Imperial College London


Faculty of MedicineDepartment of Surgery & Cancer

Research Postgraduate







Norfolk PlaceSt Mary's Campus





Publication Type

13 results found

Cross AJ, Robbins EC, Pack K, Stenson I, Kirby PL, Patel B, Rutter M, Veitch AM, Saunders BP, Little M, Gray A, Duffy SW, Wooldrage Ket al., 2022, Colonoscopy surveillance following adenoma removal to reduce the risk of colorectal cancer: a retrospective cohort study, Health Technology Assessment, Vol: 26, Pages: I-+, ISSN: 1366-5278

BackgroundColonoscopy surveillance is recommended for some patients post polypectomy. The 2002 UK surveillance guidelines classify post-polypectomy patients into low, intermediate and high risk, and recommend different strategies for each classification. Limited evidence supports these guidelines.ObjectivesTo examine, for each risk group, long-term colorectal cancer incidence by baseline characteristics and the number of surveillance visits; the effects of interval length on detection rates of advanced adenomas and colorectal cancer at first surveillance; and the cost-effectiveness of surveillance compared with no surveillance.DesignA retrospective cohort study and economic evaluation.SettingSeventeen NHS hospitals.ParticipantsPatients with a colonoscopy and at least one adenoma at baseline.Main outcome measuresLong-term colorectal cancer incidence after baseline and detection rates of advanced adenomas and colorectal cancer at first surveillance.Data sourcesHospital databases, NHS Digital, the Office for National Statistics, National Services Scotland and Public Health England.MethodsCox regression was used to compare colorectal cancer incidence in the presence and absence of surveillance and to identify colorectal cancer risk factors. Risk factors were used to stratify risk groups into higher- and lower-risk subgroups. We examined detection rates of advanced adenomas and colorectal cancer at first surveillance by interval length. Cost-effectiveness of surveillance compared with no surveillance was evaluated in terms of incremental costs per colorectal cancer prevented and per quality-adjusted life-year gained.ResultsOur study included 28,972 patients, of whom 14,401 (50%), 11,852 (41%) and 2719 (9%) were classed as low, intermediate and high risk, respectively. The median follow-up time was 9.3 years. Colorectal cancer incidence was 140, 221 and 366 per 100,000 person-years among low-, intermediate- and high-risk patients, respectively. Attendance at one surveilla

Journal article

Cross AJ, Robbins EC, Pack K, Stenson I, Rutter MD, Veitch AM, Saunders BP, Duffy SW, Wooldrage Ket al., 2022, Post-polypectomy surveillance interval and advanced neoplasia detection rates: a multicenter, retrospective cohort study, Endoscopy, Vol: 54, Pages: 948-958, ISSN: 0013-726X

Background Longer post-polypectomy surveillance intervals are associated with increased colorectal neoplasia detection at surveillance in some studies. We investigated this association to inform optimal surveillance intervals.Methods Patients who underwent colonoscopy and post-polypectomy surveillance at 17 UK hospitals were classified as low/high risk by baseline findings. We compared detection rates of advanced adenomas (≥ 10 mm, tubulovillous/villous, high grade dysplasia), high risk findings (HRFs: ≥ 2 serrated polyps/[adenomas] of which ≥ 1 is ≥ 10 mm or has [high grade] dysplasia; ≥ 5 serrated polyps/adenomas; or ≥ 1 nonpedunculated polyp ≥ 20 mm), or colorectal cancer (CRC) at surveillance colonoscopy by surveillance interval (< 18 months, 2, 3, 4, 5, 6 years). Risk ratios (RRs) were estimated using multivariable regression.Results Of 11 214 patients, 7216 (64 %) were low risk and 3998 (36 %) were high risk. Among low risk patients, advanced adenoma, HRF, and CRC detection rates at first surveillance were 7.8 %, 3.7 %, and 1.1 %, respectively. Advanced adenoma detection increased with increasing surveillance interval, reaching 9.8 % with a 6-year interval (P trend < 0.001). Among high risk patients, advanced adenoma, HRF, and CRC detection rates at first surveillance were 15.3 %, 10.0 %, and 1.5 %, respectively. Advanced adenoma and CRC detection rates (P trends < 0.001) increased with increasing surveillance interval; RRs (95 % confidence intervals) for CRC were 1.54 (0.68–3.48), 4.44 (1.95–10.08), and 5.80 (2.51–13.40) with 3-, 4-, and 5-year intervals, respectively, versus an interval of < 18 months.Conclusions Metachronous neoplasia was uncommon among low risk patients, even with long surveillance intervals, supporting recommendations for no surveillance in these patients. For high risk patients, a 3-year surveillance interval would ensure timely CRC detection.

