5-Fluorouracil and Calcipotriene for Treatment of Low Grade Skin Cancer

The investigators will compare the application of two different creams for the treatment of low-risk skin cancers-superficial basal cell carcinoma (sBCC) and squamous cell carcinoma in situ (SCCis). 5-Fluorouracil cream is currently FDA approved for the treatment of superficial basal cell carcinoma and is routinely used by dermatologists across the country and at Boston Medical Center (BMC) for SCCis. The normal treatment regimen is 4 weeks of the 5-fluorouracil cream for both skin cancers.

The application of a compounded cream consisting of 1:1 ratio 5-fluorouracil with calcipotriene will be tested. This combination cream has been shown to clear pre-skin cancers called actinic keratoses and prevent future skin cancers from developing. This combination cream for 7-14 days to see if this shorter treatment course provides clearance of the 2 types of skin cancer. This combination cream is successfully used in this manner to treat other subtypes of related skin cancers. This will be a pilot study with

The primary endpoint for this pilot randomized single blinded clinical trial will be the response to treatment (yes versus no). The lesions will be assessed clinically for clearance of cancer, as would normally be done and is consistent with how comparable studies have assessed clearance. Participants will be followed closely afterwards for three years with visits at 6 months, which does not vary from standard practice. If the lesions are not clear of cancer or equivocal clinically, the lesions will be re-biopsied and normal standard of care procedure will take place.


Eligibility Criteria:
Inclusion Criteria:

* English-speaking
* Having a previously untreated, biopsy-proven Superficial Basal Cell Carcinoma (sBCC) or Squamous Cell Carcinoma in Situ (SCCis) of the skin \<2 cm on the scalp, trunk, neck, or extremities, excluding hands, feet, and genitalia
* Having a previously untreated, biopsy-proven sBCC or SCCis on the face, hands, feet, and genitalia who decline surgery or are otherwise not surgical candidates
* Willing to undergo all protocol requirements and attend study-specific follow up clinic visits in addition to routine follow up visits
* Participants may have multiple lesions enrolled in the study so long as the individual lesions are greater than 2 cm from each other
* If a woman is of childbearing potential, the participant must be willing to take a pregnancy test before starting treatment and be on some form of birth control while receiving treatment. Birth control can include abstinence, oral contraceptive pill, intrauterine device, implanted birth control device, birth control patch, or the vaginal ring. The patient does not need to be on any form of birth control after they end therapy.

Exclusion Criteria:

* Current or prior field treatment within 2 cm of the target BCC or SCCis
* Periorbital lesions
* Lesions that have been previously treated
* Known allergy to any of the study medication ingredients
* History of solid organ transplant or current immunosuppression
* Genetic disorders associated with high skin cancer risk
* Arsenic exposure
* Cutaneous T-cell lymphoma
* Current or prior radiation therapy at the site of the sBCC or SCCis
* Women who are pregnant or currently breastfeeding
* Prior psoralen plus Ultraviolet light (UVA) treatment at the site
* Very high mortality risk at the start of the study
* Dihydropyrimidine dehydrogenase (DPD) enzyme deficiency
* Demonstrated hypercalcemia or evidence of vitamin D toxicity
* Lesions that extend into the oral, nasal or genital mucosa