Abstract
INTRODUCTION
Colorectal cancer (CRC) is the third most common cancer in the United States and a leading cause of cancer related mortality. Routine screening decreases incidence and mortality; however rates of screening remain low. Physician recommendation is a key determinant of screening rates; thus, physician availability may also influence CRC incidence and mortality.
METHODS
Data on CRC incidence and stage at diagnosis was obtained for each county in Pennsylvania from the Pennsylvania cancer registry. Physician density (per 100,000 population) was calculated for each county using physician counts from the American Medical Association. Pearson correlation coefficients and linear regression models were used to examine the association between physician density and CRC incidence and outcomes.
RESULTS
Primary care physician density (Pearson’s correlation coefficient: -0.25, p = 0.05) and gastroenterologist density (correlation coefficient -0.25, p = 0.04) inversely correlated with county-level incidence of late-stage CRC. However, this association was seen only in non-metropolitan counties or those with low population density. On linear regression, non-metropolitan counties which had a high density of gastroenterologists had an incidence of late-stage CRC that was lower by 4/100,000 (reduction of 14%). Low population density counties had lower incidence of late-stage CRC by 5/100,000 (reduction of 17%) when they had at least 3.3 gastroenterologists/100,000 population compared to counties with a lower gastroenterologist-per-population ratio. Gastroenterologist density did not correlate with reduced late-stage CRC incidence prior to institution of Medicare coverage for colonoscopy for routine CRC screening.
CONCLUSION
Higher gastroenterologist or PCP density is associated with 14-17% lower incidence of late-stage CRC in non-metropolitan counties or those with low population density. Efforts at increasing physician supply should target these underserved areas.
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References
Rex DK, Johnson DA, Anderson JC, Schoenfeld PS, Burke CA, Inadomi JM. American College of Gastroenterology guidelines for colorectal cancer screening 2009 [corrected]. Am J Gastroenterol. 2009;104:739–50.
Smith RA, von Eschenbach AC, Wender R, Levin B, Byers T, Rothenberger D, Brooks D, Creasman W, Cohen C, Runowicz C, Saslow D, Cokkinides V, Eyre H. American Cancer Society guidelines for the early detection of cancer: update of early detection guidelines for prostate, colorectal, and endometrial cancers. Also: update 2001--testing for early lung cancer detection. CA Cancer J Clin. 2001;51:38–75. quiz 77-80.
Winawer S, Fletcher R, Rex D, Bond J, Burt R, Ferrucci J, Ganiats T, Levin T, Woolf S, Johnson D, Kirk L, Litin S, Simmang C. Colorectal cancer screening and surveillance: clinical guidelines and rationale-Update based on new evidence. Gastroenterology. 2003;124:544–60.
Screening for colorectal cancer: U.S. Preventive Services Task Force recommendation statement. Ann Intern Med. 2008;149:627-37.
Whitlock EP, Lin JS, Liles E, Beil TL, Fu R. Screening for colorectal cancer: a targeted, updated systematic review for the U.S. Preventive Services Task Force. Ann Intern Med. 2008;149:638–58.
Fazio L, Cotterchio M, Manno M, McLaughlin J, Gallinger S. Association between colonic screening, subject characteristics, and stage of colorectal cancer. Am J Gastroenterol. 2005;100:2531–9.
Gross CP, Andersen MS, Krumholz HM, McAvay GJ, Proctor D, Tinetti ME. Relation between Medicare screening reimbursement and stage at diagnosis for older patients with colon cancer. Jama. 2006;296:2815–22.
Ananthakrishnan AN, Schellhase KG, Sparapani RA, Laud PW, Neuner JM. Disparities in colon cancer screening in the Medicare population. Arch Intern Med. 2007;167:258–64.
Ko CW, Kreuter W, Baldwin LM. Effect of Medicare coverage on use of invasive colorectal cancer screening tests. Arch Intern Med. 2002;162:2581–6.