Journal article

Cross A, Robbins E, Saunders B, Duffy SW, Wooldrage Ket al., 2022, Higher adenoma detection rates at screening associated with lower long-term colorectal cancer incidence and mortality, Clinical Gastroenterology and Hepatology, Vol: 20, Pages: e148-e67, ISSN: 1542-3565

Background and AimsDetection and removal of adenomas reduces colorectal cancer (CRC) risk. The impact of adenoma detection rates (ADRs) on long-term CRC incidence and mortality is unknown. We investigated this using data from the UK Flexible Sigmoidoscopy Screening Trial (UKFSST).MethodsOf 167,882 UKFSST participants, 40,085 were in the intervention arm and underwent flexible sigmoidoscopy screening at 13 trial centres. Median follow-up was 17 years. At each centre, one endoscopist performed most flexible sigmoidoscopies. Multivariable logistic regression was used to classify centres into high-, intermediate-, and low-detector groups based on their main endoscopist’s ADR. We calculated incidence and mortality of distal and all-site CRC, and estimated hazard ratios (HRs) with 95% confidence intervals (CIs) using Cox regression.ResultsFive, four, and four centres, respectively, were classified into the high-detector, intermediate-detector, and low-detector groups. Average ADRs in each respective group were 15%, 12%, and 9%. Distal CRC incidence and mortality were reduced among those screened compared to controls in all groups, and effects of screening varied significantly by detector ranking, with larger reductions in incidence and mortality seen in the high-detector (incidence: HR=0·34, 0·27–0·42; mortality: HR=0·22, 0·13–0·37) than low-detector group (incidence: HR=0·55, 0·44–0·68; mortality: HR=0·54, 0·34–0·86). Similar results were observed for all-site CRC, with larger effects seen in the high-detector (incidence: HR=0·58, 95%CI 0·50–0·67; mortality: HR=0·52, 0·39–0·69) than low-detector group (incidence: HR=0·72, 0·61–0·85; mortality: HR=0·68, 0·51–0·92), although the heterogeneity was not statistically significant.ConclusionsHigher ADRs at scr

Journal article

Harewood R, Wooldrage K, Robbins EC, Kinross J, von Wagner C, Cross AJet al., 2022, Adenoma characteristics associated with post-polypectomy proximal colon cancer incidence: a retrospective cohort study, British Journal of Cancer, Vol: 126, ISSN: 0007-0920

BackgroundColorectal cancer (CRC) screening is less effective at reducing cancer incidence in the proximal colon compared to the distal colorectum. We aimed to identify adenoma characteristics associated with proximal colon cancer (PCC).MethodsEndoscopy and pathology data for patients with ≥1 adenoma detected at baseline colonoscopy were obtained from 17 UK hospitals between 2001 and 2010. Multivariable Cox regression models were used to estimate adjusted hazard ratios (aHRs) and 95% confidence intervals (CIs) for PCC, and, for comparison, distal CRC incidence, by adenoma characteristics.ResultsAmong 18,431 patients, 152 and 105 developed PCC and distal CRC, respectively, over a median follow-up of 9.8 years. Baseline adenoma characteristics positively associated with PCC incidence included number (≥3 vs. < 3: aHR 2.10, 95% CI: 1.42–3.09), histology (tubulovillous/villous vs. tubular: aHR 1.61, 95% CI: 1.10–2.35) and location (any proximal vs. distal only: aHR 1.70, 95% CI: 1.20–2.42), for which there was borderline evidence of heterogeneity by subsite (p = 0.055). Adenoma dysplasia (high vs. low grade) was associated with distal CRC (aHR 2.42, 95% CI: 1.44–4.04), but not PCC (p-heterogeneity = 0.023).ConclusionsBaseline adenoma number, histology and proximal location were independently associated with PCC and may be important to identify patients at higher risk for post-polypectomy PCC.

