Minnesota Colon Cancer Control Study: Difference between revisions
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This Wiki article provides a structured summary a previously published research study. There are two purposes for summarizing previously published research articles in a standard format: | |||
This | # Increase the reader's ability to understand the contents of the article. Research has shown that physicians have difficulty reading medical research articles. Physicians have trouble quantifying benefits of treatments and diagnostic tests <ref name="pmid3701813">{{cite journal |author=Bergman D, Pantell R |title=The impact of reading a clinical study on treatment decisions of physicians and residents |journal=J Med Educ |volume=61 |issue=5 |pages=380-6 |year=1986 |id=PMID 3701813}}</ref><ref name="pmid12213145">{{cite journal |author=Beasley B, Woolley D |title=Evidence-based medicine knowledge, attitudes, and skills of community faculty |journal=J Gen Intern Med |volume=17 |issue=8 |pages=632-9 |year=2002 |id=PMID 12213145}}</ref><ref name="pmid7315859">{{cite journal |author=Berwick D, Fineberg H, Weinstein M |title=When doctors meet numbers |journal=Am J Med |volume=71 |issue=6 |pages=991-8 |year=1981 |id=PMID 7315859}}</ref>. A specific example of this difficulty is that physicians have difficulty interpreting relative versus absolute effects <ref name="pmid7950558">{{cite journal |author=Bucher H, Weinbacher M, Gyr K |title=Influence of method of reporting study results on decision of physicians to prescribe drugs to lower cholesterol concentration |journal=BMJ |volume=309 |issue=6957 |pages=761-4 |year=1994 |id=PMID 7950558}}</ref> | ||
# Provide building blocks that Wiki authors can reference to when writing about this topic (in this case, screening for colorectal cancer). The format below is based on prior work about "critically appraised topics" (PMID 15588311, PMID 15579428, PMID 15204609, PMID 15105349, PMID 14728311, PMID 11702349). | |||
===Summary | ''This page is under development; for discussion please see: | ||
*[http://pilot.citizendium.org/wiki?title=Talk:PMID_8474513&action=edit The discussion page for this article] | |||
*[http://en.wikipedia.org/wiki/Wikipedia:Articles_for_deletion/PMID_8474513 Discussion at Wikipedia] about why an earlier version of this article was deleted from WikiPedia. | |||
="Reducing mortality from colorectal cancer by screening for fecal occult blood. Minnesota Colon Cancer Control Study"= | |||
This is a structured summary of a research study entitled "Reducing mortality from colorectal cancer by screening for fecal occult blood. Minnesota Colon Cancer Control Study"<ref name="pmid8474513">{{cite journal | author = Mandel J, Bond J, Church T, Snover D, Bradley G, Schuman L, Ederer F | title = Reducing mortality from colorectal cancer by screening for fecal occult blood. Minnesota Colon Cancer Control Study | journal = N Engl J Med | volume = 328 | issue = 19 | pages = 1365-71 | year = 1993 | id = PMID 8474513 | url = http://content.nejm.org/cgi/content/full/328/19/1365}}"</ref> originally published in 1993 in the [[New England Journal of Medicine]]. | |||
==Summary of the original article== | |||
A [[randomized controlled trial]] of 46,551 participants aged 50 to 80 years were randomized to one of: | A [[randomized controlled trial]] of 46,551 participants aged 50 to 80 years were randomized to one of: | ||
*screening for colorectal cancer once a year using the [[stool guaiac test]]. Per the text of the paper, 'six guaiac-impregnated paper slides with two smears from each of three consecutive stools'. | *screening for [[colorectal cancer]] once a year using the [[stool guaiac test]]. Per the text of the paper, 'six guaiac-impregnated paper slides with two smears from each of three consecutive stools'. | ||
*screening every two years using the [[stool guaiac test]]. Per the text of the paper, 'six guaiac-impregnated paper slides with two smears from each of three consecutive stools'. | *screening every two years using the [[stool guaiac test]]. Per the text of the paper, 'six guaiac-impregnated paper slides with two smears from each of three consecutive stools'. | ||
*[[control group]]. | *[[control group]]. | ||
==Results== | |||
{| class="wikitable" style="width: | These results are limited to the annually screened group versus the control group as the effect of biennial screening was not significant. | ||
{| class="wikitable" style="width:50%" | |||
|+Cross tabulation | |+Cross tabulation | ||
|- | |- | ||
! | ! | ||
! Deaths from<br> | ! Deaths from<br>colorectal cancer | ||
! Alive | ! Alive | ||
! Totals | ! Totals | ||
| Line 32: | Line 40: | ||
| 30765 | | 30765 | ||
| | | | ||
|- | |||
| colspan="4" | (this table was reconstructed by using the totals in [http://content.nejm.org/cgi/content/full/328/19/1365/T1 Table 1] of the article and using the outcomes in [http://content.nejm.org/cgi/content/full/328/19/1365/T4 Table 4] of the article) | |||
|} | |} | ||
