Knowledge and practice of physicians regarding colorectal cancer screening

ORIGINAL ARTICLE

Knowledge and practice of physicians regarding colorectal cancer screening

Elziane da Cruz Ribeiro e Souza^I; Marina Lise^I; Thalita Pereira dos Santos^I; Luciano Pinto de Carvalho^II

^IPhysicians graduated by Universidade Luterana do Brasil – Canoas (RS), Brazil

^IIPhD in Gastroenterology Sciences; Expert in Coloproctology; Adjunct Professor at Universidade Luterana do Brasil – Canoas (RS), Brazil

^{Correspondence to}

ABSTRACT

INTRODUCTION: Despite the high prevalence and high rates of mortality of colorectal cancer, it is likely to be a secondary prevention disease due to the presentation of characteristics that are ideal for a successful screening program, with a proven positive impact on its outcome.

OBJECTIVE: To describe the knowledge and practice of physicians concerning screening tests for the prevention of colorectal cancer.

METHODS: Cross-sectional study carried out between November 2011 and February 2012, through a questionnaire administered to 83 physicians who assist adult patients at the University Hospital of Universidade Luterana do Brasil and at basic health units of Canoas, Rio Grande do Sul, Brazil.

RESULTS: From the number of physicians participating in the survey, only 35 (42.0%) reported prescribing tests for colorectal cancer screening. Out of these, only 21 used the screening on patients aged 50 years old or more, as recommended by the guidelines. Only 65.0% of the physicians reported investigating family history of colorectal cancer, and surgical experts were the ones who least investigated this risk factor (p=0.005), when compared with clinical and gynecology specialties.

CONCLUSIONS: The number of physicians who reported ordering tests for the prevention of colorectal cancer is still low, and their knowledge regarding the recommendations of the guidelines is very limited. The results indicate the immediate need for investment in professional formation and medical staff training concerning preventive measures for colorectal cancer.

Keywords: colorectal cancer; prevention; screening; physicians.

RESUMO

INTRODUÇÃO: O câncer colorretal, apesar de apresentar alta prevalência e elevadas taxas de mortalidade, é uma doença passível de prevenção secundária, devido ao fato de possuir características ideais para um programa de rastreamento bem-sucedido.

OBJETIVO: Estudar o conhecimento e a prática dos médicos sobre o rastreamento e a prevenção secundária do câncer colorretal.

MÉTODOS: Estudo transversal, realizado entre novembro de 2011 e fevereiro de 2012, por meio de um questionário aplicado a 83 médicos que atendem diretamente pacientes adultos no Hospital Universitário da Universidade Luterana do Brasil e em unidades básicas de saúde de Canoas, no estado do Rio Grande do Sul.

RESULTADOS: Do total de médicos participantes da pesquisa, apenas 35 (42,0%) afirmaram solicitar exames de rastreamento do câncer colorretal e desses somente 21 iniciam o rastreamento a partir dos 50 anos, que é a idade recomendada pelas diretrizes. Apenas 65% dos médicos declararam investigar história familiar de câncer colorretal, sendo os especialistas cirúrgicos os que menos afirmaram investigar tal fator de risco (p=0,005), quando comparados com as especialidades clínica e ginecológica.

CONCLUSÕES: O número de especialistas que afirmaram solicitar exames de prevenção do câncer colorretal foi baixo, e seu conhecimento quanto às recomendações das diretrizes se mostrou muito limitado. Os resultados apontam para uma necessidade imediata de capacitação e treinamento da classe médica sobre prevenção do câncer colorretal.

Palavras-chave: câncer colorretal; prevenção; rastreamento; médicos.

INTRODUCTION

Colorectal cancer (CRC) involves malignant tumors that affect the colon and the rectum, thus constituting all over the world the third most common cause of cancer among males and the second among females¹. The National Cancer Institute (Inca) estimates that, in 2010, the Brazilian population was affected by more than 28,000 new cases of such cancer and, in 2012, 30,140^2,3.

Mostly (70 to 90% of the cases), CRC comes from adenomatous polyps, according to the adenoma-carcinoma sequence, which slowly progresses in about ten yeras^4,5. Even though this long period of evolution offers an opportunity to prevent CRC, it is clinically silent; that is, diagnosis and the consequent interruption of the evolution to a malignant lesion can only happen by the performance of screening tests, which are able to identify the adenomas, or even the carcinomas, in early stages⁶.

Screening is a secondary form of prevention that uses tests of asymptomatic subjects for the presumptive identification of the disease, which is still unknown⁷. A study from 2010 pointed CRC screening as the cancer with greater chances of success, in terms of prevention and early detection⁸. This is due to the oncogenic peculiarities of this type of cancer and the availability of effective screening methods, which allow the identification and, consequently, the treatment both for precursor lesions (preventing CRC) and malignant tumors at early stages, with the confirmed reduction of mortality incidence and rates caused by the disease⁹.

