Colorectal cancer prevention in Brazil - where are we?

Coy, Cláudio Saddy Rodrigues

doi:10.1016/j.jcol.2013.09.001

Cited by 8 publications

(2 citation statements)

References 3 publications

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“…The American Cancer Society (ACS) (7) categorizes secondary screening methods into stool-based tests, which are less invasive, but require more frequent testing, and visual examinations of the colon and rectum. It is recommended to perform annual fecal immunochemical testing (FIT) and high-sensitivity guaiac-based fecal occult blood testing (gFOBT), or every 3 years, the multi-target stool DNA test (mt--sDNA) (Coy et al, 2014) (17) .…”

Section: Discussionmentioning

confidence: 99%

Analysis of the Tracking Initiatives of Colorectal Cancer in Brazil

TOLEDO,

ALMEIDA,

AVERBACH

et al. 2023

Arq. Gastroenterol.

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Background: Colorectal cancer (CRC) is an important public health problem, as it represents the world’s third most diagnosed neoplasm and the fourth cause of mortality. Its prevention can be divided into primary, secondary, demonstrated by tracking techniques, and tertiary, which consists of cancer diagnosis in symptomatic patients. Despite presenting a high incidence, the mortality rates decreased in the past two decades in developed countries, while the opposite happened in underdeveloped countries. That is attributed to the increase of colorectal cancer tracking programs in developed countries, which allows the precocious diagnosis and treatment of precancerous injuries and CRC. In that manner, the American Cancer Society divides the secondary tracking methods in exams based on feces samples and visual analysis of the colon and rectum, indicating its initiation starting at 45 years old in lower-risk patients. Objective: Verify in an analytical way the actions of colorectal cancer tracking held in Brazil, as to evaluate the necessity of implementation of a national tracking program of CRC. Methods: The methodology was based on a descriptive-quantitative secondary study that correlated the incidence of CRC, its morbidity and mortality, and the impact of the precocious tracking programs. It included activities not reported in medical literature through personal contacts with coordinators of regional programs to compare with the existent data in the literature. It was used as a variable for the tracking strategies the exams held, and their respective results. Results: It described nine programs held in different regions in Brazil, using two screening methods for CRC: a noninvasive method that consists of the research of blood hidden in feces, being the majority through the FIT method, and an invasive method, having the colonoscopy as its representant. These initiatives were effective in the detection of early forms of this disease. Conclusion: Despite the existence of several private tracking programs and the broad divulgation of the importance of the tracking and the early diagnosis of colorectal cancer, it was demonstrated that Brazil lacks a national program that patronizes the tracking methods, which reflects in the major prevalence of late diagnosis in the population.

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Section: Discussionmentioning

confidence: 99%

Analysis of the Tracking Initiatives of Colorectal Cancer in Brazil

TOLEDO,

ALMEIDA,

AVERBACH

et al. 2023

Arq. Gastroenterol.

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“…Until February 2017, 22.582 fecal occult blood tests have been made, where about 1.187 people had a positive result (abnormal) and were then recommended for a colonoscopy. 624 polyps (pre-malignant lesions) were found and removed over five years (GARDENAL, 2017;COY, 2013).…”

Section: List Of Tablesmentioning

confidence: 99%

Numerical analysis of multiscale methods for elliptic-parabolic problems with application in the cell dynamics during the formation of colorectal cancer

Carlos Mendonça Campos

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The human colon is prone to develop a cancer due to its cell renovation that consists in a large number of cell divisions per day located in small cavities of the colon epithelium, called crypts. The colon epithelium is filled by millions of crypts, and it is known that mutations in the cell proliferation process (inside the crypts) can lead to the carcinogenesis. Colonic cell proliferation can be modeled by using multiscales (FIGUEIREDO et al., 2013). In particular, we can use a reference crypt, as a microscale domain, that is periodically distributed in a macroscale domain that is a portion of the colon epithelium. The final model results in a coupled system formed by an elliptic and parabolic equations whose unknowns are the proliferative cell density and the exerted cell pressure.We present a homogenization for the final PDE model where it is supposed to exist a asymptotic expansion for the exact solution of the problem , see (CIORANESCU; DONATO, 1999). We apply a multiscale method based on finite elements (HMM-FEM) to approximate the homogenized solution as in (ABDULLE, 2009; ABDULLE, 2012;ABDULLE; HUBER, 2014). The coupling and the non-linearity of the system implies a more complex implementation and increase the computational effort, thus we first solve the elliptic problem and then the parabolic one to make it easier. As we can see later, that strategy does not affect the convergence rates.Furthermore, in a single scale, we study a supraconvergent method based on centered finite difference to nonuniform mesh which is equivalent to a fully discrete linear finite element method. Firstly we study convergence and stability of a simpler model and then we prove for s " 1, 2 order Oph s q convergence of solution and gradient if the exact solution is in H 1`s pΩq, see BARBEIRO; GRIGORIEFF, 2005). Numerical results illustrate the methods above. For the multiscale problem, we present a supraconvergent scheme which provides approximations to the coupled system with quadratic convergence rate. This is done by solving the homogenized problem with the supraconvergent method discussed before. Our last contribution is a multiscale model in development which can be useful to solve multiscale problems with the good convergence rates discussed above. That model is based on solving a microscale problem that will be used to construct a macroscale solution for the homogenized system. Numerical results for this model suggest a supraconvergence.

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