Factors Associated with Bilateral vs. Unilateral Mastectomy in a Diverse, Population-based Sample of Breast Cancer Patients Sarah T. Hawley, PhD, MPH University of Michigan Ann Arbor VA Medical Center

Acknowledgements Amy Alderman, MD Reshma Jagsi, MD, DPhil Jennifer Griggs, MD, MPH Nancy Janz PhD Ann Hamilton, PhD John Graff, PhD Steven Katz, MD University of Michigan Ann Arbor VA Medical Center Los Angeles and Detroit Metropolitan Area SEER Registries University of Southern California and Wayne State University Funded by the National Cancer Institute (R01 CA088370)

Background Rates of bilateral mastectomy among women with cancer in one breast have been increasing over the past decade Bilateral mastectomy has been associated with younger age, white race, previous cancer diagnosis, lobular histology (Tuttle 2009, Tuttle 2007)

Gaps in Research Few studies have patient report of receipt of bilateral mastectomy Lack of good measures of the role of family history or genetic predisposition No large studies have included patient attitudes toward surgical treatment decision making Decision-making for bilateral vs. unilateral mastectomy or lumpectomy may be different

Research Objectives To evaluate rates of bilateral mastectomy in a racially/ethnically diverse, population based sample of recently diagnosed breast cancer patients To compare factors associated with receipt of bilateral mastectomy to unilateral mastectomy and lumpectomy

Study Sample All women age < 79 with ductal carcinoma in situ (DCIS) and a 20% random sample of those with invasive cancer reported to the Detroit and Los Angeles SEER registries in 2002 Surveyed a mean of 9 months post-diagnosis 2,647 accrued, 2,382 eligible, 1,844 responded (RR=77.4%) Survey data merged to SEER data

Measures Primary outcome: type of surgery received obtained from patient self-report –Any mastectomy vs. lumpectomy –Bilateral vs. unilateral mastectomy Independent variables –Patient demographics (age, race, education, marital status) –1 st degree family history –Tumor stage

Patient Attitudes Toward Surgery When decisions were being made about your surgery, how important was it to you that the type of surgery you had: RecurrenceBody Image Would keep you from worrying about the cancer coming back Would not make you feel bad about your body Would allow you to avoid a 2 nd surgery Would not interfere with your sex life Would reduce the chance of cancer coming back Would allow you to feel feminine

Analytic Methods Descriptive statistics across all variables Chi-square and t-tests used to examine differences in surgery received and independent variables Two-part logistic regression model: –Any mastectomy vs. lumpectomy –Bilateral vs. unilateral mastectomy

Sample Characteristics (N=1,844) %, mean Mean age60 Married/partnered58 Race White AA Latina/other Education H.S. graduate or less Some college or more st degree family history9 Stage 0 I II III

Patient attitudes toward surgery

Overall rates of surgery

Mastectomy-treated patients

Factors Associated with Surgery 0.75 ( ) ( ) 0.41 ( )** 1.30 ( ) ( ) 4.97 ( )* Stage 0 Stage I Stage II Stage III 2.76 ( ) 1.00 ( ) 6.77 ( ) 0.57 ( ) Patient attitudes Recurrence concerns Body image concerns 3.00 ( )1.10 ( )1 st degree family history 0.94 ( ) 1.58 ( ) 1.00 ( ) 1.16 ( ) Demographics Age White (vs. Non-white) Bilateral vs. unilateral mastectomy (N=646) Any mastectomy vs. lumpectomy (N=1,844) * Wald Chi-square=25.26, p=0.000 ** Wald Chi-square=1.83, p=0.607

Limitations Cross sectional survey Small absolute number of bilateral mastectomy May not be generalizable outside of Detroit or Los Angeles No information regarding patient use of genetic testing and/or genetic mutations

Summary Decision making for any mastectomy vs. lumpectomy is different from that for bilateral vs. unilateral mastectomy –The former is driven largely by stage and patient attitudes –The latter is associated with high risk for a new primary (younger age, white race, 1 st degree family history) –Patient concerns about recurrence appear to affect bilateral mastectomy decisions

Implications Further work to evaluate how and when women make bilateral mastectomy decisions is needed Providers need to be prepared to discuss bilateral mastectomy with patients Tools to help women understand the risks and benefits of bilateral mastectomy vs. other surgical options may be useful in decision making –Family history –Risk of recurrence

Thank you

CanSORT U of M Public Health Nancy Janz Medical School Steven Katz Sarah Hawley Jennifer Griggs Amy Alderman Reshma Jagsi Tim Hofer Chris Friese Arden Morris Samantha Hendren Chris Sonnenday David Miller Cancer Center American College Of Surgeons Connie Bura David Winchester Sloan-Kettering Monica Morrow UC Berkeley Mahasin Mujahid Rand Andy Dick

Patient report vs. SEER Patient report N SEER codesBilateral mastectomyUnilateral mastectomy Lumpectomy1053 Unilateral mastectomy25450 Double mastectomy372