Letter to the editor
Response: Our cost-effectiveness model on endoscopic surveillance for nondysplastic Barrett’s esophagus involved over 50 model inputs for the estimation of costs and effects. The estimates chosen were complied from those in the scientific literature combined with extensive clinical knowledge and input by coauthors D.I.W., G.M., and T.B., who have run a very large Barrett’s surveillance program with follow-up across a decade. Dr Ganz has argued that our choice of 1 of the model inputs, “progression of nondysplasia to cancer” (0.33%/year) in the non-surveillance arm, is underestimated for the reasons he presents. We justified the use of this estimate in terms of using data from a meta-analysis by Desai et al1 on a subset of higher-quality studies with more than 5 years of follow-up, confirmed by similar rates observed in large observational studies2-4 and our own outcome data. We acknowledge that the true rate remains to some extent uncertain, but we consider the estimate to be representative of a consensus from the published literature. Although it is clear that models are only as good as the data on which they are based, and we encourage critique on any issue of our economic model, we remind Dr Ganz that we have not just used “the 0.33%/year value alone.” Indeed, because of the complexity and uncertainty inherent in the “progression to cancer” estimate, we re-ran the model using a wide range of progression estimates (ie, 0.09%/year to 0.5%/year). We are confident that this range is sufficiently wide to capture the range of circumstances, cohorts, assumptions, and biases reported in the literature. We are not aware of any highquality prospective data that suggest this progression rate falls outside the range of values we have tested in our model. More importantly, the key conclusion drawn from our analyses is surveillance may not be cost-effective with different cancer progression rates from nondysplastic Barrett’s esophagus. Our conclusions remain robust even when we fit models with progression rates beyond the currently accepted credible limit for nondysplastic Barrett’s (O1%), although we concede that the results are more volatile at these rates. Our model provides a useful validation to the growing body of work that appropriately seeks to identify high-risk individuals to prioritize for surveillance. As statistician George Box famously said, “Essentially, all models are wrong, some are useful.” Louisa G. Gordon, PhD Centre for Applied Health Economics Griffith Health Institute Griffith University Queensland, Australia
www.giejournal.org
George C. Mayne, PhD Timothy Bright, PhD, MBBS Flinders University Department of Surgery Flinders Medical Centre South Australia, Australia David C. Whiteman, PhD, MBBS QIMR Berghofer Medical Research Institute Population Health Department Royal Brisbane Hospital Brisbane, Queensland, Australia David I. Watson, MD, MBBS Flinders University Department of Surgery Flinders Medical Centre South Australia, Australia
REFERENCES 1. Desai TK, Krishnan K, Samala N, et al. The incidence of oesophageal adenocarcinoma in non-dysplastic Barrett’s oesophagus: a meta-analysis. Gut 2012;61:970-6. 2. Bhat S, Coleman HG, Yousef F, et al. Risk of malignant progression in Barrett’s esophagus patients: results from a large population-based study. J Natl Cancer Inst 2011;103:1049-57. 3. de Jonge PJ, van Blankenstein M, Looman CW, et al. Risk of malignant progression in patients with Barrett’s oesophagus: a Dutch nationwide cohort study. Gut 2010;59:1030-6. 4. Hvid-Jensen F, Pedersen L, Drewes AM, et al. Incidence of adenocarcinoma among patients with Barrett’s esophagus. N Engl J Med 2011;365:1375-83. http://dx.doi.org/10.1016/j.gie.2014.02.020
Wireless endoscopy capsules should not be released in the environment To the Editor: I’ve read with interest the technology status evaluation report on wireless capsule endoscopy (WCE) recently published in this journal.1 Since its introduction in clinical practice, WCE has gained popularity among gastroenterologists, and its use and indications have increased. A systematic review2 published in 2010 has analyzed 227 articles, involving 22,840 capsule procedures; this number is certainly far from the real number of WCE procedures performed worldwide in recent years because the majority of cases are not published. Nonetheless, these data can give an idea of the great number of WCE capsules used every year. As stated in the evaluation report, the capsule “is disposable and designed to be excreted.” Therefore, the capsules are generally released into toilet sewers. However, the WCE system is a complex device that includes 2 batteries, a metal oxide semiconductor, and a diode illumination source. Many of these components, especially the chemicals in the batteries, can produce potential hazards and
Volume 80, No. 1 : 2014 GASTROINTESTINAL ENDOSCOPY 191
Letter to the editor
contaminate the environment when the capsules are improperly disposed of. Now that use of the capsules is widespread, I think it is time to start suggesting that patients collect the capsules after their use. These capsules should be treated as special waste to avoid contamination of waterstreams and grounds. This policy should be used for both outpatients and inpatients. As an alternative, recycling of disposable WCE capsules for other purposes could also be considered, as we reported in a preliminary study.3 I hope that the scientific society and the American Society for Gastrointestinal Endoscopy will take this aspect into account in the next technology status evaluation report.
