers annually, and the incidence is rapidly increasing. Fortunately, effective treatments are available and the risks of mortality and other complications associated with most types of skin cancer are extremely low. However, some challenges remain.
The majority of patients with skin tumours develop non-melanoma skin cancers, a group that includes basal cell carcinoma, the commonest of all skin cancers, and squamous cell carcinoma. Non-melanoma skin cancers are rarely fatal. Basal cell carcinomas usually occur on the face or the backs of the hands. Usually, growth is slow and spread is minimal, with metastasis to other areas of the body being rare.
Around 20% of all cases of non-melanoma skin cancer are squamous cell carcinomas. As these usually arise as the result of a high lifetime exposure to the sun, not surprisingly the incidence is much higher in older patients. The majority of these tumours occur on the head and neck, although the hands and forearms, upper trunk and lower legs are also common sites. Squamous cell carcinomas range in size but often increase in size fairly rapidly over the course of a few months. There is also a small risk of metastasis, particularly to the lymph nodes, lungs and liver. Once metastasis has occurred, the cure rate markedly decreases.
In contrast, malignant melanomas account for around 75% of all deaths from skin cancer. Mortality rates are higher in men and in black patients. This may be due to an increased likelihood of tumours developing in less easily observed areas and diagnosis occurring at a later stage. Melanomas are commoner in younger patients, with the peak age being between 20 and 45 years. Around 60% of malignant melanomas are thought to arise from skin lesions called actinic keratoses, which are not malignant themselves but do provide an indication of a patient’s cumulative exposure to ultraviolet light and thus their overall skin cancer risk. Although the risk of any individual keratosis progressing to malignancy is less than one per 1000 per year, removal is usually indicated. A rare form of malignant melanoma develops from lentigo maligna, which may exist in a relatively benign form for many years, or even decades, before it invades the dermis. Again, removal is the preferred option.
Early detection and treatment are associated with an improved prognosis, but the diagnosis of skin cancer can be difficult. For example, melanomas are often misdiagnosed, as they resemble a number of benign lesions including blood blisters, haemangiomas, nevi, seborrheic keratoses and solar lentigines. Pain, erythema, ulceration, hyperkeratosis and an increase in the size of an existing nevus or actinic keratosis may indicate progression to malignancy. Detection rates for skin cancers have been improved by the development of the ABCD checklist. The presence of one or more of Asymmetry, Border irregularity, Colour variation and Diameter above 6mm could indicate the presence of malignancy. However, while a preliminary diagnosis may be possible from the appearance of the tumour, definitive diagnosis by a full-thickness excisional skin biopsy is vital before treatment commences. As diagnosis relies on the overall lesion architecture, incisional and punch biopsies may not be sufficient if the areas examined do not contain the most diagnostically reliable tissue.
Cryotherapy with liquid nitrogen is the usual method of removal for superficial tumours and actinic keratosis. Curettage, either alone or in combination with cryotherapy or electrodessication may also be used. However, in basal cell carcinomas, lower cure rates are seen when these techniques are used on sclerosing and recurrent tumours. Well-differentiated tumours can be surgically excised, a procedure which gives an almost 100% cure rate. When tissue removal must be minimised, either for cosmetic reasons or to preserve function, a technique called Mohs’ micrographic surgery may be used. This involves gradual excision of the lesion using serial frozen section analysis and precise mapping of excised tissue, until a tumour-free layer is reached. Radiation therapy is also useful for cases where the preservation of function or cosmetic appearance is important, for patients who refuse surgery, or when an adjunct to surgery is required in high-risk tumours. However, due to the risk of radiation-induced carcinoma, this modality is usually reserved for patients aged over 60 years.
Other complications associated with treatment include haemorrhage, dehiscence, graft necrosis and infection, although none of these is very common. However, certain patient factors, such as smoking and the presence of conditions like diabetes or immunosuppression, increase the risks. Furthermore, many skin cancer patients are elderly and more likely to have comorbid diseases. Despite this, the use of prophylactic antibiotics is generally reserved for high-risk cases and decided on a case-by-case basis.
Despite the known benefits of early diagnosis, mass screening programs have generally not proved useful. Instead, public education on the risk factors for skin cancer and the importance of measures to prevent sunburn is more beneficial, as patients who receive this information are more likely to seek medical attention for suspicious lesions. However, high-risk patients, such as those with a history of skin cancer or atypical mole syndrome, should always receive periodic screening.
Further reading:
Arguello-Guerra, L., Vargas-Chandomid, E., Díaz-González, J. M., Méndez-Flores, S., Ruelas-Villavicencio, A., & Domínguez-Cherit, J. (2019). Incidence of complications in dermatological surgery of melanoma and non-melanoma skin cancer in patients with multiple comorbidity and/or antiplatelet-anticoagulants. Five-year experience in our hospital. Cirugia y Cirujanos, 86(1), 15–23. https://doi.org/10.24875/CIRUE.M18000003
Jerant, A. F., Johnson, J. T., Sheridan, C. D., & Caffrey, T. J. (2000). Early detection and treatment of skin cancer. American Family Physician, 62(2), 357–382.
