Impact of Cancer Diagnosis and Chemotherapy on Mammography Use

1. Impact of Cancer Diagnosis and Chemotherapy on Mammography Use Xinhua Yu, M.B., Ph.D. A. Marshall McBean, M.D., M.Sc. Beth A. Virnig, Ph.D., M.P.H Division of Health Policy and Management University of Minnesota Annual Research Meeting: June 9, 2008

2. Introduction • Colorectal cancer is the second leading cancer cause of death in the US • Average age of diagnosis: 71 • Life expectancy for elderly women at age 65: 20 years • 39% localized stage, and 36% regional stage • Relative five year survival rates: 90% for localized, 68% for regional stage • In 2005, over 1 million colorectal cancer survivors, 563,408 women • Treatment: surgery, radiation, and chemotherapy • Chemotherapy not recommended for stage I and II colon cancer • A second primary cancer is becoming a significant problem among cancer survivors • No evidence of differences in the risk of breast cancer between female colorectal cancer survivors and women with no history of cancer

3. Hypotheses • Patient’s health belief and behavior may play a significant role in receiving chemotherapy and mammograms • Patients with proactive health behavior are more likely to receive mammograms and chemotherapy • Mammography use among newly diagnosed colorectal cancer patients will decrease after the cancer diagnosis because of the competing demands of cancer management

4. Data Source • Linked SEER-Medicare data, 2006 batch • Women diagnosed of stage 0, I, II, and III colorectal cancer from 1996 to 2001 • Unstaged cancer cases were excluded • Aged 67-79 at the time of cancer diagnosis • Cost-effectiveness of mammography use • Chemotherapy use is lower among patients older than 80 • Each cancer patient was matched up to 5 non-cancer controls by age, race, state residence • The time windows before and after the cancer diagnosis were aligned between cancer patients and non-cancer controls • Chemotherapy was identified using both administrative and agents claims • Restricted to chemotherapy within one year

5. Analysis • Analysis is based on the matched design • Important co-variables include race, age, hospital type, state buy-in status, zip code median household income, Charlson score, medical oncologist visit, and cancer stage • Stratified by prior mammography use and chemotherapy use • Patterns of mammography use after the cancer diagnosis • Survival curves for the time to the first mammogram and cumulative mammography rates • Mammography rates during the third and fourth year after the cancer diagnosis • Conditional logistic regression

6. Results

7. Comparison of Characteristics between Cancer Patients and Matched controls

8. Chemotherapy Use by Prior Mammography Use among Women with Colorectal cancer

11. Mammography Rates during the Third and Fourth Year after the Cancer Diagnosis among Women, by Chemotherapy Status

12. Mammography Rates during the Third and Fourth Year after the Cancer Diagnosis among Women Having a Prior Mammogram

13. Mammography Rates during the Third and Fourth Year after the Cancer Diagnosis among Women NOT Having a Prior Mammogram

14. Conclusion • Chemotherapy rate was higher among those who had mammography use before the cancer diagnosis than those who did not • A new cancer diagnosis and chemotherapy treatment may reduce mammography use among some patients with advanced cancer stages • The mammography rate after the cancer diagnosis increased among patients with less advanced cancer stages • Those with prior mammograms consistently had higher mammography rates after cancer diagnosis • Among those without prior mammograms, the differences in mammography rates after cancer diagnosis were even greater

15. Discussion • Competing demands exist between cancer management and mammography use, as seen in those with stage III disease • Among those with less advanced cancer stage, the increase of mammography use may be due to the enhanced positive health beliefs or the favorable change of heath beliefs among these patients • Given the high survival rate and long life-expectancy among colorectal cancer patients, providers should continue to recommend mammograms to them

16. Thank You!