Literature shows that the incidence of CRC can be reduced in up to 90% when the detection and the removal of pre-malignant lesions occur¹⁰. Likewise, the survival of patients submitted to screening tests diagnosed with malignant lesions at early stages reaches 90% in five years^11,12.

In the United States, which has an effective system of prevention and vigilance, it was observed that between 2003 and 2007 there was a 13% decrease in CRC incidence, and a 12% decrease in mortality, which means the reduction of about 66,000 cases and 32,000 deaths in comparison with 2002¹³.

Contrarily to what is observed in the USA, data from the Department of Data Processing of the Unified Health System (DATASUS) show that the mortality rate by CRC in the total of deaths caused by cancer in Brazil has increased. Rates ranged from 11.6%, from 1989 to 1993, to 14.5%, from 2003 and 2007¹⁴.

The increasing rates of this type of cancer in Brazil and the higher mortality levels throughout the years indicate a flaw in screening and prevention. Among the explanations for this situation, there are medical unawareness and/or the non-application of recommended preventive measures.

A study conducted in São Paulo concerning the doctors' attitude towards prevention and screening of the most prevalent types of cancer showed that CRC was the type that doctors were less concerned about in terms of prevention. When performing it, the adopted screening methods were those that most diverged in relation to the recommendations in the guidelines¹⁵.

A research aiming to determine the obstacles to CRC screening showed that the indication from a doctor is the factor that most influences the adhesion of the patient to screening tests for this type of cancer¹⁶.

Considering that the medical class constitutes the main instrument of CRC prevention, and that the unawareness of these professionals concerning screening is one of the barriers to control the incidence and mortality caused by this cancer, this study aimed to analyze the medical knowledge and practice in relation to CRC screening and secondary prevention.

METHODS

It is a cross-sectional study performed between November 2011 and February 2012. The study population was comprised of 83 doctors who assisted adult patients in the University Hospital of Universidade Luterana do Brasil (ULBRA) and in basic health units of Canoas, Rio Grande do Sul, who agreed to participate in the study. Doctors were randomly selected.

Data collection was based on a self-employment questionnaire composed of open and closed questions concerning the characterization of the study population and the medical knowledge and practice related to CRC prevention.

The analyzed variables to characterize the study population were: year and university of graduation, specialty, place of work (University Hospital – ULBRA and basic health units of Canoas); place of assistance (outpatient client and admission) and income source of medical care. The other variables included: ordering tests for CRC screening and the indication factor of the request, requested examinations, reason to choose the exam, investigation of family history of colorectal cancer, screening for other types of cancer and heart disease.

Time of formation was described by median and interquartile amplitude (percentiles 25–75), due to the asymmetric distribution of such variable. The other variables were described by absolute and relative frequencies and the association between them was assessed by the χ², Pearson or Fisher's exact test.

The analysis of the answers concerning the knowledge about CRC prevention was based on guidelines of polyp and CRC screening from the Agency for Health Care Policy and Research (Chart 1)¹⁷.

The adopted significance level was 5% (p≤0.05), and the analyses were performed with the software Statistical Package for the Social Sciences (SPSS), 18.0.

Data collection and analysis were conducted only after the approval from the Human and Animal Research Ethics Committee of ULBRA, protocol 2011-248H.

The participants were enlightened as to the nature of the study, the voluntariness of the participation, and then they signed the informed consent form and received a copy of it. Identity preservation was assured by such term. The study followed the determinations of Resolution 196, from the National Health Council.

RESULTS

The questionnaire was answered by 83 doctors; 76% of them worked at the University Hospital, and 24% in basic health units of Canoas. As to the characterization of the sample, 100% of the doctors graduated in medical schools from Rio Grande do Sul and presented with median nine after graduation (P25–P75=3–20). Around 60% of them had clinical formation, with specialties distributed according to Table 1, and 72.3% of them had professional connections with the medical school institution. Most of them worked concomitantly in outpatient clinics and admission and, at the same time, both for the Unified Health System (SUS) and for private health insurance companies (Table 1).

Out of the total number of doctors participating in the study, about 80% confirmed they knew about CRC screening, but only 35 of them (42.2%) declared ordering any prevention examination for this cancer during routine elective care.

Among the 35 doctors who reported ordering tests for CRC screening, most of them stated this request was based on family history of this type of cancer. However, only 60% of them reported ordering it for the population aged 50 years or older, according to what is recommended by the guidelines (Chart 1)¹⁷.

