People with non-melanoma skin cancer may have questions about their prognosis and survival. Prognosis and survival depend on many factors. Only a doctor familiar with a person’s medical history, type of cancer, stage, characteristics of the cancer, treatments chosen and response to treatment can put all of this information together with survival statistics to arrive at a prognosis.
A prognosis is the doctor’s best estimate of how cancer will affect a person, and how it will respond to treatment. A prognostic factor is an aspect of the cancer or a characteristic of the person that the doctor will consider when making a prognosis. A predictive factor influences how a cancer will respond to a certain treatment. Prognostic and predictive factors are often discussed together and they both play a part in deciding on a treatment plan and a prognosis.
Prognostic and predictive factors for non-melanoma skin cancer can vary depending on whether the person has basal cell carcinoma or squamous cell carcinoma.
Basal cell carcinoma (BCC)
BCC may be defined as low or high risk based on the potential for the tumour to recur or metastasize. The following factors are used to help determine whether BCC is low or high risk:
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Tumour size | Larger primary BCC tumours are more high risk because they are more likely to recur. |
Tumour location | Tumours involving cartilage or bone are high risk because they are more likely to recur. These include tumours on the nose, eyelid, groove of upper lip, middle to lower chin, cheek, forehead, scalp and ear, hands, feet or genitalia. |
Tumour borders | Tumours with poorly defined borders are considered high risk. Tumours with well-defined borders are low risk. |
Recurrent disease | Recurrent tumours are high risk compared to primary tumours. |
Immunosuppression | People with a suppressed immune system have a poorer prognosis and a higher risk of metastasis. |
Prior radiation therapy | Tumours that occur at a site of prior radiation therapy are high risk. |
Tumour subtype | Nodular and superficial subtypes are low risk. Certain subtypes, such as morpheaform (sclerosing), infiltrative or micronodular, are high risk because they tend to be more aggressive and have a higher risk of recurrence. |
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Squamous cell carcinoma (SCC)
SCC may be defined as low or high risk based on the potential for the tumour to recur or metastasize. The following factors are used to help determine whether SCC is low or high risk:
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Tumour size | Tumours larger than 2 cm in diameter on the trunk or extremities have a higher risk of recurrence. Tumours larger than 1 cm in diameter on the cheeks, forehead, neck or scalp have a higher risk of recurrence. |
Tumour location | Tumours on mucosal surfaces (lip and genitals) and ears have a higher rate of metastasis. Tumours involving cartilage or bone are high risk because they are more likely to recur. These include tumours on the nose, eyelid, groove of upper lip, middle to lower chin, cheek, forehead, scalp and ear, hands, feet or genitalia. |
Tumour borders | Tumours with poorly defined borders are considered high risk. |
Recurrent disease | Tumours that recur locally have an increased risk of metastasis. |
Immunosuppression | People with a suppressed immune system have a poorer prognosis and a higher risk of metastasis. |
Prior injury | Tumours that occur on sites of prior injury (scars, burns, areas that received prior radiation therapy) have a higher risk of metastasis. |
Chronic inflammation | Tumours that occur at a site of chronic inflammation have a higher risk of metastasis. |
Rapid growth | Tumours that grow rapidly are high risk. |
Tumour subtype | Adenoid or desmoplastic subtypes are more high risk than other subtypes. |
Grade (differentiation) | Moderately and poorly differentiated tumours have a greater risk of recurrence. |
Depth of invasion | Tumours deeper than 4 mm are high risk because they tend to recur and metastasize more often. Tumours that invade muscle, bone or other subcutaneous tissue have a poorer prognosis. |
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