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Stool-Based Testing for Post-Polypectomy Colorectal Cancer Surveillance
TAKE-HOME MESSAGE
- This cross-sectional observational study investigated the impact of a stool-based surveillance strategy in patients undergoing post-polypectomy surveillance in Europe. The multitarget stool DNA (mt-sDNA) test (AUROC, 0.72) outperformed fecal immunochemical test (FIT) OC-Sensor (AUROC, 0.61; P < .01) and FIT FOB-Gold (AUROC, 0.59; P < .01) for detecting advanced neoplasia in a surveillance cohort (N = 3453). A subsequent model-based analysis showed that a stool-based surveillance strategy was as effective in reducing colorectal cancer–related mortality and resulted in a 15% to 41% decrease in the number of colonoscopies when compared with a colonoscopy-based strategy. FIT-based strategies resulted in cost savings, whereas mt-sDNA-based strategies were more costly than colonoscopy-based strategies. No reduction in the predicted number of colonoscopies was observed on sensitivity analysis evaluating surveillance according to US guidelines.
- These findings suggest that, in a Europe setting, a stool-based post-polypectomy surveillance strategy may be as effective as a colonoscopy-based strategy with the added benefit of reducing both the number of colonoscopies and costs. However, these benefits may not be seen in a US setting.
abstract
This abstract is available on the publisher's site.
Access this abstract now Full Text Available for ClinicalKey SubscribersBACKGROUND & AIMS
Colonoscopy-based surveillance to prevent colorectal cancer (CRC) causes substantial burden for patients and health care. Stool tests may help to reduce surveillance colonoscopies by limiting colonoscopies to individuals at increased risk of advanced neoplasia.
METHODS
This cross-sectional observational study included individuals aged 50-75 years with surveillance indication. Before bowel preparation, participants collected samples for a multitarget stool DNA test and 2 fecal immunochemical tests (FITs). Test accuracy was calculated for all surveillance indications. For the post-polypectomy indication only, which is the most common and is associated with a relatively low CRC risk, long-term impact of stool-based surveillance was evaluated with the Adenoma and Serrated Pathway to Colorectal Cancer model. Stool-based strategies were simulated to tune each test's positivity threshold to obtain strategies at least as effective as colonoscopy surveillance.
RESULTS
There were 3453 individuals with results for all stool tests and colonoscopy; 2226 had previous polypectomy, 1003 had previous CRC, and 224 had a familial risk. Areas under the receiver operating characteristic curve for advanced neoplasia were 0.72 (95% CI, 0.69-0.75) for the multitarget stool DNA test, 0.61 (95% CI, 0.58-0.64) for the FIT OC-SENSOR (Eiken Chemical Co, Tokyo, Japan) and 0.59 (95% CI, 0.56-0.61) for the FIT FOB-Gold (Sentinel, Milan, Italy). Stool-based post-polypectomy surveillance strategies at least as effective as colonoscopy surveillance reduced the number of colonoscopies by 15%-41% and required 5.6-9.5 stool tests over a person's lifetime. Multitarget stool DNA-based surveillance was more costly than colonoscopy surveillance, whereas FIT-based surveillance saved costs.
CONCLUSIONS
This study found that stool-based post-polypectomy surveillance strategies can be safe and cost-effective, with potential to reduce the number of colonoscopies by up to 41%.
CLINICALTRIALS
gov, Number: NCT02715141.
Additional Info
Stool-Based Testing for Post-Polypectomy Colorectal Cancer Surveillance Safely Reduces Colonoscopies: The Molecular Stool Testing for Colorectal Cancer Surveillance Study
Gastroenterology 2024 Aug 30;[EPub Ahead of Print], B Carvalho, W de Klaver, F van Wifferen, MCJ van Lanschot, AJP van Wetering, QEW van der Zander, M Lemmens, AS Bolijn, M Tijssen, PD Diemen, N Buekers, K Daenen, J van der Meer, PG van Mulligen, BS Hijmans, S de Ridder, L Meiqari, M Bierkens, RWM van der Hulst, JPH Kuyvenhoven, AM van Berkel, ACTM Depla, ME van Leerdam, JM Jansen, CA Wientjes, JA Straathof, ETP Keulen, D Ramsoekh, LMG Moons, M Zacherl, AAM Masclee, M de Wit, MJE Greuter, M van Engeland, E Dekker, VMH Coupé, GA MeijerFrom MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
As part of a larger European clinical study, 2226 patients undergoing colon polyp surveillance received three stool tests (multitarget stool DNA [mt-sDNA], fecal immunochemical test [FIT]-OC, and FIT FOB-Gold) and then had colonoscopy. The sensitivity for detection of advanced neoplasia (AN) was calculated and plugged into a model to estimate long-term effects on CRC mortality. The aim was to determine if a similar outcome (CRC mortality, life-years gained) could be accomplished with fewer colonoscopies if stool testing was used, and colonoscopy performed only for positive results on stool tests. The answer is yes — in Europe, with European Society for Gastrointestinal Endoscopy guidelines, which recommend surveillance only if patients have: 1) adenoma(s) larger than 1 cm; 2) adenoma with high-grade dysplasia; 3) five or more adenomas; or 4) advanced sessile serrated polyps based on size (not histology).
The sensitivity for AN was greater for mt-sDNA (59%) than for FIT (28%–32%), with a significantly better receiver operating curve. This was largely owing to better detection of advanced sessile serrated polyps. Then, the analysis “tuned” thresholds for the stool tests to achieve equivalent results with guideline-recommended colonoscopy surveillance. The numbers of colonoscopies could be reduced by 15%–41%, with annual FIT achieving the best result at the lowest cost. To achieve this result, the authors assumed that 92% of patients would complete a stool test, and 100% would have colonoscopy if the result of the stool test was abnormal. In real life, this does not occur. When more realistic completion rates (73%) were modeled, the benefit of the stool test disappeared. Moreover, when the authors applied the modeling to US surveillance recommendations, they did not observe an equivalent reduction in colonoscopies.
The concept of using noninvasive testing after polyp removal could reduce the burden of colonoscopy during surveillance. Whether mt-sDNA or FIT are the best noninvasive tests to use in higher-risk patients with prior ANs is debatable. The authors excluded very high–risk patients with prior CRC and family history from this analysis for this reason. Invalid tests were far more common for mt-sDNA (7.0%) than for FIT (0.7%–0.9%), and costs were higher with mt-sDNA. We must remember that these are simulated outcomes, and further study is needed to determine whether surveillance can be safely avoided in patients with AN at a baseline colonoscopy, if they are willing to complete stool testing.
This study also highlights an important feature of noninvasive stool testing. Adherence with stool test completion, and follow-up colonoscopy after an abnormal test result must be high for any such program to be effective — especially in patients with a past history of AN.
Finally, the authors make a statement that “currently, early detection of CRC is the most sensible approach for reducing the number of CRC-related deaths.” I would suggest that CRC prevention by detecting and removing ANs may be a more effective way to reduce CRC-related deaths in high-risk patients with prior ANs.