1 / 33

CANCER SCREENING PART II

CANCER SCREENING PART II. AIMGP Seminar Series January 2004 Joo-Meng Soh Edited by Gloria Rambaldini. OBJECTIVES. Understand the concept of cancer screening and the controversies surrounding this topic To learn the Canadian screening guidelines for Breast and Colorectal cancer

zeroun
Download Presentation

CANCER SCREENING PART II

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. CANCER SCREENINGPART II AIMGP Seminar Series January 2004 Joo-Meng Soh Edited by Gloria Rambaldini

  2. OBJECTIVES • Understand the concept of cancer screening and the controversies surrounding this topic • To learn the Canadian screening guidelines for Breast and Colorectal cancer • To be aware of other cancer screening guidelines available

  3. Principles of Cancer Screening • Screening of asymptomatic individuals to detect early cancers which may be curable • Use of diagnostic tests of high sensitivity • Diagnostic tests are suitable to the patient • Natural history of disease can be changed by intervention • Proposed early treatment should be beneficial and not harmful to the patient

  4. Case #1 • While on Team Medicine, you make the diagnosis of metastatic breast cancer in your 47 year old female patient • You think to yourself, “I wonder if she did Breast Self Examinations? Should she have received a mammogram? Would her cancer have been picked up earlier? Could she have been cured?”

  5. Guidelines Available

  6. Breast Cancer • Most frequently diagnosed cancer in women • In 2001, estimated: • 19,200 cases diagnosed • 5,500 deaths • 2nd leading cause of cancer death in women (after lung CA) Canadian Cancer Statistics 2001 http://66.59.133.166/stats/index.html

  7. Breast Cancer Statistics Risk of being Diagnosed with Breast Cancer Risk of Dying from Breast Cancer: 1 in 25

  8. Screening Maneuvers • Breast Self Examination (BSE) • Clinical Breast Examination (CBE) • Mammography

  9. Potential Benefits • Detection of Tumour at earlier stage • Improved Cosmetic result if found early • Reassurance if negative screening test

  10. Potential Harms • Radiation-induced Carcinoma from mammography • Est. risk of death from this is 8 per 100,000 women screened annually for 10 years beginning at age 40 • Unnecessary biopsies • Psychological stress of call-back • Possible false reassurance

  11. RCTs for BSE No reduction in breast cancer mortality or stage at diagnosis seen in two large scale on-going RCTs • Shanghai Trial (n=267 040 women) • Aged 31-64 • Results after first 5 years of follow-up • Russian/WHO Trial (n=122 471 women) • Aged 40-64 • Results after first 5 and 9 years of follow-up

  12. Breast Self-Examination ON THE OTHER HAND...... • RCTs showed a significant increase in: • number of physician visits for the evaluation of benign breast lesions • breast biopsy rates for benign lesions

  13. Breast Self Examination (BSE) • 1994 Canadian Task force on Preventive Health Care made BSE a Class C recommendation (insufficient evidence to recommend for or against BSE) • Due to recent trials, this screening tool now down-graded to class D (fair evidence to recommend that BSE be excluded from the periodic health exam)

  14. CBE & Mammography For Women Aged 50 - 69 • HIP (Health Insurance Plan) Trial • RRR of 0.55 in breast ca. mortality over 5 yrs • Swedish Trials • RRR of 0.29 in breast ca. mortality over 7-12 years follow-up • Canadian Trial comparing mammography over CBE • RRR of 0.03 (NS) at 7 years follow-up

  15. CBE & Mammography For Women Aged 50 - 69 Breast Cancer Screening with both CBE and mammography should be done for women aged 50-69 annually (Grade A Recommendation)

  16. CBE & Mammography For Women Aged 40 - 49 • CONFLICTING RESULTS!!! • Only one RCT designed specifically for women aged 40-49 did not have adequate power to exclude a clinically sig. benefit • Other RCT results are from post hoc subgroup analyses

  17. CBE & Mammography For Women Aged 40-49 • RRR of 18%-45% in breast cancer mortality at 10 years shown in 2 trials and 1 meta-analysis • No benefit was shown in 6 other trials • Recommendations: • Evidence does not support the use orexclusion of mammography for the periodic health exam in women aged 40-49 (Grade C)

  18. Back to the Case • “I wonder if she did BSEs” • Not currently recommended • “Should she have received a mammogram” • Unclear at this point in time; Women aged 40-49 should be informed of the risks and benefits of screening mammography and then assisted in making a decision” • “Would her cancer have been picked up earlier? Could she have been cured?” • Possibly....