Ko CW, Kreuter W, Baldwin LM. Persistent demographic differences in colorectal cancer screening utilization despite Medicare reimbursement. BMC Gastroenterol. 2005;5:10.
Nadel MR, Blackman DK, Shapiro JA, Seeff LC. Are people being screened for colorectal cancer as recommended? Results from the National Health Interview Survey. Prev Med. 2002;35:199–206.
Seeff LC, Nadel MR, Klabunde CN, Thompson T, Shapiro JA, Vernon SW, Coates RJ. Patterns and predictors of colorectal cancer test use in the adult U.S. population. Cancer. 2004;100:2093–103.
Seeff LC, Shapiro JA, Nadel MR. Are we doing enough to screen for colorectal cancer? Findings from the 1999 Behavioral Risk Factor Surveillance System. J Fam Pract. 2002;51:761–6.
Baldwin LM, Dobie SA, Billingsley K, Cai Y, Wright GE, Dominitz JA, Barlow W, Warren JL, Taplin SH. Explaining black-white differences in receipt of recommended colon cancer treatment. J Natl Cancer Inst. 2005;97:1211–20.
Chien C, Morimoto LM, Tom J, Li CI. Differences in colorectal carcinoma stage and survival by race and ethnicity. Cancer. 2005;104:629–39.
Coughlin SS, Richards TB, Thompson T, Miller BA, VanEenwyk J, Goodman MT, Sherman RL. Rural/Nonrural differences in colorectal cancer incidence in the United States, 1998-2001. Cancer. 2006;107:1181–8.
Gomez SL, O'Malley CD, Stroup A, Shema SJ, Satariano WA. Longitudinal, population-based study of racial/ethnic differences in colorectal cancer survival: impact of neighborhood socioeconomic status, treatment and comorbidity. BMC Cancer. 2007;7:193.
Gorey KM, Vena JE. The association of near poverty status with cancer incidence among black and white adults. J Community Health. 1995;20:359–66.
Gorey KM, Vena JE. Cancer differentials among US blacks and whites: quantitative estimates of socioeconomic-related risks. J Natl Med Assoc. 1994;86:209–15.
Henry KA, Niu X, Boscoe FP. Geographic disparities in colorectal cancer survival. Int J Health Geogr. 2009;8:48.
Paquette I, Finlayson SR. Rural versus urban colorectal and lung cancer patients: differences in stage at presentation. J Am Coll Surg. 2007;205:636–41.
Roetzheim RG, Pal N, Gonzalez EC, Ferrante JM, Van Durme DJ, Krischer JP. Effects of health insurance and race on colorectal cancer treatments and outcomes. Am J Public Health. 2000;90:1746–54.
Trivers KF, Shaw KM, Sabatino SA, Shapiro JA, Coates RJ. Trends in colorectal cancer screening disparities in people aged 50-64 years, 2000-2005. Am J Prev Med. 2008;35:185–93.
Beydoun HA, Beydoun MA. Predictors of colorectal cancer screening behaviors among average-risk older adults in the United States. Cancer Causes Control. 2008;19:339–59.
Guerra CE, Schwartz JS, Armstrong K, Brown JS, Halbert CH, Shea JA. Barriers of and facilitators to physician recommendation of colorectal cancer screening. J Gen Intern Med. 2007;22:1681–8.
Levy BT, Nordin T, Sinift S, Rosenbaum M, James PA. Why hasn't this patient been screened for colon cancer? An Iowa Research Network study. J Am Board Fam Med. 2007;20:458–68.
Zarychanski R, Chen Y, Bernstein CN, Hebert PC. Frequency of colorectal cancer screening and the impact of family physicians on screening behaviour. Cmaj. 2007;177:593–7.
Roetzheim RG, Pal N, van Durme DJ, Wathington D, Ferrante JM, Gonzalez EC, Krischer JP. Increasing supplies of dermatologists and family physicians are associated with earlier stage of melanoma detection. J Am Acad Dermatol. 2000;43:211–8.