DISCLOSURE The following author disclosed a financial relationship relevant to this publication: A. Pezzoli is a consultant for SEDA spa. Alessandro Pezzoli, MD Department of Gastroenterology and Endoscopy Unit Sant’Anna Hospital Ferrara, Italy
REFERENCES 1. ASGE Technology Committee, Wang A, Banerjee S, et al. Wireless capsule endoscopy. Gastrointest Endosc 2013;78:805-15. 2. Liao Z, Gao R, Xu C, et al. Indications and detection, completion, and retention rates of small-bowel capsule endoscopy: a systematic review. Gastrointest Endosc 2010;71:280-6. 3. Pezzoli A, Ricci N, Fusetti N, et al. Reactivation of used endoscopic capsules. Dig Liver Dis 2011;43(Suppl 3):S160. http://dx.doi.org/10.1016/j.gie.2014.02.021
Response:
At this time, there appear to be few to no data regarding the environmental impact of used capsule endoscopes, and that could be a good area for research, especially from the manufacturers of these widely used disposable devices. Questions that need to be answered include these: (1) What is the risk of capsule dissolution while it is in the sewage system? (2) What is the impact on groundwater and the surrounding environment in a landfill from the components of a capsule endoscope should it dissolve? (3) What is a good method for patients to collect these used capsules, should it become apparent that this is something that should be done to avoid an adverse impact on the environment? Finally, future research could identify new capsule designs that are partially or completely biodegradable. We applaud this type of concern from our medical colleagues around the world, and it emphasizes how important it is that the journal has a global readership. We all share the same home; let’s make sure we take care of it. Sarah A. Rodriguez, MD Oregon Health and Science University Department of Gastroenterology The Oregon Clinic Portland, Oregon, USA REFERENCE 1. Wang A, Barth B, Banerjee S, et al; and the ASGE Technology Assessment Committee. Wireless capsule endoscopy. Gastrointest Endosc 2013;78:805-13. http://dx.doi.org/10.1016/j.gie.2014.03.033
Esophageal luminal restoration for a patient with a long lye-induced stricture via tunnel endoscopic therapy during a rendezvous procedure followed by self-dilation (with video) To the Editor:
We thank Dr Pezzoli for his interest in our technical review of capsule endoscopy.1 He brings up an excellent point that has not been addressed in the medical literature, namely, the potential environmental impact of the common practice of flushing used capsule endoscopes into the sewer system. Informal calls to one of the manufacturers of the endoscopes revealed that there are no data from the manufacturer’s standpoint on this topic. What happens to solid inorganic particulate matter that is flushed into the sewer system? Locally in Oregon, at least, it is filtered out during processing of the sewage and ultimately is taken to a landfill. The Department of Environmental Quality here did not express any particular concern regarding silver oxide or lithium battery components being disposed of with the regular trash, although it must be emphasized that this was not a formal assessment.