  19. OTHER Guidelines  AAFP - American Academy of Family Physicians  ACOG - American College of Obstetricians and Gynecologists  ACS - American Cancer Society  CTFPHC Canadian Task force on Preventive Health Care  NIH - National Institutes of Health  USPSTF - U.S. Preventive Services Task Force

  20. Case #2 • During your GI rotation you consult on a 54 year old male with newly diagnosed metastatic colon cancer • Your team debates whether screening could have detected the cancer earlier? • Although the GI fellow swears by colonoscopies you wonder ‘what about all the hype regarding fecal occult testing vs sigmoidscopes vs barium enemas vs virtual c-scopes vs…”

  21. Guidelines Available

  22. COLORECTAL CANCER • Third most common cancer in Canada • In 2001, Estimated • New cases: 17,200 • Deaths: 6,400 Canadian Cancer Statistics 2001 http://66.59.133.166/stats/index.html

  23. Screening Tools • Fecal Occult Blood Testing • Sigmoidoscopy • Barium Enema • Colonoscopy

  24. Fecal Occult Blood (FOB) • Rationale – detect occult blood from cancers or large polyps • 3 consecutive stool samples at home • Evidence from 4 large-scale RCTs • Overall Sensitivity  25 - 50% • False positive rate  10% • Overall benefits are statistically sig. but small • Number needed to screen for 10 years to avert one death from colorectal cancer = 1173

  25. Sigmoidoscopy • May reduce the risk of death from Colorectal cancer (3 case control studies) • 3 RCTs suggest it may be superior in detecting adenomas and possibly cancer than FOBT (but no mortality data) • Potential Harms: • Bowel perforation in 1.4 per 10,000 exams

  26. Colonoscopy • Currently no direct evidence on mortality benefit from colonoscopy as a screening maneuver • Potential Harms: • Bowel perforation in 10 per 10,000 exams

  27. Comparison of all Three • Recent NEJM article: Aug. 23, 2001 “One-Time Screening for Colorectal Cancer with Combined FOBT and Examination of the Distal Colon”, Lieberman D et al • n = 2885 patients • All patients provided stool for FOBT, then underwent Colonoscopy (“sigmoidoscopy” was defined as examination of the rectum and sigmoid colon during colonoscopy)

  28. Comparison of all Three • Only 23.9% of patients with advanced neoplasia had a positive FOBT • Sigmoidoscopy identified only 70.3% of all subjects with advanced neoplasia • Combined FOBT and sigmoidoscopy identified only 75.8% of subjects with advanced neoplasia In other words, combined FOBT and sigmoidoscopy would have missed 25% of the colorectal cancers

  29. Canadian Recommendations • Good evidence to include annual or biennial FOBT (Grade A Recommendation) • Fair evidence to include Flexible Sigmoidoscopy (Grade B Recommendation) • Insufficient evidence to make recommendations about whether only one or both tests should be performed (Grade C) • Insufficient evidence to include or exclude colonoscopy as initial screening test Grade C) Colorectal Cancer Screening – Recommendations from the Canadian Task force on Preventive Health CareCMAJ 2001; 165(2): 206 - 208

  30. Other Guidelines Outdated • AAFP - American Academy of Family Physicians  ACOG - American College of Obstetricians and Gynecologists  ACS - American Cancer Society  AMA - American Medical Association  AGA - American Gastroenterological Association  CTFPHC - Canadian Task Force on Preventive Health Care  USPSTF - U.S. Preventive Services Task Force

  31. Back to the Case • Screening can result in the reduction in CRC related mortality • Recommendations thus far include routine FOBT and sigmoidoscopy • Routine colonoscopy is not supported by good evidence at present • Like all screening tests…patient counseling will guide you and the patient

  32. Other References • Cancer Screening Guidelines, American Family Physician 2001, 63(6):1101-1112 • Summarizes in table format the guidelines published by multiple organizations • Preventive Health Care, 2001 update: screening mammography among women aged 40-49 years at average risk of breast cancer, CMAJ 2001; 164(4): 469-76 • Preventive Health Care, 20001 update: Should women be routinely taught BSE to screen for breast cancer, CMAJ 2001; 164(13): 1837-46

More Related