Indicações de imunohistoquímica em patologia cirúrgica em um hospital público de referência em oncologia na cidade de Manaus

Abstract

Background: Immunohistochemistry (IHC) is considered the gold standard for distinguishing tumor lineage and for differential diagnosis in hematoxylin and eosin-stained slides that did not provide conclusive information. Currently, the lack of a pathology service with the capacity to perform immunohistochemical tests through the Unified Health System in the state of Amazonas presents obstacles such as the need to send samples to other states, which can delay the start of cancer treatment. Outsourcing a large volume of immunohistochemical tests can result in the loss of information relevant to the case (such as age, sex, age, topography, time of evolution), the appropriate indication for the IHC test (such as diagnostic confirmation, prognostic factors, response to targeted therapies), and make it difficult to delineate the epidemiological profile of patients. Objectives: To describe the main indications for IHC in a Pathology service of a public referral hospital in oncology in the city of Manaus, from 2016 to 2020. To characterize the profile of patients whose IHC exams were requested, according to sex, age, and topography. To describe the indications for IHC by topography, the main diagnoses, the number of antibodies, and the time elapsed between the initial and final diagnoses. Methods: This was a retrospective, descriptive, non-interventional study to analyze the indication for immunohistochemical exams of patients treated at the Fundação Centro de Controle de Oncologia do Amazonas (FCECON), from 2016 to 2020. Results: The analysis of the indication profile of 3,299 IHC exams of patients treated at FCECON, from 2016 to 2020, showed that the largest number of cases occurred in females (62.7%); the mean age of patients was 54.0 ± 16.2 years (range 0 to 105 years); the most frequent topography was breast (27.9%) and the least frequent, urinary tract, kidney and adrenal (1.5%); the most frequent reason for indicating the IHC exam was to obtain a differential diagnosis (48.0%); the median number of antibodies per exam was 5 (range 1 to 23 antibodies); the median time elapsed between the initial diagnosis by histopathological examination and the final diagnosis by IHC was 48 days (range 30 to 88 days). Conclusion: The analysis of immunohistochemical reports over a five-year period allowed us to understand the epidemiological profile of neoplasms diagnosed by IHC at FCECON, highlighting the need to perform immunohistochemistry test as a necessary tool for the complete diagnostic and prognostic definition of cancer patients, and providing data to support the planning of public health strategies for patients who depend on the SUS for their treatment, regarding the performance of these exams in the state itself or outsourced partnerships, considering the costs involved and aiming at better care for cancer patients in Amazonas.