A 54-year-old man presented with pharyngeal damage and a complete esophageal obstruction 6 months after lye ingestion. He was dependent on gastrostomy feeding and had to continuously collect his oral secretions. Caustic injuries to the pharynx and esophagus are complex to manage. Surgical management can include esophagectomy and myocutaneous flaps, is complex, and carries significant morbidity and mortality.1 Traditional endoscopic rendezvous procedures require transillumination to guide stricture dissection.2 This has limited rendezvous procedures to obstructions less than 2.5 cm in length. Submucosal tunneling has been previously used to dissect a 4.5-cm stricture.3 Restenosis of these strictures often occurs because of lack of re-epithelialization. This leads to a need for repeated endoscopic procedures. Self-dilation has been successfully used to manage resistant esophageal strictures.4
192 GASTROINTESTINAL ENDOSCOPY Volume 80, No. 1 : 2014
www.giejournal.org
Response: Our cost-effectiveness model on endoscopic surveillance for nondysplastic Barrett’s esophagus involved over 50 model inputs for the estimation of costs and effects. The estimates chosen were complied from those in the scientific literature combined with extensive clinical knowledge and input by coauthors D.I.W., G.M., and T.B., who have run a very large Barrett’s surveillance program with follow-up across a decade. Dr Ganz has argued that our choice of 1 of the model inputs, “progression of nondysplasia to cancer” (0.33%/year) in the non-surveillance arm, is underestimated for the reasons he presents. We justified the use of this estimate in terms of using data from a meta-analysis by Desai et al1 on a subset of higher-quality studies with more than 5 years of follow-up, confirmed by similar rates observed in large observational studies2-4 and our own outcome data. We acknowledge that the true rate remains to some extent uncertain, but we consider the estimate to be representative of a consensus from the published literature. Although it is clear that models are only as good as the data on which they are based, and we encourage critique on any issue of our economic model, we remind Dr Ganz that we have not just used “the 0.33%/year value alone.” Indeed, because of the complexity and uncertainty inherent in the “progression to cancer” estimate, we re-ran the model using a wide range of progression estimates (ie, 0.09%/year to 0.5%/year). We are confident that this range is sufficiently wide to capture the range of circumstances, cohorts, assumptions, and biases reported in the literature. We are not aware of any highquality prospective data that suggest this progression rate falls outside the range of values we have tested in our model. More importantly, the key conclusion drawn from our analyses is surveillance may not be cost-effective with different cancer progression rates from nondysplastic Barrett’s esophagus. Our conclusions remain robust even when we fit models with progression rates beyond the currently accepted credible limit for nondysplastic Barrett’s (O1%), although we concede that the results are more volatile at these rates. Our model provides a useful validation to the growing body of work that appropriately seeks to identify high-risk individuals to prioritize for surveillance. As statistician George Box famously said, “Essentially, all models are wrong, some are useful.” Louisa G. Gordon, PhD Centre for Applied Health Economics Griffith Health Institute Griffith University Queensland, Australia
www.giejournal.org
George C. Mayne, PhD Timothy Bright, PhD, MBBS Flinders University Department of Surgery Flinders Medical Centre South Australia, Australia David C. Whiteman, PhD, MBBS QIMR Berghofer Medical Research Institute Population Health Department Royal Brisbane Hospital Brisbane, Queensland, Australia David I. Watson, MD, MBBS Flinders University Department of Surgery Flinders Medical Centre South Australia, Australia
REFERENCES 1. Desai TK, Krishnan K, Samala N, et al. The incidence of oesophageal adenocarcinoma in non-dysplastic Barrett’s oesophagus: a meta-analysis. Gut 2012;61:970-6. 2. Bhat S, Coleman HG, Yousef F, et al. Risk of malignant progression in Barrett’s esophagus patients: results from a large population-based study. J Natl Cancer Inst 2011;103:1049-57. 3. de Jonge PJ, van Blankenstein M, Looman CW, et al. Risk of malignant progression in patients with Barrett’s oesophagus: a Dutch nationwide cohort study. Gut 2010;59:1030-6. 4. Hvid-Jensen F, Pedersen L, Drewes AM, et al. Incidence of adenocarcinoma among patients with Barrett’s esophagus. N Engl J Med 2011;365:1375-83. http://dx.doi.org/10.1016/j.gie.2014.02.020
Wireless endoscopy capsules should not be released in the environment To the Editor: I’ve read with interest the technology status evaluation report on wireless capsule endoscopy (WCE) recently published in this journal.1 Since its introduction in clinical practice, WCE has gained popularity among gastroenterologists, and its use and indications have increased. A systematic review2 published in 2010 has analyzed 227 articles, involving 22,840 capsule procedures; this number is certainly far from the real number of WCE procedures performed worldwide in recent years because the majority of cases are not published. Nonetheless, these data can give an idea of the great number of WCE capsules used every year. As stated in the evaluation report, the capsule “is disposable and designed to be excreted.” Therefore, the capsules are generally released into toilet sewers. However, the WCE system is a complex device that includes 2 batteries, a metal oxide semiconductor, and a diode illumination source. Many of these components, especially the chemicals in the batteries, can produce potential hazards and
Volume 80, No. 1 : 2014 GASTROINTESTINAL ENDOSCOPY 191
Letter to the editor
contaminate the environment when the capsules are improperly disposed of. Now that use of the capsules is widespread, I think it is time to start suggesting that patients collect the capsules after their use. These capsules should be treated as special waste to avoid contamination of waterstreams and grounds. This policy should be used for both outpatients and inpatients. As an alternative, recycling of disposable WCE capsules for other purposes could also be considered, as we reported in a preliminary study.3 I hope that the scientific society and the American Society for Gastrointestinal Endoscopy will take this aspect into account in the next technology status evaluation report.
