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 ManagementUniversity of Minnesota

Annual Research Meeting: June 9, 2008

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

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

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

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

Results

Comparison of Characteristics between Cancer Patients and Matched controls      Cancer patients

Non-cancer controls  

      (8,294) (38,992)  

Age Mean (SD) 73.6 (3.7) 73.7 (3.5) p=0.0004

67-69 16.6% 19.2% p <0.001

70-74 37.5% 36.1%

75-79 45.9% 44.7%

Race/ethnicity White 85.5% 85.7%

Black 7.7% 7.5%

Other 6.8% 6.8%

State buy-in status yes 19.0% 19.2%

Zip code median <38,000 32.0% 28.4% p <0.001

household income 38,001-50,000 36.9% 34.9%

50,001+ 31.1% 36.8%

Charlson score 0 31.6% 40.7% p <0.001

1 33.5% 29.2%

2 18.0% 15.6%

3+ 17.0% 14.6%

Chemotherapy Use by Prior Mammography Use among Women with Colorectal cancer

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

0/I II III

AJCC stage

Ch

em

oth

era

py

ra

te

Mammogram No

Mammogram Yes

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

After cancer diagnosis

Chemotherapy Cancer

patientsNon-cancer

controls Odds Ratio (95% CI)

Yes 58.8% 50.5% 1.17 (1.10 - 1.25)

No 52.8% 50.2% 1.05 (1.01 - 1.10)

Total 54.9% 50.3% 1.10 (1.06 - 1.13)

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

AJCC stage ChemotherapyCancer

patientsNon-cancer

controlsOdds Ratio (95%

CI)

0/I Yes 77.9% 68.1% 1.18 (0.87-1.59)

No 73.1% 71.7% 1.02 (0.93-1.17)

II Yes 77.5% 73.9% 1.02 (0.90-1.16)

No 67.9% 71.2% 0.97 (0.87-1.07)

III Yes 75.2% 70.7% 1.09 (0.97-1.22)

No 52.4% 68.0% 0.75 (0.54-1.04)

AJCC stage Chemotherapy

Cancer patients

Non-cancer controls

Odds Ratio (95% CI)

0/I Yes 48.9% 30.9% 1.57 (1.06-2.33)

No 38.4% 30.6% 1.28 (1.16-1.41)

II Yes 45.4% 32.4% 1.47 (1.26-1.74)

No 31.5% 29.5% 1.06 (0.92-1.21)

III Yes 45.4% 32.1% 1.46 (1.27-1.68)

No 22.1% 28.3% 0.71 (0.50-0.99)

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

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

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

Thank You!