When these doctors were asked about which CRC prevention tests they order, most of them chose more than one option. The most indicated examinations were colonoscopy and the fecal occult blood test, 83 and 73%, respectively. Efficiency was the most indicated reason for choosing these examinations (Table 2). However, at the separate analysis of how many doctors order only colonoscopy as a test to prevent CRC, the frequency decreased from 83 to 40%.

Out of all the doctors who answered the questionnaire, only 65% stated investigating family history of CRC in patients without bowel complaints. More than 90% said they knew which the examination of choice for CRC prevention was and 82.7% mentioned colonoscopy as the examination of choice.

Most doctors, 84%, declared ordering tests or referring asymptomatic patients to screen for other types of cancer, and breast, uterine and prostate cancer are the ones that are mostly screened for: 88.7, 84.5 and 69%, respectively. Likewise, almost 90% of the doctors reported screening for heart disease in asymptomatic patients during routine care (Table 3).

It was observed that doctors who performed CRC screening were the ones who mostly responded having knowledge concerning screening (p=0.043), and also the ones who mostly stated investigating family history of this cancer (p=0.002) in relation to other doctors.

It was also found that 98.5% of the doctors with knowledge concerning CRC declared to know the examination of choice for screening, while amongst the ones who claimed not having this knowledge, only 62.5% reported knowing which was the examination of choice to prevent this cancer (p<0.001).

All variables were analyzed according to the specialties, and those which presented a statistically significant difference are shown in Table 4. Surgical experts, when compared to the others, are the ones who least analyze family history of CRC (p=0.005). Obstetrician-gynecologists pointed the efficiency as a reason to choose the screening test with less frequency (p=0.016). Besides, they mentioned more times the fecal occult blood test as the method of choice for the secondary prevention of CRC, to the detriment of colonoscopy.

An association between knowledge concerning CRC declared by the professional and time of graduation was found (p=0.028). Doctors who had been graduated for more than 15 years were the ones who mostly declared not knowing about CRC screening, as presented in Figure 1. They also investigated uterine cancer less frequently when compared to other doctors, who had been graduated for a fewer years (p=0.048).

Doctors graduated more recently (less than five years) were the ones who mostly stated ordering screening tests for prostate cancer (95.2%), when compared to those who have been graduated from five to ten years (55.6%), from 10 to 15 years (66.7%) and more than 15 years (56.5%), with p=0.019.

Concerning work location, it was observed that doctors from basic health units declared ordering more examinations to prevent uterine and prostate cancer than the doctors in the university hospital (p=0.030; p=0.011). However, no significant differences were found between these work places and CRC screening.

This study did not find statistically significant differences between the knowledge and practice of doctors concerning CRC screening and prevention, university of graduation, professional connections with the medical school institution, work place (outpatient clinic, admission) and the income source of medical care (SUS, private health insurance).

DISCUSSION

Despite presenting high incidence and mortality rates, colonic and rectal cancer can really be prevented by means of screening tests, which are able to detect and remove pre-malignant lesions^1,6. However, this form of prevention is conditioned to a proper medical knowledge and application of the recommended screening examinations.

Out of the doctors who participated in this study, only 42% stated ordering CRC screening and prevention tests. This result corresponds approximately to the double of the data found in 2004 by Tucundava et al., who analyzed doctors in a medical school of São Paulo (20.30%)15. However, it is a much lower result than that found in the United States, which has an effective CRC vigilance and screening system. There, Klabunde et al. found that only 2% of primary care doctors do not order prevention examinations for this type of cancer¹⁸.

The age to start CRC screening ranges, especially at the presence of family history for such disease (Chart 1)¹⁷. However, when this peculiarity is not present, it is common sense among the organizations involved in CRC prevention and control that everyone should start screening at the age of 50, period when its increased incidence is observed^9,19,20. In this study, among the 35 doctors who stated ordering CRC prevention tests, 40% of them do not request it for patients aged 50 years old or more. This information points to the low level of knowledge of the doctors as to the CRC screening indications recommended by the guidelines, and it also confirms the data from a North-American study, which also found many doctors recommending this screening test for patients outside the suggested age group^1,18.

Generally, CRC screening tests can be divided into two categories. One of them is composed by stool tests, which are more adequate to detect cancer, once the pre-malignant lesions, especially small polyps, tend not to bleed, and the larger ones can present intermittent bleeding or simply not be detectable in a stool sample. The other category is represented by endoscopic examinations, especially colonoscopy, which reaches the double objective of detecting adenocarcinoma and adenomatous polyps, thus enabling the treatment of these lesions and, consequently, CRC prevention²⁰.