DISCLOSURE The following author disclosed a financial relationship relevant to this publication: A. Pezzoli is a consultant for SEDA spa. Alessandro Pezzoli, MD Department of Gastroenterology and Endoscopy Unit Sant’Anna Hospital Ferrara, Italy
REFERENCES 1. ASGE Technology Committee, Wang A, Banerjee S, et al. Wireless capsule endoscopy. Gastrointest Endosc 2013;78:805-15. 2. Liao Z, Gao R, Xu C, et al. Indications and detection, completion, and retention rates of small-bowel capsule endoscopy: a systematic review. Gastrointest Endosc 2010;71:280-6. 3. Pezzoli A, Ricci N, Fusetti N, et al. Reactivation of used endoscopic capsules. Dig Liver Dis 2011;43(Suppl 3):S160. http://dx.doi.org/10.1016/j.gie.2014.02.021
Response:
At this time, there appear to be few to no data regarding the environmental impact of used capsule endoscopes, and that could be a good area for research, especially from the manufacturers of these widely used disposable devices. Questions that need to be answered include these: (1) What is the risk of capsule dissolution while it is in the sewage system? (2) What is the impact on groundwater and the surrounding environment in a landfill from the components of a capsule endoscope should it dissolve? (3) What is a good method for patients to collect these used capsules, should it become apparent that this is something that should be done to avoid an adverse impact on the environment? Finally, future research could identify new capsule designs that are partially or completely biodegradable. We applaud this type of concern from our medical colleagues around the world, and it emphasizes how important it is that the journal has a global readership. We all share the same home; let’s make sure we take care of it. Sarah A. Rodriguez, MD Oregon Health and Science University Department of Gastroenterology The Oregon Clinic Portland, Oregon, USA REFERENCE 1. Wang A, Barth B, Banerjee S, et al; and the ASGE Technology Assessment Committee. Wireless capsule endoscopy. Gastrointest Endosc 2013;78:805-13. http://dx.doi.org/10.1016/j.gie.2014.03.033
Esophageal luminal restoration for a patient with a long lye-induced stricture via tunnel endoscopic therapy during a rendezvous procedure followed by self-dilation (with video) To the Editor:
We thank Dr Pezzoli for his interest in our technical review of capsule endoscopy.1 He brings up an excellent point that has not been addressed in the medical literature, namely, the potential environmental impact of the common practice of flushing used capsule endoscopes into the sewer system. Informal calls to one of the manufacturers of the endoscopes revealed that there are no data from the manufacturer’s standpoint on this topic. What happens to solid inorganic particulate matter that is flushed into the sewer system? Locally in Oregon, at least, it is filtered out during processing of the sewage and ultimately is taken to a landfill. The Department of Environmental Quality here did not express any particular concern regarding silver oxide or lithium battery components being disposed of with the regular trash, although it must be emphasized that this was not a formal assessment.
A 54-year-old man presented with pharyngeal damage and a complete esophageal obstruction 6 months after lye ingestion. He was dependent on gastrostomy feeding and had to continuously collect his oral secretions. Caustic injuries to the pharynx and esophagus are complex to manage. Surgical management can include esophagectomy and myocutaneous flaps, is complex, and carries significant morbidity and mortality.1 Traditional endoscopic rendezvous procedures require transillumination to guide stricture dissection.2 This has limited rendezvous procedures to obstructions less than 2.5 cm in length. Submucosal tunneling has been previously used to dissect a 4.5-cm stricture.3 Restenosis of these strictures often occurs because of lack of re-epithelialization. This leads to a need for repeated endoscopic procedures. Self-dilation has been successfully used to manage resistant esophageal strictures.4
192 GASTROINTESTINAL ENDOSCOPY Volume 80, No. 1 : 2014
www.giejournal.org
