The progressive increase in life expectancy of cancer patients, which is associated with the development and availability of newer more effective therapies has raised the prevalence of cancer in our society ^{1, 2} . Even though recent therapies, such as immunotherapy, tend to have an improved side-effect profile ³ , patients still suffer from stigma and progression of the disease, especially those with incurable conditions. Good outpatient care is a crucial component of the treatment of the oncologic patient, and emergency department (ED) visits are a strong indicator of low quality of life among cancer patients ⁴ . Other authors have studied the profile of cancer patients in general hospitals and through registries ^{5– 9} . The use of secondary data can sometimes lead to information bias ¹⁰ . We aim to understand what drives ED utilization among cancer patients in an oncology teaching hospital using primary source data.

Patient demographics are shown in Table 1.

This study registered 277 consecutive ED visits to Araújo Jorge Hospital, an oncology-only teaching hospital. The main limitations of the study are the absence of staging information and the fact it is based in a single institution. Its strength resides in the quality of data - collected for primary use - and despite the limited number of visits, it shows that pain is the main driver of patients with cancer to the ED, corroborating findings of previous studies with larger numbers from secondary use data ^{6– 9} . Demographic analysis showed that the hospital is a strong regional reference for oncologic care, serving patients not only from the mid-west but also from the north and northeastern regions. There were no patients from the south or southeastern regions of the country.

Abdominal pain was the most common single complaint with 18.4% of all visits; patients with these complaints were more likely to return with the same complaint than others, leading to more frequent visits than those with different complaints. One possible explanation is that abdominal pain unites complications from many different organs and systems, including tumors from the most common sites (see Table 4). Also, its higher frequency can be at least in part explained by the higher frequency of cervical cancer in our population, which commonly complicates with intra-abdominal and pelvic metastasis.

Complaints at the current visit was the same as the last visit in 55.2% of times, revealing the opportunity to predict the chief complaint of future visits, especially in the case of abdominal pain. In practice, nausea and vomit are major complaints of this population, but it ranked only sixth in this study, this is possibly explained by either easier good outpatient control or not enough severity to bring patients to the hospital.

In our study, cervical cancer had the highest frequency in the ED, with 14.8% (n=41) of all cases, followed by breast, lung and colorectal cancers, with 11.6% (n=32), 7.6% (n=21) and 7.6% (n=21), respectively. Another Brazilian study, Borges et al. ⁶ also found cervical cancer as the most common at the ED, and almost two-thirds of the patients had one of the following primary tumors: urological, breast, gastrointestinal tract and lung cancer. In contrast, most studies found lung cancer as the major driver of visits, followed by breast and colorectal tumors ^{5, 7, 11, 12} . This inequality is associated with low-resource settings with suboptimal programs such as screening and vaccination ¹³ . According to The Brazilian Cancer National Institute (INCA), cervical cancer has high incidence and prevalence in Brazil, and it is estimated to be responsible for 70% of the total of uterine cancer. Furthermore, although it’s ranked third in incidence in the country, it is the second in the mid-west region of the country, where this study was performed, responsible for 11.4% of all female malignancies. In parallel, in the US, only 17% of uterine cancers are expected to originate from the cervix, according to public domain reports from the National Cancer Institute Surveillance, Epidemiology, and End Results Program. This disparity should encourage more focus on preventive measures, such as better vaccination rates against HPV and Pap smear coverage in Brazil ¹³ . Despite not being the most incident, melanoma was the most common skin cancer leading to ED usage, likely due to its higher aggressiveness and invasion potential than other skin cancers.

We found a high rate of patients with multiple visits, including 10% of patients reporting daily visits. More than half of patients (63.8%, n=172) visited the ED in the previous month. These are findings that differ from Leak et al. ¹² , who showed that 71% of the patients had visited the ED only once before their death. The absolute majority (95%) of patients were insured by Sistema Único de Saúde (SUS), the Brazilian public health system, therefore suggesting low-income population, with limited access to costly pain medications; requiring some of our patients to come to the ED on a daily basis for analgesia. In addition, cultural behavior limits goals of care discussions, causing a significant barrier to adequate end-of-life care. In this scenario, the expansion of the role of pain clinic and palliative care initiatives could immensely benefit patients by easing the dying process. Good outpatient symptom control could lead to decrease of ED utilization. Furthermore, this study once again highlights the importance of pain management in oncology, as a major topic in the field, and as such, it should be given extra emphasis in oncology training. More research is needed for the development of new therapies for pain in cancer patients.

The research meets all applicable standards with regard to the ethics of experimentation and research integrity, and the following is being declared true. As an expert scientist and along with co-authors of concerned field, the paper has been submitted with full responsibility, following due ethical procedure, and there is no duplicate publication, fraud, plagiarism, or concerns about animal or human experimentation.

IRB approval number: CAAE: 43909215.7.0000.0031

The data referenced by this article are under copyright with the following copyright statement: Copyright: � 2017 Batalini F et al.

Data associated with the article are available under the terms of the Creative Commons Zero "No rights reserved" data waiver (CC0 1.0 Public domain dedication).

Dataset 1: Cancer patients presenting at the emergency department in Brazil. Doi, 10.5256/f1000research.12632.d182277 ¹⁴