The West London Medical Journal 2009 Vol No 1 pp 23-31 COLORECTAL SCREENING PROGRAMME: IMPACT ON THE HOSPITAL S PATHOLOGY SERVICES SINCE ITS INTRODUCTION. Competing interests: None declared ABSTRACT Sarah E Reynolds, Caroline Finlayson Aims: This study examined the impact of introducing the colorectal cancer screening programme on our hospital s pathology service. Methods: We compared the workload figures and main histological diagnoses found in biopsies from 82 patients referred for colonoscopy through the colorectal cancer (CRC) screening programme in January-June 2007 with those from 80 patients referred with lower GI symptoms (e.g. change in bowel habit) in the corresponding period in 2006. The absolute numbers of biopsies taken were compared to reflect the increase in patient numbers as a result of the introduction of the screening programme. Results: There was a 69.5% increase in specimen numbers in 2007 as a result of screening. FOB positive (Faecal Occult Blood) patients generated a significantly higher mean Welcan units per referral (p<0.05). FOB positive patients had a significantly larger mean maximum sample size (p<0.05). The main diagnoses made on the biopsies sent from the pre-screening group were normal mucosa (39.04%) and tubular adenoma (32.93%) with relatively few adenocarcinomas in this group (4.89%). On the other hand, in the FOB positive group, only 6.25% of the biopsies were histologically normal; the primary histological diagnosis for nearly half the patients was tubular adenoma (48.75%) and 10% of biopsies showed adenocarcinoma. Conclusion: Screening has significantly increased the workload of the histopathology department. A higher proportion of biopsies showing adenomatous polyps and adenocarcinoma were detected in the screening group, compared with patients who presented with lower GI tract symptoms. 23
INTRODUCTION 50% of CRC (colorectal cancer) cases occur in people aged 60-69 years 1. Screening for colorectal cancer (CRC) using the faecal occult blood (FOB) test involves sending home testing kits biannually to adults in this age range, but patients aged >70 can participate by request. Pilot studies have shown that approximately 2% of individuals test positive and are sent for further investigation by colonoscopy (or barium enema if colonoscopy is not possible). Our hospital entered the screening programme in November 2006. Only one biopsy was received in December 2006, so our study examines the first 6 months of 2007. Price et al 2 demonstrated that the screening programme had a significant impact on hospital diagnostic services. The paper (based on audit data and questionnaire responses) showed an increased usage of the colonoscopy services of 21-31% as a result of investigating the FOB positive patients. The impact of the CRC screening trial at the primary care level was examined in a retrospective survey and audit by Jepson et al 3. The authors demonstrated an increase in primary care workload (mainly advice and information provision) as a consequence of the introduction of CRC screening program. We were interested to see what impact CRC screening would have on the histopathology department. Method The pathology reports were obtained for all 80 screening-detected FOBt (test) positive patients biopsied at colonoscopy during the period Jan 07 Jun 07 (the initial stages of our hospital s participation in the NBS programme). The eligibility for participation in the NBS programme is people aged 60-69 years, but people aged over 70 years can also request test kits from their GPs. Sixteen patients were over 70 years. We compared the CRC screening group with the 82 symptomatic patients aged 60-69 years referred to colonoscopy for investigation of symptoms such as change in bowel habit or anaemia during the period Jan 06 - Jun 06 (choosing the previous year ensured that there could be no confusion between the patient populations). This age group was selected in order to make the target groups comparable. Only patients referred for symptomatic investigation were included; those seen for routine surveillance (e.g. known inflammatory bowel disease or with a previous history of adenomatous polyps or lower gastrointestinal tract cancer) were excluded. 24