Since the primary objective of CRC screening is preention, tests that are able to detect both cancer in early stages and pre-malignant lesions should be indicated²⁰. Among the doctors who stated ordering CRC prevention tests in this study, 82.9% indicated colonoscopy as an alternative for screening. However, with the analysis of which ones among them indicate this test exclusively as a prevention method, the frequency decreased to 40%. This information differs from the result found in the United States, where 95% of the doctors order colonoscopy for CRC prevention²¹.

From all the doctors who answered the questionnaire, only 65% stated investigating family history of CRC in patients without bowel complaints, and an even lower frequency was found among surgeons and doctors who declared not performing screening for this cancer. These results show the deficient investigation of this factor, once first degree relatives of people with CRC have twice or three times the chance to develop this type of cancer in comparison with the Control Group. Therefore, a positive family history determines age anticipation to start screening^7,17,19,22.

More than 90% of the doctors participating in this study said they knew which the examination of choice for CRC prevention was, mentioning colonoscopy80% of the time. This result is similar to that found by Klabunde et al. with doctors in the United States, who also see colonoscopy as the most efficient screening method¹⁸. Even though there are no randomized prospective clinical trials analyzing colonoscopy as a method to reduce the incidence and/or mortality by CRC, it is based on indirect but substantial evidence, which recognizes colonoscopy as the most efficient prevention method. The advantages of colonoscopy include the complete colon and rectum examination, the possibility to diagnose pre-malignant lesions (main objective of CRC screening), the performance of biopsy, as well as the removal of adenomas, being the only test that is able to reduce the incidence of this cancer in 66 to 90% of the cases^20,23.

In most studies, the coverage rates concerning CRC screening are low, usually much lower than those related to other cancer prevention programs^7,15. This data was confirmed in this study. While only 42% of all the participating doctors stated conducting CRC screening, which is similar to the double, 84% reported ordering tests or referring asymptomatic patients to screen for other types of cancer.

Breast and uterine cancers are the ones doctors mostly screen for, which confirms the results of another study from São Paulo, which found these two cancers as being the ones doctors are more concerned about preventing¹⁵.

Proportionally to the screening for other cancers, more than the double of doctors participating in the research declared ordering prevention tests for heart diseases in asymptomatic patients. These results are in accordance with the analysis of mortality rates by chronic diseases in Brazil, which point to a 31% reduction in mortality by heart disease between 1996 and 2007, and an increased mortality rate by CRC, both for men and women²⁴.

Nowadays, CRC affects women more than gynecological cancers. Epidemiological studies demonstrated the increased risk of colonic and rectal cancer from 1.5 to 3.0 times in women who have previously had primary malignant neoplasm of endometrium or ovary²⁵. This information points to the need for even more attention from gynecologists to CRC prevention. The American College of Obstetricians and Gynecologists (ACOG) published, in the beginning of 2011, a report encouraging doctors in this specialty to order screening and prevention CRC tests for women aged more than 50 years old, or earlier, according to the risk. This report also recommends colonoscopy as the method of choice for prevention²⁶. Despite that, out of the 16 doctors with this specialty who answered the questionnaire in this study, 56% stated not ordering screening tests for CRC. Besides, when compared to other specialties, they were the ones who most indicated the fecal occult blood test to the detriment of colonoscopy as the examination of choice to prevent such cancer.

In this study, the association between time of graduation and knowledge concerning CRC declared by the Professional stood out. Doctors graduated for more than 15 years were the ones who mostly declared not knowing about CRC screening (Figure 1). This can be related to the fact that guidelines and screening methods have been improved in the past decade, when these doctors had already finished their basic graduation.

The methodological limitations of this study should be mentioned. As demonstrated in previous studies, there is a gap between what the doctors report doing and what he or she actually does²⁷. However, in Brazil there are no studies that assess knowledge and practice of the doctors specifically as to CRC screening and prevention. Besides, the found results confirm the findings in other studies, suggesting that the information presented is valid and interpretable.

CONCLUSION

A small number of doctors participating in this study adopt CRC screening and prevention methods. Besides, they demonstrated low level of knowledge concerning the recommendations in the guidelines for the prevention of this cancer, especially as to the age to start screening.

The results in this study point to the need to invest in professional formation and training of the medical class, emphasizing the importance and the efficacy of secondary prevention to control the incidence and mortality by this cancer.

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Submitted on: 02/06/2011

Approved on: 29/07/2011

Study carried out at the Universidade Luterana do Brasil – Canoas (RS), Brazil.

Financing source: none.

Conflict of interest: nothing to declare.

Publication Dates

• Publication in this collection
  02 July 2013
• Date of issue
  Dec 2012

History

• Received
  02 June 2011
• Accepted
  29 July 2011