Dermal recall effect in breast radiotherapy patients after vaccine administration

ABSTRACT

Purpose or Objective The dermal recall phenomenon is an increase in the sensitivity of stem cells in the area of the treatment field and may lead to increased acute toxicity. Afterwards, the recall effect has been described in those patients who have been vaccinated against COVID during radiotherapy treatment. Our objective has been to observe if we are facing a dermal recall phenomenon after the administration of the vaccine in patients who are on the course of radiotherapy. Materials and Methods Coinciding with the vaccination campaign against SARS-CoV-2 in oncological patients, which began in our environment in March 2021, we have collected data on radiodermatitis that have been presented by 42 patients after the end of radiation therapy treatment for breast cancer Results The percentage of patients vaccinated were as follows 57% (24/ 42 patients) Of which 6/24 patients received the vaccine dose during radiation therapy Of the 42 patients treated with radiation therapy, 3 had a degree 3 dermal toxicity. These 3 patients were given the vaccine during radiotherapy treatment, which accounts for 50% of the patients vaccinated during radiotherapy. Note that of the 845 patients treated with hypofractionation radiotherapy since 2016 only 0.23% have presented grade 3 acute radiodermatitis, versus 7% of the patients who have been vaccinated during radiotherapy Conclusion We estimate that most likely, the vaccine carries a greater risk of skin toxicity mediated by the dermal recall phenomenon but that does not mean that the administration of the vaccine should be contraindicated, but more closely warn patients who receive the vaccine during radiation therapy.