Patient-reported Outcomes of Adverse Events After Perioperative Chemotherapy for Breast Cancer: A Prospective Observational Study

Background/Aim: structured questionnaires allow for more accurate assessment of the patients' symptoms. This prospective observational study used a PRO-based questionnaire to assess the long-term course of AEs among patients with breast cancer who underwent perioperative chemotherapy. Patients and Methods: Patients with operable breast cancer who received perioperative chemotherapy with a docetaxel/cyclophosphamide (TC) or anthracycline- and taxane-based chemotherapy regimen (A+T) were enrolled. A PRO-based questionnaire, prepared for this study and aligned with the Common Terminology Criteria for Adverse Events, was administered at the end of each patient's chemotherapy regimen and 6 months later. The questionnaire covered nausea, vomiting, oral mucositis, constipation, diarrhea, dysgeusia, insomnia, neuropathy, nail loss, and alopecia. The frequency and severity of each AE were compared between regimens, and longitudinal changes were analyzed. Results: A total of 115 patients (median age 50 years) were evaluated. Nausea, vomiting, mucositis, constipation, dysgeusia, insomnia, peripheral neuropathy, and nail loss were common at the end of the patients' chemotherapy regimens, but 6 months later the frequency of gastrointestinal symptoms had decreased. Several AEs persisted beyond 6 months; notably, neuropathy, dysgeusia, insomnia, and nail loss. Grade 3 symptoms persisted for neuropathy, and nail loss was confirmed to have increased at 6 months. Compared to the TC chemotherapy, peripheral sensory neuropathy persisted longer in the A+T group. Conclusion: PROs are thought to capture persistent symptoms that are often underestimated in conventional clinical practice. In the present breast cancer series, PRO-based monitoring revealed regimen-specific AE profiles and the persistence of neuropathy, dysgeusia, and nail changes beyond chemotherapy. These findings highlight the importance of monitoring not only during chemotherapy, but also in the months after the chemotherapy's completion, when patients continue to suffer from persistent symptoms. Incorporating structured PRO-based questionnaires into follow-up care may be crucial for optimizing supportive management.