RESUMO
PURPOSE: Oral hygiene is crucial in the management of oral and febrile complications during chemotherapy for cancer. This study aimed to investigate the impact of oral hygiene on the incidence of febrile neutropenia (FN) throughout the course of chemotherapy for breast cancer. METHODS: A total of 137 patients with breast cancer who underwent four cycles of adjuvant chemotherapy with docetaxel and cyclophosphamide (TC) combination therapy or docetaxel alone were assessed for oral hygiene by quantifying the number of oral bacteria they harbored. These patients received professional oral health care (POHC). Eighteen patients underwent primary prophylaxis with granulocyte colony-stimulating factors. The relationship between oral bacteria count and FN incidence was retrospectively assessed. RESULTS: The FN incidence rate was 47.4% throughout all treatment cycles (32.8%, 13.5%, 14.3%, and 14.4% in cycles 1, 2, 3, and 4, respectively). The oral bacteria count decreased with each treatment cycle (cycle 1: 9.10 × 106 colony-forming units (CFU)/mL, cycle 2: 5.89 × 106 CFU/mL, cycle 3: 4.61 × 106 CFU/mL, cycle 4: 5.85 × 106 CFU/mL, P = 0.004). Among 281 treatment cycles, FN occurred in 63 (22.4%). In the treatment cycle-based analysis, high oral bacteria count was an independent risk factor for FN. CONCLUSION: FN incidence decreased with each treatment cycle and was associated with changes in oral bacteria counts. The oral bacterial count was one of risk factors for FN development in breast cancer.