poorly differentiated invasive squamous cell cancer (Fig. 1). On EUS, CT, and positron emission tomography scans, the lesion was staged at T1b N0 M0. The patient received chemo- radiation therapy (weekly paclitaxel and carboplatin for 5 weeks; 5000 cGy in 25 fractions). Follow-up endoscopy with biopsy showed no evidence of residual cancer. As far as we know, this is the first case report where a patient with Barrett’s epithelium with adenocarinoma in situ achieved a complete response with ablative therapy and then went on to develop invasive squamous cell cancer in the neosquamous epithelium at the original site of the Barrett’s epithelium. This case again underscores the importance of regular follow-up and an additional con- cern about the stability of the neosquamous mucosa. Kulwinder S. Dua, MD Joseph Merrill, MD Department of Medicine, Division of Gastroenterology and Hepatology Richard Komorowski, MD Department of Pathology Medical College of Wisconsin, Milwaukee, Wisconsin, USA REFERENCES 1. Overholt BF, Panjehpour M, Halberg DL. Photodynamic therapy for Bar- rett’s esophagus with dysplasia and/or early stage carcinoma: long-term results. Gastrointest Endosc 2003;58:183-8. 2. Shaheen NJ, Greenwald BD, Peery AF, et al. Safety and efficacy of endo- scopic spray cryotherapy for Barrett’s esophagus with high-grade dyspla- sia. Gastrointest Endosc 2010;71:680-5. 3. Shaheen NJ, Overholt BF, Sampliner RE, et al. Durability of radiofrequency ablation in Barrett’s esophagus with dysplasia. Gastroenterology 2011; 141:460-8. 4. Shaheen NJ, Sharma P, Overholt BF, et al. Radiofrequency ablation in Barrett’s esophagus with dysplasia. N Engl J Med 2009;360:2277-88. 5. Gray NA, Odze RD, Spechler SJ. Buried metaplasia after endoscopic abla- tion of Barrett’s esophagus: a systematic review. Am J Gastroenterol 2011;106:1899-908; quiz 1909. 6. Pouw RE, Gondrie JJ, Rygiel AM, et al. Properties of the neosquamous epithelium after radiofrequency ablation of Barrett’s esophagus contain- ing neoplasia. Am J Gastroenterol 2009;104:1366-73. 7. Odze RD, Lauwers GY. Histopathology of Barrett’s esophagus after abla- tion and endoscopic mucosal resection therapy. Endoscopy 2008;40: 1008-15. 8. Dua KS, Merrill JT, Komorowski R. Neosquamous epithelium after Bar- rett’s ablation: cause for concern? Gastrointest Endosc 2011;74:1424-5. http://dx.doi.org/10.1016/j.gie.2012.07.008 Poor preps and piano tuners: Fermi’s approach to quantifying the risk for interval colon cancer To the Editor: Recent studies have suggested that poor bowel prep- aration results in missed adenomas during colono- scopy. 1-4 This has prompted experts to recommend early repeat colonoscopy in patients with poor prepa- rations, based on the notion that missed adenomas put patients at an increased risk for interval cancers. 4-5 We wondered about the magnitude of such risk and when the next colonoscopy should be scheduled after a sub- optimal colonoscopy. The risk for cancer after a suboptimal colonoscopy depends on the probability of missing a polyp that will turn cancerous before the next colonoscopy. This proba- bility increases with the number and size of polyps seen during the initial colonoscopy. 6 The less colon visualized because of poor preparation, the higher the likelihood of missed polyps. A long interval until the next colonoscopy also will increase the probability of the missed polyp becoming cancerous. Unfortunately, there are insufficient data to establish exact mathematical relationships between the probability of cancer and its dependence on polyp number, size, interval length, and quality of preparation at the index colonoscopy. Figure 1. Moderately to poorly differentiated invasive squamous cell cancer. Letters to the Editor www.giejournal.org Volume 76, No. 5 : 2012 GASTROINTESTINAL ENDOSCOPY 1083