Campbell RJ, Ramirez AM, Perez K, Roetzheim RG. Cervical cancer rates and the supply of primary care physicians in Florida. Fam Med. 2003;35:60–4.
Ferrante JM, Gonzalez EC, Pal N, Roetzheim RG. Effects of physician supply on early detection of breast cancer. J Am Board Fam Pract. 2000;13:408–14.
Fleisher JM, Lou JQ, Farrell M. Relationship between physician supply and breast cancer survival: a geographic approach. J Community Health. 2008;33:179–82.
Roetzheim RG, Gonzalez EC, Ramirez A, Campbell R, van Durme DJ. Primary care physician supply and colorectal cancer. J Fam Pract. 2001;50:1027–31.
Roetzheim RG, Pal N, Gonzalez EC, Ferrante JM, Van Durme DJ, Ayanian JZ, Krischer JP. The effects of physician supply on the early detection of colorectal cancer. J Fam Pract. 1999;48:850–8.
Shipp MP, Desmond R, Accortt N, Wilson RJ, Fouad M, Eloubeidi MA. Population-based study of the geographic variation in colon cancer incidence in Alabama: relationship to socioeconomic status indicators and physician density. South Med J. 2005;98:1076–82.
Krieger N, Chen JT, Waterman PD, Soobader MJ, Subramanian SV, Carson R. Choosing area based socioeconomic measures to monitor social inequalities in low birth weight and childhood lead poisoning: The Public Health Disparities Geocoding Project (US). J Epidemiol Community Health. 2003;57:186–99.
Perrin JM, Valvona J. Does increased physician supply affect quality of care? Health Aff (Millwood). 1986;5:63–72.
Gulliford MC, Jack RH, Adams G, Ukoumunne OC. Availability and structure of primary medical care services and population health and health care indicators in England. BMC Health Serv Res. 2004;4:12.
Mandel JS, Bond JH, Church TR, Snover DC, Bradley GM, Schuman LM, Ederer F. Reducing mortality from colorectal cancer by screening for fecal occult blood. Minnesota Colon Cancer Control Study. N Engl J Med. 1993;328:1365–71.
Lang CA, Ransohoff DF. Fecal occult blood screening for colorectal cancer. Is mortality reduced by chance selection for screening colonoscopy? Jama. 1994;271:1011–3.
Kahi CJ, Imperiale TF, Juliar BE, Rex DK. Effect of screening colonoscopy on colorectal cancer incidence and mortality. Clin Gastroenterol Hepatol. 2009;7:770–5. quiz 711.
Pathman DE, Ricketts TC 3rd, Konrad TR. How adults' access to outpatient physician services relates to the local supply of primary care physicians in the rural southeast. Health Serv Res. 2006;41:79–102.
AAMC. AAMC Statement on the Physician Workforce. http://www.aamc.org/workforce/workforceposition.pdf. Accessed May, 2010.
Mitka M. Looming shortage of physicians raises concerns about access to care. JAMA. 2007;297:1045–6.
The Lewin Group I. The impact of improved colorectal cancer screening rates on adequacy of future supply of gastroenterologists. http://www.olympusamerica.com/CRCadvocacy/docs/Lewin-Gastroenterologist-Report.pdf. Accessed May, 2010.
Penchansky R, Thomas JW. The concept of access: definition and relationship to consumer satisfaction. Med Care. 1981;19(2):127–40.
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Ananthakrishnan, A.N., Hoffmann, R.G. & Saeian, K. Higher Physician Density is Associated with Lower Incidence of Late-stage Colorectal Cancer. J GEN INTERN MED 25, 1164–1171 (2010). https://doi.org/10.1007/s11606-010-1457-z
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DOI: https://doi.org/10.1007/s11606-010-1457-z