Colorectal cancer (CRC) is second only to lung cancer in being the most common cause of cancer registration and deaths in New Zealand and with an ageing population, the absolute number of people with CRC in New Zealand is expected to increase.1
CRC fits most of the World Health Organization criteria for a population screening programme.2 In 1997, the New Zealand National Health Committee convened a working party to look at population screening and at that time recommended that such a programme not be considered because of inadequate resources within New Zealand, as well as the fact that they considered that the benefit would only be a modest one and that there was potential for harm.3 Instead, New Zealand opted for surveillance guidelines4 which would identify those at increased risk of CRC who could then be referred for surveillance colonoscopy.
People identified for surveillance colonoscopy have, however, experienced long waiting periods before being tested because the current health services cannot meet the existing need5. Despite this current pressure on public health services, the Ministry of Health’s Bowel Cancer Team have continued to discuss the issue of CRC screening with health providers and the Government is now committed to introducing a 4-year bowel screening pilot in 2011 to determine whether a bowel screening programme should be rolled out nationally.6
The proposed screening test is the immunochemical faecal occult blood test (FOBT) with those testing positive going on to colonoscopy.
The aim of this paper is to explore the views of GPs and specialists on CRC screening. To date, no other New Zealand study has questioned health professionals in-depth on their attitudes and perceptions towards surveillance and screening for CRC. This highlights the importance of this research as their buy-in would have an impact on implementation and uptake of such interventions in New Zealand.
Research done in Australia suggests that medical practitioners are supportive of CRC screening programmes, particularly if provided through general practice.7 Studies have shown that GP involvement has an impact on uptake of screening,8,9 although Federici et al8 qualify this claim by pointing out that whether GPs are effective in improving compliance depends upon whether they are willing to be involved.
Beliefs about the effectiveness of the different screening tests for CRC also play a role, with a US study finding that there are significant concerns regarding the accuracy of the FOBT,10 although in the Australian context, several studies indicate increasing sympathy with FOBT over time.11,12
As well as concerns regarding the role of GPs and the accuracy of the FOBT, there have also been concerns expressed by medical professionals about the increased demand on already over-stretched public health services.7
The majority of specialists and GPs thought that in theory a population-based CRC screening programme was a good idea, yet they saw this as being idealistic. They perceived such a programme to be unrealistic primarily due to lack of resources and they also had concerns about what they perceived to be the low sensitivity and specificity of the FOBT. Another concern held by the GPs in relation to both the above mentioned themes was the possibility of engendering anxiety in their patients.
Resourcing a screening programme—Lack of resources include a concern by both groups about the shortage of colonoscopists in the public system to cope with a population screening programme, and a concern by the GPs regarding the lack of financial compensation when they are likely to have to bear the responsibility of promoting and monitoring the screening programme.
If a population-based screening programme was to be introduced, specialists perceived that it was the GP’s job, as the ambulance at the bottom of the cliff, to communicate risk of CRC to patients and recommend screening. Specialists saw themselves as just there to deal to people at the bottom of the cliff:
The GPs agreed that they were the best source to deliver information on screening to their patients; however, they were concerned about the lack of resources to carry out this role as there were not the financial resources to do so:
But notwithstanding financial issues, GPs were concerned about bringing up the topic of screening for other reasons, including a reluctance to increase patient anxiety:
Screening was also a difficult concept for some GPs to explain to patients especially when they were not convinced of the benefits of screening:
Both groups argued that there would be insufficient resources to deal with the many anticipated follow-up colonoscopies:
Both GPs and specialists identified the increasingly long waiting list in the public system for people requiring colonoscopies at present, which would be compounded after the introduction of a screening programme:
In response to their concerns about resourcing, specialists and GPs argued that it would be more beneficial to have a targeted screening programme aimed only at those at increased risk or rather than a recall system, provide a one-off colonoscopy to people at the age of 50:
Colonoscopy was seen as the gold-standard test of choice for CRC screening, especially by specialists:
This specialist argued that colonoscopy was a preferred choice of screening tool to the FOBT because of the greater specificity it provided.