Journal article

Cross A, Robbins E, Pack K, Stenson I, Patel B, Rutter M, Veitch A, Saunders B, Duffy S, Wooldrage Ket al., 2021, Colorectal cancer risk following polypectomy in a multicentre, retrospective, cohort study: an evaluation of the 2020 UK post-polypectomy surveillance guidelines, Gut, Vol: 70, Pages: 2307-2320, ISSN: 0017-5749

Objective:Colonoscopy surveillance aims to reduce colorectal cancer (CRC) incidence post-polypectomy. The 2020 UK guidelines recommend surveillance at three years for ‘high-risk’ patients with ≥2 premalignant polyps (PMPs) of which ≥1 is ‘advanced’ (serrated polyp [or adenoma] ≥10mm or with [high-grade] dysplasia); ≥5 PMPs; or ≥1 non-pedunculated polyp ≥20mm; ‘low-risk’ patients without these findings are instead encouraged to participate in population-based CRC screening. We examined the appropriateness of these risk classification criteria and recommendations.Design:Retrospective analysis of patients who underwent colonoscopy and polypectomy mostly between 2000–2010 at 17 UK hospitals, followed-up through 2017. We examined CRC incidence by baseline characteristics, risk group, and number of surveillance visits using Cox regression, and compared incidence with that in the general population using standardised incidence ratios (SIRs).Results:Among 21,318 patients, 368 CRCs occurred during follow-up (median: 10.1 years). Baseline CRC risk factors included age ≥55 years, ≥2 PMPs, adenomas with tubulovillous/villous/unknown histology or high-grade dysplasia, proximal polyps, and a baseline visit spanning 2–90 days. Compared with the general population, CRC incidence without surveillance was higher among those with adenomas with high-grade dysplasia (SIR:1.74, 95%CI:1.21–2.42) or ≥2 PMPs of which ≥1 was advanced (1.39, 1.09–1.75). For low-risk (71%) and high-risk (29%) patients, SIRs without surveillance were 0.75 (95%CI:0.63–0.88) and 1.30 (1.03–1.62), respectively; for high-risk patients after first surveillance, the SIR was 1.22 (0.91–1.60). Conclusion:These guidelines accurately classify post-polypectomy patients into those at high-risk, for whom one surveillance colonoscopy appears appropriate, and those at low-risk who can be managed by non-invasive screenin

Journal article

Cross AJ, Robbins EC, 2021, Reply, Clinical Gastroenterology and Hepatology, Vol: 19, Pages: 2217-2218, ISSN: 1542-3565

Journal article

Robbins EC, Cross AJ, 2021, Guaiac fecal occult blood tests and mortality: a 30-year follow-up of two pooled trials, Clinical Gastroenterology and Hepatology, Vol: 19, Pages: 892-894, ISSN: 1542-3565

Journal article

Robbins E, Wooldrage K, Stenson I, Pack K, Duffy S, Conell C, Wright S, Nickerson C, Martin J, Cross Aet al., 2020, Heterogeneity in colorectal cancer incidence among people recommended three-yearly surveillance post-polypectomy: a validation study, Endoscopy, Vol: 53, Pages: 402-410, ISSN: 0013-726X