The numbers in the cross tabulation lead to the following event rates: | |||
{| class="wikitable" style="width:50%" | |||
|+Event rates for colorectal cancer mortality | |||
|- | |||
! Group | |||
! Rate | |||
! [[Confidence interval]] | |||
|- | |||
| Annual screening | |||
| 0.588% | |||
| align="center" | (4.61 to 7.15) | |||
|- | |||
| Control | |||
| 0.883% | |||
| align="center" | 7.26 to 10.40) | |||
|- | |||
|} | |||
These | These event rates lead to the following measures of efficacy: | ||
{| class="wikitable" style="width: | {| class="wikitable" style="width:50%" | ||
|+Measures of Efficacy | |+Measures of Efficacy | ||
|- | |- | ||
| Line 54: | Line 76: | ||
|} | |} | ||
Per the authors, 'the rate in the annually screened group, but not in the biennially screened group, was significantly lower than that in the control group'. The p-value is not in the article. | Per the authors, 'the rate in the annually screened group, but not in the biennially screened group, was significantly lower than that in the control group'. The [[p-value]] is not in the article. | ||
==Are the results significant?== | |||
#To assess whether the results are [[statistically significant]], not only the [[p-value]] is important, but factors such as [[publication bias]] that might influence the p-value are important. To alter the a priori estimate of the [[null hypothesis]], click here. (''this paragraph needs to be much more user friendly'') | #To assess whether the results are [[statistically significant]], not only the [[p-value]] is important, but factors such as [[publication bias]] that might influence the [[p-value]] are important. To alter the a priori estimate of the [[null hypothesis]], click here. (''this paragraph needs to be much more user friendly'') | ||
#Clinical significance must also be considered. For example, the results may be statistically significant, but the [[number needed to treat]] may reveal that too few patients will benefit for patients to be willing to accept expense and effort of the treatment. | #Clinical significance must also be considered. For example, the results may be statistically significant, but the [[number needed to treat]] may reveal that too few patients will benefit for patients to be willing to accept expense and effort of the treatment. | ||
==How will these result be changed in patients at higher or lower risk of the outcome?== | |||
The risk of death from [[colorectal cancer]] in this study is 0.883% in the unscreened group. For patients who have risk factors that make their risk higher or lower than this number, their benefit will be higher or lower. Use [[http://medinformatics.uthscsa.edu/cgi-bin/calc-rx.pl?eer=0.588&cer=0.883&outcome=- this link]] to adjust the baseline risk. | The risk of death from [[colorectal cancer]] in this study is 0.883% in the unscreened group. For patients who have risk factors that make their risk higher or lower than this number, their benefit will be higher or lower. Use [[http://medinformatics.uthscsa.edu/cgi-bin/calc-rx.pl?eer=0.588&cer=0.883&outcome=- this link]] to adjust the baseline risk. | ||
==Follow-up== | |||
The results of the is study after 18 years of follow-up have been published <ref name="pmid11096167">{{cite journal | author = Mandel J, Church T, Bond J, Ederer F, Geisser M, Mongin S, Snover D, Schuman L | title = The effect of fecal occult-blood screening on the incidence of colorectal cancer | journal = N Engl J Med | volume = 343 | issue = 22 | pages = 1603-7 | year = 2000 | id = PMID 11096167 | url = http://content.nejm.org/cgi/content/full/343/22/1603}}</ref> | The results of the is study after 18 years of follow-up have been published.<ref name="pmid11096167">{{cite journal | author = Mandel J, Church T, Bond J, Ederer F, Geisser M, Mongin S, Snover D, Schuman L | title = The effect of fecal occult-blood screening on the incidence of colorectal cancer | journal = N Engl J Med | volume = 343 | issue = 22 | pages = 1603-7 | year = 2000 | id = PMID 11096167 | url = http://content.nejm.org/cgi/content/full/343/22/1603}}</ref> | ||
==References== | ==References== | ||
Revision as of 13:26, 23 January 2007
This Wiki article provides a structured summary a previously published research study. There are two purposes for summarizing previously published research articles in a standard format:
- Increase the reader's ability to understand the contents of the article. Research has shown that physicians have difficulty reading medical research articles. Physicians have trouble quantifying benefits of treatments and diagnostic tests [1][2][3]. A specific example of this difficulty is that physicians have difficulty interpreting relative versus absolute effects [4]
- Provide building blocks that Wiki authors can reference to when writing about this topic (in this case, screening for colorectal cancer). The format below is based on prior work about "critically appraised topics" (PMID 15588311, PMID 15579428, PMID 15204609, PMID 15105349, PMID 14728311, PMID 11702349).