Test sensitivity and specificity—As mentioned previously, the screening test proposed in New Zealand is the immunochemical FOBT with individuals testing positive going on for colonoscopic investigation. The immunochemical FOBT has a higher sensitivity and specificity than the guaiac FOBT.
Participants were asked about FOBT screening in general, not specifically on their thoughts on guaiac and immunochemical FOBTs. Most GPs did not differentiate between the two and talked about FOBT tests in general having a low specificity and sensitivity:
Few specialists, too, differentiated between the different types of FOBT:
One specialist acknowledged that there were different types of FOBT but was unsure about which one would be used in the proposed screening programme, implying that neither was optimal:
Similar to the discussion on screening with patients, GPs were concerned about the heightened anxiety false positives would engender in their patients which reinforced in their minds the lack of merit in doing an FOBT:
Some GPs argued that FOBTs did not feature in their decision-making about referral for screening but “if the person has got risk factors, they need the screening whether or not the faecal occult blood’s positive or not” (GP11). Many GPs instead indicated that they would currently refer patients for CT colonography as a first step instead of FOBT as they perceived the sensitivity and specificity of that test to be superior to FOBT:
There was a lot of support by GPs for CT colonography whether or not their patients were drawn from low or high socioeconomic areas. It was seen as less invasive and risky than colonoscopy with no likelihood of perforation, more reliable in picking up abnormalities than FOBT and, in addition, would pick up other abnormalities which both FOBT and colonoscopy would miss.
The specialists, on the other hand, did not see this as an advantage and as well as being concerned about the risk of radiation, argued that the increased cost to the screening programme through picking up other abnormalities was not warranted.
The holistic nature of general practice and the relationship of trust between patient and GP meant that the concerns of GPs regarding the merits of particular tests were not echoed by those of the specialists. This may have implications in the implementation of a CRC screening programme in New Zealand.
The study findings generally support those international studies which indicate that GPs are supportive of screening7; have concerns about the accuracy of FOBT,10 may not be convinced that capacity exists to introduce the programme7 and have concerns about screening engendering worry for patients which is a concern also supported in the literature in relation to mammographic screening.18 But, significant effort is likely to be required to ‘sell’ a screening programme to New Zealand GPs and specialists that has as its point of entry the FOBT.
GPs, especially, perceived the sensitivity and specificity of FOBT to be low but it is most likely that these perceptions were based on the guaiac FOBT which until recently has been the standard test used in New Zealand. The proposed screening programme in New Zealand would make use of the newer immunochemical FOBT which has a higher sensitivity and specificity for detecting left-sided CRC and also does not require the dietary restrictions called for by older tests.16
The fact that participants were not questioned directly on the different types of FOBT is a potential limitation of the study, but their responses do also highlight the need for up-to-date information on contemporary forms of FOBT. It may also be the case, as has been found elsewhere, that GPs become more confident about the use of FOBT over time11,12
The GP advocates for and acts in the best interests of their patients.17 Family GPs, because of the ongoing relationship with their patients and their families, develop a relationship of trust and it is more likely that their advice on risk and need for screening would hold more weight than information from an unknown other.
In order for GPs to have some confidence in advocating screening to patients, they obviously need to be convinced that the process is worthwhile. The issue of the role of GPs in the implementation of a screening programme for CRC and the potential increase in their workload and responsibilities as a result, needs to be addressed.
The concerns of both GPs and specialists surrounding resourcing in relation to the physical availability of colonoscopic services also need to be addressed. This is particularly important in the case of the GPs as it became clear from the other participants (members of the public) in the wider research project of which this is a part, that they still very much respect the advice of their family doctor. In giving this advice, GPs are cognisant of not wanting to unnecessarily engender patient anxiety and because of their ongoing relationship, are concerned to do the best for their patients.
If GPs are to have confidence in promoting the programme, then they need to be convinced that it will work for their patients.