Colonoscopy by nurse endoscopists: the right answer for the growing demand for colonoscopy in clinical practice?

In their recent study, van Putten and colleagues reported the Dutch experience of nurse endoscopists in performing colonoscopies. They reported that adherence to international standards and patient satisfaction were very high, and most of the patients had no specific preference for a physician or a nurse endoscopist [1]. Although I find this report interesting, I cannot entirely share its conclusions, and feel that some comment is needed.

I agree that the growing demand for colonoscopies in clinical practice needs clear answers, but I am not sure that nurse endoscopists are the right answer. Van Putten et al. state correctly that the numbers of nurse endoscopists are now increasing in some Western countries, especially in the United Kingdom [2]. In Italy, as well as in other Mediterranean countries, the law does not permit nurses to perform instrumental diagnosis, only physicians. I feel that this approach is right, because instrumental diagnosis is a medical act that should be the preserve of physicians.

From a medicolegal point of view, who is responsible for endoscopic complications? Van Putten et al. report a 0.2 % complication rate in their populations screened by nurse endoscopists, one of the complications occurring after polypectomy [1]. Who takes the responsibility for such complications, the physician or the nurse? Moreover, who cover the costs of these complications? The national health system or the insurance of the hospital in which the complication occurred? In light of these considerations, in Italy at least this approach is not feasible.

So, another way to approach the growing demand for colonoscopy is better selection of the patients undergoing colonoscopy. For example, a combination of noninvasive tests may be useful in selecting patients for colonoscopy. We know that the immunochemical fecal occult blood test (FOBT) seems to be more sensitive than the guaiac FOBT test for colorectal cancer (CRC) screening [3], whilst fecal calprotectin alone does not seem able to differentiate between CRC and other colonic inflammatory disorders [4]. However, combined S100A12, hemoglobin-haptoglobin, and tissue inhibitor of metalloproteinase-1 (TIMP-1) testing produced a high sensitivity of 82 %, with the highest increase of sensitivity found at early tumor stages [5]. Thus, a marker pair, S100A12 and hemoglobin-haptoglobin, or a triple combination also including TIMP-1, allowed CRC to be detected at significantly higher rates than can be obtained with the FOBT alone [5]. This promising approach has been confirmed by a recent Italian study, which tested a combination of fecal tests (immunochemical FOBT, tumor enzyme M2-PK, fecal calprotectin) as markers for advanced neoplasia in a selected series of patients requiring colonoscopy for the suspicion of CRC. The study showed that the best combination of tests to predict the risk of CRC in this series was FOBT plus M2-PK, as the risk of cancer was as high as 79 % in patients showing positivity to both markers [6]. This approach may therefore be a sensitive tool in clinical practice for appropriate management of colonoscopy waiting lists, as it allows patients to be classified into different degrees of priority for investigation, according to their foreseeable risk of CRC.

Finally, a promising tool in CRC screening seems to be breath analysis. Altomare and colleagues found recently that patients with CRC have a specific pattern of volatile organic compounds (VOC) compared with the healthy population, with an accuracy of over 75 % [7].

In light of these considerations, in my opinion the growing demand for colonoscopies in clinical practice needs to be addressed by improving the appropriateness of colonoscopy (performing it only when suspicion of disease is high) by means of a combination of noninvasive tests, rather than creating a new professional role in the endoscopic landscape.

• References

• 1 van Putten PG, Ter Borg F, Adang RP et al. Nurse endoscopists perform colonoscopies according to the international standard and with high patient satisfaction. Endoscopy 2012; 44: 1127-1132
• 2 Douglass A, Barrison I, Powell A et al. The nurse endoscopist’s contribution to service delivery. Gastrointest Nurs 2004; 2: 21-24
• 3 Fraser CG, Matthew CM, Mowat NA et al. Immunochemical testing of individuals positive for guaiac faecal occult blood test in a screening programme for colorectal cancer: an observational study. Lancet Oncol 2006; 7: 127-131
• 4 von Roon AC, Karamountzos L, Purkayastha S et al. Diagnostic precision of fecal calprotectin for inflammatory bowel disease and colorectal malignancy. Am J Gastroenterol 2007; 102: 803-813
• 5 Karl J, Wild N, Tacke M et al. Improved diagnosis of colorectal cancer using a combination of fecal occult blood and novel fecal protein markers. Clin Gastroenterol Hepatol 2008; 6: 1122-1128
• 6 Parente F, Marino B, Ilardo A et al. A combination of faecal tests for the detection of colon cancer: a new strategy for an appropriate selection of referrals to colonoscopy? A prospective multicentre Italian study. Eur J Gastroenterol Hepatol 2012; 24: 1145-1152
• 7 Altomare DF, Di Lena M, Porcelli F et al. Exhaled volatile organic compounds identify patients with colorectal cancer. Br J Surg 2013; 100: 144-150