This page is under development; for discussion please see:
- The discussion page for this article
- Discussion at Wikipedia about why an earlier version of this article was deleted from WikiPedia.
"Reducing mortality from colorectal cancer by screening for fecal occult blood. Minnesota Colon Cancer Control Study"
This is a structured summary of a research study entitled "Reducing mortality from colorectal cancer by screening for fecal occult blood. Minnesota Colon Cancer Control Study"[5] originally published in 1993 in the New England Journal of Medicine.
Summary of the original article
A randomized controlled trial of 46,551 participants aged 50 to 80 years were randomized to one of:
- screening for colorectal cancer once a year using the stool guaiac test. Per the text of the paper, 'six guaiac-impregnated paper slides with two smears from each of three consecutive stools'.
- screening every two years using the stool guaiac test. Per the text of the paper, 'six guaiac-impregnated paper slides with two smears from each of three consecutive stools'.
- control group.
Results
These results are limited to the annually screened group versus the control group as the effect of biennial screening was not significant.
| Deaths from colorectal cancer |
Alive | Totals | |
|---|---|---|---|
| Annual screening | 82 | 15488 | 15570 |
| Control | 117 | 15277 | 15394 |
| Totals | 199 | 30765 | |
| (this table was reconstructed by using the totals in Table 1 of the article and using the outcomes in Table 4 of the article) | |||
The numbers in the cross tabulation lead to the following event rates:
| Group | Rate | Confidence interval |
|---|---|---|
| Annual screening | 0.588% | (4.61 to 7.15) |
| Control | 0.883% | 7.26 to 10.40) |
These event rates lead to the following measures of efficacy:
| Absolute risk reduction | 0.3% |
| Number needed to treat | 339 |
| Relative risk reduction | 33.4% |
Per the authors, 'the rate in the annually screened group, but not in the biennially screened group, was significantly lower than that in the control group'. The p-value is not in the article.
Are the results significant?
- To assess whether the results are statistically significant, not only the p-value is important, but factors such as publication bias that might influence the p-value are important. To alter the a priori estimate of the null hypothesis, click here. (this paragraph needs to be much more user friendly)
- Clinical significance must also be considered. For example, the results may be statistically significant, but the number needed to treat may reveal that too few patients will benefit for patients to be willing to accept expense and effort of the treatment.
How will these result be changed in patients at higher or lower risk of the outcome?
The risk of death from colorectal cancer in this study is 0.883% in the unscreened group. For patients who have risk factors that make their risk higher or lower than this number, their benefit will be higher or lower. Use [this link] to adjust the baseline risk.
Follow-up
The results of the is study after 18 years of follow-up have been published.[6]
References
- ↑ Bergman D, Pantell R (1986). "The impact of reading a clinical study on treatment decisions of physicians and residents". J Med Educ 61 (5): 380-6. PMID 3701813.
- ↑ Beasley B, Woolley D (2002). "Evidence-based medicine knowledge, attitudes, and skills of community faculty". J Gen Intern Med 17 (8): 632-9. PMID 12213145.
- ↑ Berwick D, Fineberg H, Weinstein M (1981). "When doctors meet numbers". Am J Med 71 (6): 991-8. PMID 7315859.
- ↑ Bucher H, Weinbacher M, Gyr K (1994). "Influence of method of reporting study results on decision of physicians to prescribe drugs to lower cholesterol concentration". BMJ 309 (6957): 761-4. PMID 7950558.
- ↑ Mandel J, Bond J, Church T, Snover D, Bradley G, Schuman L, Ederer F (1993). "Reducing mortality from colorectal cancer by screening for fecal occult blood. Minnesota Colon Cancer Control Study". N Engl J Med 328 (19): 1365-71. PMID 8474513. "
- ↑ Mandel J, Church T, Bond J, Ederer F, Geisser M, Mongin S, Snover D, Schuman L (2000). "The effect of fecal occult-blood screening on the incidence of colorectal cancer". N Engl J Med 343 (22): 1603-7. PMID 11096167.