The study team was not able to start the study and they never completed the IRB submission, so the study was terminated.

The aim of this study is to determine the effectiveness of combination calcipotriene 0.005% foam and 5% fluorouracil cream for the treatment of actinic keratoses on the scalp. The data obtained will be compared with the current standard of care, monotherapy with 5% fluorouracil cream. A recent randomized, double-blind clinical trial (NCT02019355) compared 0.005% calcipotriol ointment and fluorouracil 5% cream with Vaseline plus fluorouracil 5% cream for a 4-day treatment of actinic keratoses on the face, scalp and upper extremities. They found that calcipotriol plus 5-FU versus Vaseline plus fluorouracil 5% cream led to an 87.8% versus 26.3% mean reduction in the mean number of actinic keratoses. Our study will independently assess the effectiveness of combination treatment (calcipotriene 0.005% foam and fluorouracil 5% cream) on scalp actinic keratoses in a case series of up to 15 eligible participants. Participants will complete a 4-night application of combination treatment with follow-up immediately after and 8 weeks later.

Inclusion Criteria:

• Age of at least 40 years.
• Presence of four to fifteen clinically typical, visible, and discrete actinic keratoses in 25 cm2 on the scalp.
• Ability and willingness of the patient to participate in the study (Informed consent is obtained)

Exclusion Criteria:

• Treatment area is within 5 cm of an incompletely healed wound or a suspected basal-cell or squamous-cell carcinoma
• Treatment area contains hypertrophic/hyperkeratotic lesions, cutaneous horns, or lesions that had not responded to repeated cryotherapy
• Recent (within a month) use of medications that could interfere with evaluation of the treatment area (e.g., topical medications, artificial tanners, immunosuppressive medications, immunomodulating agents, cytotoxic drugs, ultraviolet B phototherapy, other therapies for actinic keratoses, or oral retinoids)
• Premenopausal Women (to avoid any risk of pregnancy)
• History of hypercalcemia or clinical evidence of vitamin D toxicity (avoidance of calcipotriene toxicity).