The workload impact of the CRC screening programme on pathology services was examined in terms of Welcan units for the biopsies taken in the two patient groups over each six month period. Welcan units measure the laboratory impact of specimen processing, cutting and staining, the number of levels taken through the block and any extra stains. For the purposes of this study the pathology from the symptomatic patients presenting in 2006 was compared with that from the screening patients in 2007. The following parameters were considered as measures of trial impact: 1) Absolute number of colorectal biopsy reports issued during the periods Jan-Jun 06 and Jan-Jun 07; 2) Welcan units unit of pathology workload; 3) Number of sample pots; 4) Histological sample size. Methodological points: Patients who presented more than once in the same period were counted as separate events. A specimen included all biopsies taken from a patient during one endoscopy thus the number of sample pots per patient varied between specimens. Only colorectal samples were included in the study (separate terminal ileal biopsies were excluded). Results. Specimen numbers: There was a 69.5% increase in specimen numbers in the first six months of 2007 compared the same time period in 2006 (figures 1.1 and 1.2). The total number of symptomatic patients aged 60-69 years seen in 2007 (n=59) slightly decreased compared to those seen in the first six months of 2006 (n=82). Workload: workload was measured in Welcan units (table 2). As data was not normally distributed a Mann-Witney U test was performed to establish whether the two groups were drawn from similar populations. Null hypothesis: pre-screening and screening patients were drawn from the same population regarding Welcan units per referral. 25
Alternative hypothesis: pre-screening and postscreening patients were drawn from different populations regarding Welcan units per referral. P equalled 0.001, therefore as p<0.05 the null hypothesis was rejected and it was concluded that there is a statistically significant difference at the 5% level between the two populations. Number of sample pots: the number of sample pots sent to pathology per referral in the two groups is shown in table 3. There was no significant difference between the groups. Maximum sample size: The maximum sample size in each referral is shown in table 4. A Mann-Witney U test was performed to see if the two groups were drawn from different samples regarding to maximum sample size. Null hypothesis: pre-screening and screening patients were drawn from the same population regarding maximum sample size per referral. Alternative hypothesis: pre-screening and screening patients were drawn from different populations regarding maximum sample size per referral. P equalled 0.049 therefore as p<0.05 the null hypothesis is rejected, i.e. there is a significant difference between the two groups with regards to maximum sample size at the 5% level. Histological diagnosis: A summary of the main histological diagnoses made in the biopsies from the two patient groups is shown in Table 5. Ranking of histological diagnosis is as follows: 1) Adenocarcinoma 2) Tubular adenoma 3) Tubulovillous adenoma 4) Serrated adenoma 5) Hyperplastic polyp 6) Inflammatory bowel disease 7) Angiodysplasia 8) Non-adenocarcinoma malignancy 9) Miscellaneous diagnoses 10) Normal Geographical distribution: We also compared the locations within the colon at which neoplastic polyps and cancers were encountered in the two groups. Although there were slightly more right sided and slightly few left 26
sided lesions in the FOB positive group, the findings were not significantly different. DISCUSSION The efficacy of the FOBt screening method in reducing colorectal cancer mortality was confirmed in a review of the Denmark arm of the FOBt trail 4 showed a significant reduction in the risk of CRC mortality in the screening group compared to the general population over a thirteen year period. The Nottingham hub also showed that FOBt diagnosed a higher proportion of CRC tumours of a less advanced stage than those which presented symptomatically over a ten year period 5. The staggered introduction of the screening programme to UK hospitals followed a review of trials by the national screening committee (NSC) 6 confirmed the efficacy of the FOB screening test. In this study we found a 69.5% increase in specimen numbers in patients aged 60-69 years (the target age for bowel cancer screening) in 2007, reflecting an increase in patients as a result of screening (16 patients in the screened group were >70 years old and had opted in to the programme). Several characteristics were used to compare the screening-detected FOB positive patients with an equivalent symptomatic patient group from the prescreening era. In terms of the laboratory workload, FOB positive patients were found to have significantly higher mean Welcan units per referral. There was no significant difference between the two populations with respect to number of pots sent to pathology. However, FOB positive patients had a significantly larger mean maximum sample size. Although the analytical aspects were not formally addressed, an informal discussion