From: Benefits of Colonoscopic Surveillance and Prophylactic Colectomy in Patients with Hereditary
Nonpolyposis Colorectal Cancer Mutations
Ann Intern Med. 1998;129(10):787-796. doi:10.7326/0003-4819-129-10-199811150-00007
Figure Legend:
General model framework.Schematic overview of Markov model. A cohort of 25-year-old carriers of a mutation for hereditary nonpolyposis colorectal cancer who are cancer-free enter the model. Each circle represents
states of health within the model. Each of the four main categories, depicted in bold, contains several subsets that depend on whether the patient is undergoing surveillance (surveillance status), undergoes colectomy
(colon status), or has a polyp diagnosed and on the patient's stage of cancer (if colorectal cancer has occurred). The arrows represent potential transitions between health states and transition probabilities that vary
depending on the strategy. Each year, a patient may remain in the same health state, die, or move to another health state, as shown in the flow diagrams.
Date of download: 7/28/2017
Copyright © American College of Physicians. All rights reserved.
From: Benefits of Colonoscopic Surveillance and Prophylactic Colectomy in Patients with Hereditary
Nonpolyposis Colorectal Cancer Mutations
Ann Intern Med. 1998;129(10):787-796. doi:10.7326/0003-4819-129-10-199811150-00007
Figure Legend:
Schematic representation of surveillance and colectomy if adenoma is found.Top.Bottom.The patient enters the Markov tree (the encircled letter M), which depicts the clinical events that may occur during each 1-year
period as a patient is followed until death. Circles represent chance nodes. Because surveillance occurs every 3 years, a patient may or may not undergo surveillance in a given year. Colorectal cancer may be diagnosed
on the basis of symptoms or at the time of colonoscopy. Death may occur as a result of colorectal cancer, surgical or surveillance procedures, or causes not related to colorectal cancer. Surveillance. If colorectal cancer
develops, segmental resection of the cancer is performed; the patient must continue to undergo surveillance and is at risk for a second primary tumor. Surveillance and colectomy if adenoma is found. If colorectal cancer
or an adenoma develops, colectomy is performed. If subtotal colectomy is performed, the patient must continue to undergo surveillance and is at risk for a second primary tumor. If total proctocolectomy with ileoanal
anastomosis is performed, the risk for a second primary cancer is eliminated and continued surveillance is not necessary. Other colectomy strategies examined follow similar paths, with variations of timing of colectomy
based on the particular strategy being evaluated.
Date of download: 7/28/2017
Copyright © American College of Physicians. All rights reserved.
From: Benefits of Colonoscopic Surveillance and Prophylactic Colectomy in Patients with Hereditary
Nonpolyposis Colorectal Cancer Mutations
Ann Intern Med. 1998;129(10):787-796. doi:10.7326/0003-4819-129-10-199811150-00007
Figure Legend:
Two-way sensitivity analysis varying the utilities associated with total and subtotal colectomy and their effects on quality-adjusted life expectancy.The lines represent thresholds at which the strategy leading to the
greatest quality-adjusted life expectancy changes.
Date of download: 7/28/2017
Copyright © American College of Physicians. All rights reserved.