Effects of Creams Applied for Radiotherapy Burns on Skin Adverse Effects

Known to patients as radiotherapy burns , radiation dermatitisis a common adverse effect of radiation treatment and is often treated with topical creams (applied to the skin). However, patients are frequently advised to avoid creams for several hours before radiotherapy because of concern that they may increase the radiation dose to the skin and thus adverse effects. Yet particularly for targeted modern radiotherapy , whether this precaution is necessary is debated. To assess whether applying metallic or nonmetallic creams before radiation treatment alters the radiotherapy skin dose, a study's results were published on 18 October 2018 in JAMA Oncology.

Baumann and colleagues measured both the prevalence of this belief and whether creams truly have such an effect. Among surveyed doctors, % 91 recommended that creams not be applied before treatment to reduce radiotherapy's skin adverse effects, and % 83 of patients reported receiving such advice from their doctors. However, preclinical testing showed that applying or not applying cream did not change the radiotherapy skin dose.

Radiation treatment will cause radiation dermatitis, appearing as redness or burns, in many patients. Both prescription and over-the-counter creams are widely used to provide relief; some, such as silver sulfadiazine cream, contain heavy metals. However, patients may often be advised not to use these treatments in the hours before radiation therapy to prevent an increase in radiation absorbed by the skin.

"Although this advice seemed reasonable in the first half of the 20th century, when radiotherapy began to be used for cancer, they hypothesized that it might no longer be appropriate with modern radiation treatments that can reduce the dose delivered to the skin" say the study authors.

Survey Stage

For the first part of the research, investigators used an online cancer service developed for patient and caregiver education, OncoLink.

Among 105 doctors and nurses frequently encountering patients with radiation dermatitis, 96 (% 91) did not recommend skin creams in the hours before radiotherapy. On the patient side, among 133 participants, 111 (% 83) reported receiving this advice from oncology specialists.

Testing Radiation Doses Delivered to the Skin

To address whether these topical agents (creams) actually increase skin radiation dose, researchers used optically stimulated luminescent dosimeters. These devices can measure the amount of surface radiation absorbed by the skin.

Dosimetric measurements showed that, even at different radiotherapy doses, cream layers up to 2 millimeters thick made no difference in skin dose. However, layers of 3 millimeters or more increased the skin radiotherapy dose.

Conclusion

Based on these results, use of creams immediately before radiation treatment can safely be allowed, potentially improving quality of life for patients undergoing radiation therapy, but thick cream applications immediately before treatment should be avoided. In conclusion, a thin layer of cream can be applied before radiotherapy, or, as in older recommendations, application can wait until 2 hours after radiotherapy.