title: Neurological complications of breast cancer: A prospective cohort study.
abstract: OBJECTIVE
  Neurological complications secondary to breast cancer treatment may be an important contributor to these patients morbidity. We aimed to quantify the incidence of neurological complications of breast cancer treatment during the first year after diagnosis.
  
  
  METHODS
  We performed a prospective cohort study with 506 patients recruited at the Portuguese Institute of Oncology of Porto, among those newly diagnosed. Participants underwent a neurological examination before treatment, after surgery, after chemotherapy (whenever applicable) and at one year after enrollment. The Montreal Cognitive Assessment was used to assess cognitive function, at baseline and at one year. We computed one-year cumulative incidence estimates and the corresponding 95% confidence intervals (95%CI) for each of the neurological complications.
  
  
  RESULTS
  Just over half of women had breast cancer stage 0 or I. A total of 6.9% were submitted to neoadjuvant chemotherapy but most of them completed adjuvant treatment - endocrine therapy, radiotherapy or chemotherapy (83.9%, 73.0% and 52.5%, respectively). The cumulative incidence of at least one oncological-related neurological complication during the first year after diagnosis was 48.4% (95%CI: 44.1-52.8); the most frequent were neuropathic pain (30.8%, 95%CI: 27.0-35.0), chemotherapy-induced peripheral neuropathy (16.8%, 95%CI: 13.8-20.3), phantom breast pain/syndrome (16.6%, 95%CI: 13.6-20.1) and cognitive decline (8.1%, 95%CI: 5.8-11.1).
  
  
  CONCLUSIONS
  Neurological complications were a frequent side-effect of breast cancer management in the first year after diagnosis, especially neuropathic pain and chemotherapy-induced peripheral neuropathy. Accurate diagnosis and treatment of these complications are important to minimize the burden associated with breast cancer treatment in breast cancer survivors.
authors.affiliation: Portuguese Institute of Oncology of Porto, Rua Dr. António Bernardino de Almeida, 4200-072 Porto, Portugal; EPIUnit - Institute of Public Health, University of Porto (ISPUP), Rua das Taipas, nº135, 4050-600 Porto, Portugal.
authors.forename: Susana
authors.initials: S
authors.lastname: Pereira
authors.affiliation: EPIUnit - Institute of Public Health, University of Porto (ISPUP), Rua das Taipas, nº135, 4050-600 Porto, Portugal; Department of Clinical Epidemiology, Predictive Medicine and Public Health, Faculty of Medicine, University of Porto, Al. Prof. Hernâni Monteiro, 4200-319 Porto, Portugal.
authors.forename: Filipa
authors.initials: F
authors.lastname: Fontes
authors.affiliation: Portuguese Institute of Oncology of Porto, Rua Dr. António Bernardino de Almeida, 4200-072 Porto, Portugal.
authors.forename: Teresa
authors.initials: T
authors.lastname: Sonin
authors.affiliation: Portuguese Institute of Oncology of Porto, Rua Dr. António Bernardino de Almeida, 4200-072 Porto, Portugal.
authors.forename: Teresa
authors.initials: T
authors.lastname: Dias
authors.affiliation: Portuguese Institute of Oncology of Porto, Rua Dr. António Bernardino de Almeida, 4200-072 Porto, Portugal.
authors.forename: Maria
authors.initials: M
authors.lastname: Fragoso
authors.affiliation: Department of Experimental Biology, Faculty of Medicine, University of Porto, Al. Prof. Hernâni Monteiro, 4200-319 Porto, Portugal; Institute for Molecular and Cell Biology (IBMC), University of Porto, Rua do Campo Alegre, nº 823, 4150-180 Porto, Portugal.
authors.forename: José Manuel
authors.initials: JM
authors.lastname: Castro-Lopes
authors.affiliation: EPIUnit - Institute of Public Health, University of Porto (ISPUP), Rua das Taipas, nº135, 4050-600 Porto, Portugal; Department of Clinical Epidemiology, Predictive Medicine and Public Health, Faculty of Medicine, University of Porto, Al. Prof. Hernâni Monteiro, 4200-319 Porto, Portugal. Electronic address: nlunet@med.up.pt.
authors.forename: Nuno
authors.initials: N
authors.lastname: Lunet
mesh_terms: D000970:Antineoplastic Agents / Q000009:adverse effects; D001943:Breast Neoplasms / Q000150:complications / Q000628:therapy*; D017024:Chemotherapy, Adjuvant / Q000009:adverse effects; D003072:Cognition Disorders / Q000453:epidemiology* / Q000209:etiology; D005260:Female; D006801:Humans; D015994:Incidence; D008197:Lymph Node Excision / Q000009:adverse effects*; D008408:Mastectomy / Q000009:adverse effects; D008875:Middle Aged; D020360:Neoadjuvant Therapy / Q000009:adverse effects; D009437:Neuralgia / Q000453:epidemiology* / Q000209:etiology; D011174:Portugal / Q000453:epidemiology; D011446:Prospective Studies; D018714:Radiotherapy, Adjuvant / Q000009:adverse effects; D012678:Sensation Disorders / Q000139:chemically induced / Q000453:epidemiology
chemical_list: D000970:Antineoplastic Agents
keywords: Breast Neoplasm; Nervous system diseases; Neuropathic pain; Polyneuropathies