Trial results investigating patient experiences with COVID-19 vaccination after breast cancer treatment were posted on ClinicalTrials.gov on 2026-01-06, involving 714 participants.
Background
COVID-19 vaccination has been a critical public health measure. However, a known side effect of mRNA vaccines (Moderna and Pfizer) is lymph node swelling, which is a normal immune response. For patients who have undergone breast cancer treatment, particularly those with lymph node removal (axillary lymph node dissection or sentinel lymph node biopsy), this swelling can be a source of significant worry and anxiety, as it can mimic the appearance of breast cancer recurrence or spread to the lymph nodes. Understanding patient experiences and the incidence of this side effect is important for patient counseling and care.
Trial design
This completed study enrolled 714 participants to investigate patient experiences with COVID-19 vaccination after breast cancer treatment. The study focused on individuals with conditions including Breast Cancer Related Lymphedema and Covid19. The primary aim was to elicit patient experiences, choices, and side effects associated with the COVID-19 vaccine following breast cancer surgery, specifically noting the concern regarding lymph node swelling.
Key results
The study reported several key measurements related to COVID-19 vaccination experiences and lymph node swelling:
- COVID-19 Vaccination on Contralateral vs Ipsilateral Arm:
- For vaccinated breast cancer patients receiving mRNA vaccines (Moderna, Pfizer), 432 participants received Dose 1.
- 435 participants received Dose 2.
- 331 participants received a Booster dose.
- In another group of vaccinated breast cancer patients receiving mRNA vaccines, 122 participants received Dose 1.
- 119 participants received Dose 2.
- 74 participants received a Booster dose.
- Lymph Node (LN) Swelling After COVID-19 Vaccine:
- Among vaccinated breast cancer patients receiving mRNA vaccines (Moderna, Pfizer), 61 participants reported lymph node swelling after Dose 1.
- 80 participants reported lymph node swelling after Dose 2.
- 53 participants reported lymph node swelling after a Booster dose.
- For vaccinated breast cancer patients receiving non-mRNA vaccines (Johnson & Johnson), 4 participants reported lymph node swelling after Dose 1.
- 1 participant reported lymph node swelling after a Booster dose.
- Additionally, 11 participants in a group receiving mRNA vaccines (Moderna, Pfizer) reported lymph node swelling after Dose 1.
What this means
The posted results provide specific counts regarding patient experiences with COVID-19 vaccination after breast cancer treatment, particularly focusing on the occurrence of lymph node swelling. The data highlights that lymph node swelling is reported by a notable number of breast cancer patients after both mRNA and non-mRNA COVID-19 vaccinations, across different doses. This information is valuable for clinicians in counseling breast cancer patients about potential vaccine side effects, helping to differentiate normal immune responses from concerns about cancer recurrence, thereby potentially reducing patient anxiety.
Source
The information regarding these trial results was obtained from ClinicalTrials.gov, a public database of clinical studies. The results for the study NCT04872738, titled "Patient Experiences With the COVID-19 Vaccination After Breast Cancer Treatment", were posted on 2026-01-06 on clinicaltrials.gov.