When we think about chemotherapy, many of us think of intravenous medications for the treatment of cancer that result in difficult side effects such as hair loss and nausea. While these medications can be highly effective, they’re also hard on the body.
Much like our preconceived chemotherapy associations, topical chemotherapy targets and destroys cancer or precancerous cells, but it doesn’t lead to hair loss or sickness in the same way. While powerful, topical chemotherapy is an at-home, nonsurgical solution to ridding your body of unhealthy cells.
Topical chemotherapy, also known as field therapy, is the use of a topical product to treat cancerous or precancerous skin lesions on a specific place or a specific geographic area of the skin (like the face, scalp, or hands). These creams or solutions are applied directly to the skin as directed by a doctor.
Common Uses of Topical Chemotherapy
Field therapy is most commonly used to treat sun-exposed areas with many precancerous lesions. The easiest way to treat a precancerous lesion is to freeze it during your full skin exam.
However, if you have 25+ lesions on your face and scalp, freezing isn’t the most thorough approach. With topical chemotherapy, you’ll apply the medication over the entire area. Consequently, you’ll treat the visible problematic cells as well as the cells that haven’t yet turned red or scaly. These medications only affect precancerous cells. They target unhealthy cells and leave healthy cells alone.
We also use topical chemotherapy as a nonsurgical alternative to treating specific types of skin cancer. Superficial basal cell carcinoma responds well to topical chemotherapy. We can also use it as an early squamous cell carcinoma treatment. In rare cases, it targets a specific early form of melanoma.
Why Would My Dermatologist Not Use Topical Chemotherapy?
While topical chemotherapy provides an effective precancerous lesion, basal cell carcinoma, and squamous cell carcinoma treatment for many patients, it’s not the best option in every scenario. In order to determine if topical chemotherapy is the best option, we have to consider the location of the lesion, the type of cancer, and the patient’s immune health.
Sensitive areas, such as the eyelid, are not candidates for topical chemotherapy. Other areas on the face, hands, and scalp allow for the application of this medication without further damage to the tissue.
Type of Cancer
Topical therapy is not appropriate for every type of skin cancer. While it’s an effective form of superficial basal cell and squamous cell carcinoma treatment, it’s not a solution to invasive squamous cell carcinoma, invasive melanoma, and certain types of basal cells.
Patient Immune Health
Topical field therapy relies on a healthy immune system to be effective. Skin cancer, however, is common in people who are immunocompromised. Without a functioning immune system, some of these medicines will not work and will not be offered as a treatment option. Surgical treatment is usually more appropriate for the immunocompromised patient.
Side Effects of Topical Chemotherapy
While field therapy is often the best treatment option, it’s accompanied by some uncomfortable side effects. Expect inflammation when using topical chemotherapy. The medicine works because it’s absorbed by the bad cells (precancerous or cancerous). As those cells die, they turn red, scab, and swell.
Depending on which topical product you’re using, it may take a few days for the inflammation to start. Once it does, the inflammation will progressively intensify over the course of treatment resulting in increased redness and scabbing.
This is not the treatment you start before family photos, headshots, or a beach vacation. Your skin will temporarily look worse before it gets better. If you’re worried about the amount of inflammation during your treatment, come in for a check-up so we can evaluate and assure you if your reaction is normal.
Also, limit treatments to one large surface area at a time. If multiple areas need treatment, we advise patients to separate their course treatment into multiple sessions. For example, a patient can treat their head (face, neck, and scalp) in one course of treatment. Then, at a later date, they would treat their arms. They would not treat the head and arms at the same time.
If too many surface areas are treated at once, you run the risk of systemic absorption of the medication, resulting in flu-like sickness.
What Medications are Considered Topical Chemotherapy?
There are five primary medications used for topical chemotherapy available in either creams or solutions:
- Fluorouracil (known as 5-FU, Effudex, Carac) comes in a 5% cream and is often used to treat actinic keratosis and superficial basal cell carcinoma. We recommend using this 1-2 times per day for 1-4 weeks. While patients appreciate a short course of treatment, the inflammation is intense during this period.
- Imiquimod (branded as Aldara) also treats actinic keratosis and superficial basal cell carcinoma. For actinic keratosis, application is 2 times/ week for a few months which results in less inflammation than 5-FU, but the course of treatment is significantly longer. This medication can also be used off-label for nodular basal cell carcinoma and certain types of melanoma where surgery isn’t an option.
- Solaraze gel is a topical version of diclofenac (similar to ibuprofen or non-steroidal anti-inflammatory medications). This is the least inflammatory option, but it requires a twice per day application over at least three months. Some prefer this medication because it results in a slower burn with less inflammation, pain, redness, and scabbing, but it’s a longer commitment to treatment.
- Ingenol mebutate (branded as Picato) offers a short treatment course. Lesions on the face and scalp only need a three-day treatment. Lesions on the body tolerate a higher concentration of the medication and only need a two-day treatment. Because the treatment is so compressed, it’s extremely inflammatory.
- Photodynamic therapy (PDT) isn’t a cream or a solution, but an in-office treatment. PDT is used along with aminolevulinic acid. The patient comes to the office, the doctor applies the medication, and the patient waits in the office for 2-3 hours. They cannot be in the sunlight during this time. The patient then sits in front of a blue light that specifically activates the medication for 17 minutes.
Before any topical chemotherapy, we ask patients if they have a history of oral herpes or cold sores. If so, there’s a risk that these medications or light therapy can trigger an outbreak. We prevent this by giving them medication to proactively prevent an outbreak.
During (and after) any of these treatments, limit sun exposure. During time outside, wear a wide-brim hat and apply sunscreen. Your skin is inflamed because you’re undergoing treatment. Sun exposure will increase this inflammation.
How Often Will I Need Topical Chemotherapy?
For some patients, one round of topical chemotherapy is all that’s necessary to treat their current skin lesions. However, topical chemotherapy is also a preventative measure against future skin cancer. Many patients use topical chemotherapy quarterly to actively combat skin cancer. Each treatment cleans up a significant amount of damaged tissue. Consequently, we find that patients experience less inflammation and side effects with each subsequent treatment as there are less damaged cells present.
How To Know If Topical Chemotherapy Is Right For You
If you’re looking to treat damaged skin cells and your doctor recommends field therapy or topical chemotherapy, make an informed decision. Talk to your dermatologist about the medication they’d recommend, how many rounds they suspect you’ll need, and how many areas need to be treated. For many patients, topical chemotherapy is the perfect treatment for both their lifestyle and the health of their skin.
Dr. Winslow Blankenship is a board-certified dermatologist in Breckenridge and Vail, CO. She is an expert in medical dermatology and finds great reward in the management of acne, psoriasis, and other dermatologic conditions. She particularly enjoys that dermatology allows her to care for both adult and pediatric patients, having completed a significant portion of her residency training at Children’s National Medical Center in Washington, DC. In her spare time, Dr. Blankenship enjoys skiing with her husband and children.