A Dermatologist Answers Questions about Topical Chemotherapy Creams
One of the frequent questions we get here on SkinCancerConnection is about the use of topical medications used to treat pre-cancerous growths such as actinic keratoses which can be a precursor to developing squamous cell skin cancer. Three of the most commonly used medications to treat such lesions include Efudex, Aldara and Carac. We have asked Doctor Lawrence Green, a practicing dermatologist and Assistant Clinical Professor of Dermatology at George Washington University School of Medicine in Washington DC to answer some questions about these topical chemo creams and how they work.
Welcome Doctor Green. We are glad you could join us here SkinCancerConnection.
Three of the most commonly asked about topical chemo creams include: Efudex, Carac, and Aldara. Are there any other topical medications commonly prescribed for treating precancerous skin lesions?
Zyclara is a new topical cream that is FDA approved to treat precancerous skin growths. It is a less potent version of Aldara, and is meant to use as "field therapy", meaning all over 1 area (like the face or arms) instead of just spot treating like Aldara is used. What conditions can be treated with such topical creams? Topical creams are FDA approved for treating precancerous skin growths called actinic keratoses. Aldara is also FDA approved for treatment of superficial basal cell carcinomas- a less common form of basal cell carcinoma-on the trunk. Some people feel Efudex can also treat superficial basal cell carcinomas on the trunk and there are some small case studies that show this. In my experience, these medications are best used for treating just precancerous actinic keratoses, and not basal cell carcinomas.
Some members question whether freezing is more effective in treating precancerous lesions such as actinic keratoses. What factors go into choosing one treatment over another?
In my opinion, freezing is preferred if the person has just a few precancerous lesions to treat. If they have many, freezing is too cumbersome and a cream is a better choice. On the other hand, to treat just 1 or 2 spots with a cream daily for a few weeks is a lot of trouble when you can just freeze those few spots in the office quickly. I also think freezing gives better results if you are treating just a few lesions, because the dermatologist can focus on just those and be thorough. If there are many spots to treat, it is more difficult to get them all accurately.
What are the possible dangers or side effects of using such topical medications on the skin?** Are there any patients who should not be using these medications?**
No real dangers, but skin that is precancerous can become very scabbed, red and irritated. But that is what you want and is a desired result. That said, I would not recommend using Carac or Efudex on children or pregnant/nursing women. For Aldara and Zyclara (which are also used in an off label manner to treat warts in children) there are occasional instances of flu like symptoms following their use, especially if the person doesn't wash the area where they applied the cream on the morning following their bedtime application (approximately 8 hours later).
If the medication gets on "normal" skin, what happens?
All of these medications cause the skin to become very scabbed on precancerous skin. They do not affect skin that is normal even if you put it on normal skin. So, that is a good thing. The one exception is intertriginous skin like the penis, groin, vaginal area, axillas, etc. These creams can cause a very irritating rash if it gets there. So, the best idea is to wash your hands well after you apply any of these creams so you don't accidentally touch a sensitive area after you have applied them.
Is there any part of the body where these creams should not be used? Some people ask about the skin around the eyes.
See above, but I would also be careful on skin in the corners of the eyes and around the eyelids.
What is the general time line for healing from such medications? What can the patient reasonably expect?
Healing should occur about 2-3 weeks once you stop using these medications. You should expect all the precancerous areas of your skin (which is usually much more than you realize) where you apply the cream to become red, inflamed and scabbed until a few weeks after you stop using it. But people almost always heal very well and actually their skin looks quite refreshed after it has healed.
Should a patient become concerned when they see redness, scaling, or scabs? Any dangers in picking off the scab?
Redness, scaling, and scabs are expected, but please don't pick at them. Picking can cause these areas to become infected. If the scabbed areas bother you, apply a topical antibiotic ointment like Bacitracin or Aquaphor. Sometimes, your dermatologist will prescribe topical cortisone creams to help the redness.
Many members ask about what they can safely use after they are done using the topical chemo creams such as make up, soaps, and general skin care products. They also want to know what products might speed up the healing process.
I think gentle cleansers, soaps, and lotions are all OK to use. Aquaphor is a great idea to help speed up the healing or just help things heal well.
Thank you Doctor Green, for sharing your expertise with us today. For even more information about topical medications to treat early forms of skin cancer please read Doctor Kevin Berman's article entitled, Efudex, Aldara, and Other Skin Cancer Topical Creams.