BackgroundColonoscopy surveillance is recommended for patients at increased risk of colorectal cancer (CRC) following adenoma removal. Low-, intermediate-, and high-risk groups are defined by baseline adenoma characteristics. We previously evaluated surveillance in intermediate-risk patients using UK hospital data, identifying a higher-risk subgroup who benefitted from surveillance and a lower-risk subgroup who may not require surveillance. Here we explored whether these findings apply in individuals undergoing CRC screening. MethodsRetrospective study using data from the UK Flexible Sigmoidoscopy Screening Trial (UKFSST), English CRC screening pilot (ECP), and US Kaiser Permanente CRC prevention programme (KPCP). Screening participants aged 50–74 years and classed as intermediate-risk at baseline colonoscopy were included. CRC data were available through 2006 (KPCP) or 2014 (UKFSST, ECP). We classified participants into lower- and higher-risk subgroups using our previously identified baseline risk factors; higher-risk participants were those with incomplete colonoscopies, poor bowel preparation, adenomas ≥20mm or with high-grade dysplasia, or proximal polyps. We compared CRC incidence rates in these subgroups and in the presence versus absence of surveillance using Cox regression.ResultsOf 2291 intermediate-risk participants, 45% were classified as higher-risk. Median follow-up was 11.8 years. CRC incidence rates were significantly higher in the higher-risk than lower-risk subgroup (hazard ratio [HR]=2.08, 95%CI 1.07–4.06). Surveillance reduced CRC incidence rates in higher-risk participants (HR=0.35, 0.14–0.86), but not statistically significantly so in lower-risk participants (HR=0.41, 0.12–1.38).ConclusionAs previously demonstrated for hospital patients, screening participants classed as intermediate-risk comprise two risk subgroups. Surveillance clearly benefits the higher-risk subgroup.

Journal article

Cross A, Robbins E, Pack K, Stenson I, Kirby P, Patel B, Rutter MD, Veitch AM, Saunders B, Duffy SW, Wooldrage Ket al., 2020, Long-term colorectal cancer incidence after adenoma removal and the effects of surveillance on incidence: a multicentre, retrospective, cohort study, Gut, Vol: 69, Pages: 1645-1658, ISSN: 0017-5749

Objective Post-polypectomy colonoscopy surveillance aims to prevent colorectal cancer (CRC). The 2002 UK surveillance guidelines define low-, intermediate-, and high-risk groups, recommending different strategies for each. Evidence supporting the guidelines is limited. We examined CRC incidence and effects of surveillance on incidence among each risk group. Design Retrospective study of 33,011 patients who underwent colonoscopy with adenoma removal at 17 UK hospitals, mostly (87%) from 2000–2010. Patients were followed-up through 2016. Cox regression with time-varying covariates was used to estimate effects of surveillance on CRC incidence adjusted for patient, procedural, and polyp characteristics. Standardised incidence ratios (SIRs) compared incidence with that in the general population. Results After exclusions, 28,972 patients were available for analysis; 14,401 (50%) were classed as low-risk, 11,852 (41%) as intermediate-risk, and 2719 (9%) as high-risk. Median follow-up was 9.3 13years. In the low-, intermediate-, and high-risk groups, CRC incidence per 100,000 person-years was 14140 (95%CI 122–162), 221 (195–251), and 366 (295–453), respectively. CRC incidence was 40–50% lower with a single surveillance visit than with none: hazard ratios were 0.56 (0.39–0.80), 0.59 (0.43–0.81), and 0.49 (0.29–0.82) in the low-, intermediate-, and high-risk groups, respectively. Compared with the general population, CRC incidence without surveillance was similar among low-risk (SIR 0.86, 0.73–1.02) and intermediate-risk (1.16, 0.97–1.37) patients, but higher among high-risk patients (1.91, 1.39–2.56).20Conclusion Post-polypectomy surveillance reduces CRC risk. However, even without surveillance, CRC risk in some low-risk and intermediate-risk patients is no higher than in the general population. These patients could be managed by screening rather than surveillance.

Journal article

Robbins EC, Wooldrage K, Cross AJ, 2020, Is surveillance colonoscopy necessary for all patients with bowel polyps?, BMJ, Vol: 369, Pages: 1-5, ISSN: 1759-2151

Journal article

Cross A, Wooldrage K, Robbins E, Kralj-Hans I, MacRae E, Piggott C, Stenson I, Prendergast A, Patel B, Pack K, Howe R, Swart N, Snowball J, Duffy SW, Morris S, von Wagner C, Halloran S, Atkin Wet al., 2019, Faecal immunochemical tests (FIT) versus colonoscopy for surveillance after screening and polypectomy: a diagnostic accuracy and cost-effectiveness study, Gut, Vol: 68, Pages: 1642-1652, ISSN: 0017-5749

