BackgroundAn increased prevalence of allergies and an increased incidence of breast cancer have been observed. The hypothesis that atopy may have a protective effect against the risk of different types of breast cancer was evaluated. MethodsIn this study, 11,101 patients (11,101 women with a mean age of 55.2±14.7 years) with different types of breast cancer were tested for allergies. Allergies were confirmed based on the retrospective analysis of allergy diagnostic procedures in patients who had been previously diagnosed with breast cancer. The retrospective prevalence rates of active allergic diseases, including allergic rhinitis, bronchial asthma and atopic dermatitis, were assessed. All patients were also analyzed for bronchial asthma and allergic rhinitis according to the relevant guidelines. A group of healthy control patients was used for the comparisons. ResultsThe women with breast cancer had a significantly lower incidence of IgE-mediated allergic diseases than the controls. The odds ratios (ORs) for allergic rhinitis, atopic dermatitis, and bronchial asthma were 0.61 (95% CI: 0.57-0.73), 0.17 (95% CI: 0.11-0.44), and 0.73 (95% CI: 0.65-0.83), respectively. The mean serum concentrations of total IgE were significantly lower in the study population of women with breast cancer than in the patients of the control group (39.2 ± 26.2 kU/L vs. 108.5 ± 38.5 kU/L; p = 0.002). ConclusionOur results suggest that the overall incidence of allergies, especially allergic rhinitis, is lower in patients with certain types of cancer than in individuals who did not have cancer. Further studies are needed to confirm our findings.

Introduction: Allergen immunotherapy (AIT) is very important and effective and reduces medication use in patients with allergic rhinitis. However, some patients have no response to AIT. Aim: To explore the problem of nonresponding patients after AIT. Material and methods: This retrospective randomized observational study included 1056 patients with allergic rhinitis who underwent subcutaneous injection allergen immunotherapy (SCIT). Patients who received SCIT to one of the following allergens: grass pollen, birch, trees, mugwort, house dust mites, Alternaria or cat were analyzed according to the inclusion criterion of ≥ 20% improvement in all monitored parameters. There were symptoms and medication score, rhinitis symptom score and serum allergen-specific IgE and IgG4. Results: A total of 806 (76.3%) patients met the criterion of 20% or greater improvement after SCIT. The greatest effectiveness was obtained in patients receiving SCIT to grass pollen (293 participants; 83.2%), birch (82; 81.2%) and house dust mites (255; 76.4%). Statistically significant predictors of an improved AIT outcome in the multivariate analysis were SCIT to grass pollen (OR = 2.34, p = 0.035), SCIT to birch (OR = 2.25, p = 0.021) and the presence of only intermittent allergic rhinitis before SCIT (OR = 2.05, p = 0.039). Patients who received SCIT to mugwort, Alternaria or cat had weak response results especially in long-term observations. Conclusions: The best predictors to obtain good responsiveness to SCIT are the presence of intermittent allergic rhinitis to grass or birch pollen. Patients with allergies to mugwort, Alternaria and cat with a prolonged duration of persistent allergic rhinitis dominated in the group of nonresponders to SCIT.