Table 4.
Risk factors and radiation recall dermatitis (RRD) univariate analysis.
| Risk factors | N° events/n° exposed | % | P value |
|---|---|---|---|
| Timing end EBRT-vaccination | |||
| 15–30 days | 4/32 (doses) | 12.5 | 0.0004 |
| >30 days | 16/724 | 2.2 | |
| Vaccination n° after EBRT | |||
| First vaccination after EBRT | 16/361 (doses) | 4.4 | 0.003 |
| Second/third vaccination after EBRT | 4/395 | 1 | |
| Vaccination drug | |||
| Comirnaty (Pfizer/Biontech) | 14/529 (doses) | 2.4 | NS |
| Spikevax (Moderna) | 6/194 | 3.1 | |
| Vaxzevria (Astrazeneca) | 0/28 | 0 | |
| Janssen COVID-19 vaccine | 0/5 | 0 | |
| EBRT schedule | |||
| 50Gy/25fr. or 40.05Gy/15fr. | 16/264 (patients) | 6.1 | NS |
| 26Gy/5fr | 4/97 | 4.1 | |
| Tumor bed boost | |||
| Yes | 10/208 (patients) | 4.8 | NS |
| No | 10/153 | 6.5 | |
| Anthracycline-based chemotherapy | |||
| Yes | 5/109 (patients) | 4.6 | NS |
| No | 15/252 | 6 | |
| Taxane-based chemotherapy | |||
| Yes | 3/119 (patients) | 2.5 | NS |
| No | 17/242 | 7 | |
| Anti-HER2 drugs | |||
| Yes | 1/33 (patients) | 3 | NS |
| No | 19/328 | 5.8 | |
| Endocrine therapy | |||
| Yes | 16/260 (patients) | 6.1 | NS |
| No | 4/101 | 4 | |
| Age at EBRT beginning | |||
| ≥70 years | 3/62 (patients) | 4.8 | NS |
| <70 years | 17/202 | 8.4 | |
| Delayed breast reconstruction | |||
| Yes | 1/17 (patients) | 5.9 | NS |
| No | 19/344 | 5.5 | |
| COVID-19 infection | |||
| Yes | 2/61 (patients) | 3.3 | NS |
| No | 18/300 | 6 | |
| Corticosteroid intake concomitant vaccination | |||
| Yes | 1/14 (patients) | 7.1 | NS |
| No | 19/347 | 5.5 | |
Univariate analysis for potential risk factors was calculated by chi square-test or fisher-exact test as appropriate. P-value < 0.05 was considered statistically significant.
NS = not significant.