with the pathologists involved in reporting the screening specimens indicated that the interpretation of torted, inflamed and ulcerated polyps from the group with positive FOB tests was more problematic. In particular, the differentiation of true invasive malignancy from pseudoinvasion due to torsion, added considerably to the time required for slide interpretation. Multiple levels were routinely employed in the FOB positive group in order to speed up the turnaround time to comply with the screening target, whereas levels were used more judiciously in the symptomatic group. The most surprising difference between the two study groups was that of the main (most significant) histological diagnosis. The main diagnoses made on the biopsies sent from the pre-screening group were normal mucosa (39.04%) and tubular adenoma (32.93%) with relatively few adenocarcinomas in this group (4.89%). In the FOB positive group, only 6.25% of the biopsies 27
were histologically normal; the primary histological diagnosis for nearly half the patients was tubular adenoma (48.75%) and 10% of biopsies showed adenocarcinoma. CONCLUSION Following the introduction of the screening program there was a 70% increase in colorectal biopsy specimen numbers over the six months (Jan-Jun) period in 2007 compared with the previous year. The workload (Welcan units) generated by the FOB positive (screening) patients was significantly higher, reflecting the increased mean maximum sample size per referral (larger polyps and biopsies take longer to examine histologically). Interestingly, samples from the FOB positive patients tended to be larger and more complex than those from the symptomatic patients, requiring more in-depth histological interrogation. A pleasing finding was the significant reduction in the number of normal biopsies received in the FOB positive group, compared with the high percentage obtained from the symptomatic group. A higher proportion of adenomatous polyps and adenocarcinomas were detected in the FOB positive patients confirming that the screening programme was effective in detecting cancerous and precancerous lesions. Due to the increased complexity of the screening programme samples, the programme s introduction represents a significant increase in pathology workload in this centre. Acknowledgements and thanks must go to Dr Finlayson (Pathology) and Mr Leicester (Endoscopy) and the Endoscopy Unit staff at St George s Hospital for their assistance and for allowing me access to their data. 28
APPENDIX Table 1. Colorectal biopsy patients in the first 6 months of 2006 and 2007 * Of the FOB positive (n=80) patients sixteen were seventy or over at the time of pathology referral Pre-screening (Jan-Jun 2006) Postscreening (Jan-Jun 2007) Total number of pathology reports 82 100% 139* 42.45% Percentage of pathology reports from symptomatic patients Table 2: Welcan units per referral Pre-screening (n=82) FOB positive (n=80) Mean (mm) 87.22 128.80 Standard Deviation 78.126 121.107 Range 32-483 37-642 Table 3: Number of pots per referral Pre-screening Symptomatic patients (n=82) Screening FOBpositive Patients (n=80) Mean 1.82 2.09 Standard 1.177 1.451 Deviation Range 1-7 1-9 Sum 149 167 29
Table 4: Maximum sample size per referral Prescreeing (n=82) FOBpositive (n=80) Mean (mm) 4.24 5.89 Standard Deviation 3.836 5.259 Range 1-40 1-25 Table 5: Summary of main histological diagnoses Prescreening 2006 Screening 2007 (n=80) (n=82) Adenocarcinoma 4 8 Tubular Adenoma 27 39 Tubullovilous 5 7 Adenoma Hyper/Metaplastic 11 8 Polyp Inflammatory Bowel 1 5 Disease Angiodysplasia 1 Other cancers 1 Miscellaneous 1 6 Normal 23 5 References 1. Lieberman D, Sleisenger MH. Is it time to recommend screening for colorectal cancer? Lancet 1996;348:1463 4. 2. Price J, Campbell C, Sells J, Kenicer M, Dunlop M, Weller D, Campbell H. Impact of UK Colorectal Cancer Screening Pilot on hospital diagnostic services Journal Public Health 27:3 p246-53 2005. 3. Jepson R, Weller D, Alexander F, Walker J. Impact of UK Colorectal Cancer Screening Pilot on primary care British Journal General Practice 2005 Mar; 55(512):234. 4. D Jørgensen, O Kronborg and C Fenger. A randomised study of screening for colorectal cancer using faecal occult blood testing: results after 13 years and seven biennial screening rounds. Gut 2002 Jan; 50(1):29-32. 30
5. Hardcastle JD, Thomas WM, Chamberlain J, et al. Randomised controlled trial of faecal occult blood screening for colorectal cancer: the results of the first 107 349 subjects. Lancet 1989; I : 1160 4. 6. National Screening Committee. A summary of the colorectal cancer screening workshops and background papers, 1998. Available at http://www.nsc.nhs.uk/pdfs/summary_colorectal.pdf. 31