Cost‐effectiveness of colorectal cancer screening with computed tomography colonography

Abstract

Endogenous acetylcholine is an important modulator of sensory processing, especially at the spinal level, where nociceptive (pain‐related) stimuli enter the central nervous system and are integrated before being relayed to the brain. To decipher the organization of the local cholinergic circuitry in the spinal dorsal horn, we used transgenic mice expressing enchanced green fluorescent protein specifically in cholinergic neurons (ChAT::EGFP) and characterized the morphology, neurochemistry, and firing properties of the sparse population of cholinergic interneurons in this area. Three‐dimensional reconstruction of lamina III ChAT::EGFP neurons based either on their intrinsic fluorescence or on intracellular labeling in live tissue demonstrated that these neurons have long and thin processes that grow preferentially in the dorsal direction. Their dendrites and axon are highly elongated in the rostrocaudal direction, beyond the limits of a single spinal segment. These unique morphological features suggest that dorsal horn cholinergic interneurons are the main contributors to the plexus of cholinergic processes located in lamina IIi, just dorsal to their cell bodies. In addition, immunostainings demonstrated that dorsal horn cholinergic interneurons in the mouse are γ‐aminobutyric acidergic and express nitric oxide synthase, as in rats. Finally, electrophysiological recordings from these neurons in spinal cord slices demonstrate that two‐thirds of them have a repetitive spiking pattern with frequent rebound spikes following hyperpolarization. Altogether our results indicate that, although they are rare, the morphological and functional features of cholinergic neurons enable them to collect segmental information in superficial layers of the dorsal horn and to modulate it over several segments. J. Comp. Neurol. 519:3139–3158, 2011. © 2011 Wiley‐Liss, Inc.

Screening and Surveillance for the Early Detection of Colorectal Cancer and Adenomatous Polyps, 2008: A Joint Guideline from the American Cancer Society, the US Multi-Society Task Force on Colorectal Cancer, and the American College of Radiology

“…No CRC screening test is perfect, either for cancer detection or adenoma detection. Each test has unique advantages, each has been shown to be cost-effective, [205][206][207][208] and each has associated limitations and risks. Patient preferences and availability of resources play an important role in the selection of screening tests.…”

The Role of Computed Tomographic Colonography in Colorectal Cancer Screening

“…21 The only study that did not report CTC as less cost-effective than colonoscopy did not consider the cost of follow-up colonoscopies for polyps ≤ 5 mm, which will be required in 15-25% of patients. 22, 23 Heitman et al compared screening by CTC and screening by colonoscopy from a Canadian perspective. 25 They conducted a decision analysis to assess cost-effectiveness among averagerisk individuals greater than 50 years old.…”

CT colonography: does it satisfy the necessary criteria for a colorectal screening test?

“…Having said that, it stands to reason that primary CTC with selective polypectomy should be more cost-effective than primary colonoscopy if certain basic assumptions are met. One key assumption that is often missed is that polypectomy should be avoided for isolated diminutive lesions seen at CTC [15]. Diagnostic performance for CTC should reflect current practice and the input cost for CTC should be considerably less than colonoscopy.…”

“…Ideally, extracolonic assessment should be factored in as well [16]. In general, it is quite easy to demonstrate that CTC is cost-effective compared with no screening [14], but with realistic input assumptions it can also be shown to be much more cost-effective than endoscopic strategies [15,16]. Beyond the typical Markov modeling, other decision analyses have been applied to certain key aspects of CTC screening, such as the management of small (6-9 mm) polyps [17,18].…”