Treatment and follow-up
Treatment of SCC in situ differs from that of other SCCs (for which the treatment of choice is usually excision). The treatment options for SCC in situ, especially clinically thin lesions, are similar to those used for solar or actinic keratoses (eg liquid nitrogen cryotherapy, curettage, topical field treatments).
The choice of treatment depends on patient and lesion factors (eg thickness and size of lesion, site and extent of lesions, patient age, comorbidities [especially immunosuppression], patient preference, treatment cost).
Cryotherapy, curettage and cautery are suitable for small well-demarcated lesions; however, these treatments should be used with caution at sites of poor wound healing (eg distal lower limbs in older people).
Topical field treatments (including photodynamic therapy) are appropriate for SCC in situ at sites of poor wound healing, although ulceration and delayed healing can also occur with these options.
Topical field treatment options for SCC in situ include:
1fluorouracil 5% cream topically, once or twice daily for 2 to 4 weeks. If the lesion has not completely resolved after the skin heals, repeat treatment cycle once. For detailed information on correct application, see the product information fluorouracil fluorouracil fluorouracil
OR
1imiquimod 5% cream topically, at night 5 times a week (on consecutive nights) for up to 6 weeks. For detailed information on correct application, see the product information. imiquimod imiquimod imiquimod
Photodynamic therapy can be considered by specialists as an alternative to fluorouracil and imiquimod topical field treatments. Photodynamic therapy involves application of a photosensitiser to the affected skin, followed by activation with light. Various photosensitisers and light delivery techniques are available. Good technique and patient selection are important for optimal response.
SCC in situ that has deep extension down hair follicles, and hypertrophic or hyperkeratotic lesions, are unlikely to successfully clear with topical therapy, and may require surgical excision.
For a lesion that fails to respond to topical therapy, or that recurs after treatment, biopsy is recommended to clarify the diagnosis. Surgical excision is recommended.
Mohs micrographic surgery can be used for lesions where tissue conservation is important (eg face, fingers, toes, genitals). Radiotherapy is an option in select cases where surgery is complicated or contraindicated.
After treatment of SCC in situ, follow-up is recommended to review response to treatment, monitor for recurrence and for ongoing surveillance of new primary skin cancers. The recommended frequency of follow-up (eg every 6 to 12 months) depends on patient risk factors (eg immunosuppression, degree of sun damage).