Objective The English Bowel Cancer Screening Programme (BCSP) recommends 3 yearly colonoscopy surveillance for patients at intermediate risk of colorectal cancer (CRC) postpolypectomy (those with three to four small adenomas or one ≥10 mm). We investigated whether faecal immunochemical tests (FITs) could reduce surveillance burden on patients and endoscopy services.Design Intermediate-risk patients (60–72 years) recommended 3 yearly surveillance were recruited within the BCSP (January 2012–December 2013). FITs were offered at 1, 2 and 3 years postpolypectomy. Invitees consenting and returning a year 1 FIT were included. Participants testing positive (haemoglobin ≥40 µg/g) at years one or two were offered colonoscopy early; all others were offered colonoscopy at 3 years. Diagnostic accuracy for CRC and advanced adenomas (AAs) was estimated considering multiple tests and thresholds. We calculated incremental costs per additional AA and CRC detected by colonoscopy versus FIT surveillance.Results 74% (5938/8009) of invitees were included in our study having participated at year 1. Of these, 97% returned FITs at years 2 and 3. Three-year cumulative positivity was 13% at the 40 µg/g haemoglobin threshold and 29% at 10 µg/g. 29 participants were diagnosed with CRC and 446 with AAs. Three-year programme sensitivities for CRC and AAs were, respectively, 59% and 33% at 40 µg/g, and 72% and 57% at 10 µg/g. Incremental costs per additional AA and CRC detected by colonoscopy versus FIT (40 µg/g) surveillance were £7354 and £180 778, respectively.Conclusions Replacing 3 yearly colonoscopy surveillance in intermediate-risk patients with annual FIT could reduce colonoscopies by 71%, significantly cut costs but could miss 30%–40% of CRCs and 40%–70% of AAs.

Journal article

Cross A, Wooldrage K, Robbins E, Pack K, Brown JP, Hamilton W, Thompson MR, Flashman KG, Halligan S, Thomas-Gibson S, Vance M, Saunders BP, Atkin Wet al., 2019, Whole colon investigation versus flexible sigmoidoscopy for suspected colorectal cancer based on presenting symptoms and signs: a multicentre cohort study, British Journal of Cancer, Vol: 120, Pages: 154-164, ISSN: 0007-0920

BackgroundPatients with suspected colorectal cancer (CRC) usually undergo colonoscopy. Flexible sigmoidoscopy (FS) may be preferred if proximal cancer risk is low. We investigated which patients could undergo FS alone.MethodsCohort study of 7375 patients (≥55 years) referred with suspected CRC to 21 English hospitals (2004–2007), followed using hospital records and cancer registries. We calculated yields and number of needed whole-colon examinations (NNE) to diagnose one cancer by symptoms/signs and subsite. We considered narrow (haemoglobin <11 g/dL men; <10 g/dL women) and broad (<13 g/dL men; <12 g/dL women) anaemia definitions and iron-deficiency anaemia (IDA).ResultsOne hundred and twenty-seven proximal and 429 distal CRCs were diagnosed. A broad anaemia definition identified 80% of proximal cancers; a narrow definition with IDA identified 39%. In patients with broad definition anaemia and/or abdominal mass, proximal cancer yield and NNE were 4.8% (97/2022) and 21. In patients without broad definition anaemia and/or abdominal mass, with rectal bleeding or increased stool frequency (41% of cohort), proximal cancer yield and NNE were 0.4% (13/3031) and 234.ConclusionMost proximal cancers are accompanied by broad definition anaemia. In patients without broad definition anaemia and/or abdominal mass, with rectal bleeding or increased stool frequency, proximal cancer is rare and FS should suffice.

Journal article

Robbins E, Wooldrage K, MacRae E, Stenson I, Patel B, Pack K, Piggott C, Pearson S, Snowball J, Duffy S, Halloran S, Atkin W, Cross Aet al., 2018, OTU-029 Faecal immunochemical tests (FIT) for surveillance after screening and polypectomy: an accuracy and efficiency study, British Society of Gastroenterology Annual Conference, Publisher: BMJ Publishing Group, Pages: A222-A222, ISSN: 0017-5749

Conference paper

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