Factors Associated with Bilateral vs. Unilateral Mastectomy in a Diverse, Population-based Sample of Breast Cancer Patients

Sarah T. Hawley, PhD, MPHUniversity of MichiganAnn Arbor VA Medical Center

AcknowledgementsAmy Alderman, MD

Reshma Jagsi, MD, DPhilJennifer Griggs, MD, MPH

Nancy Janz PhDAnn Hamilton, PhD

John Graff, PhDSteven Katz, MD

University of MichiganAnn Arbor VA Medical Center

Los Angeles and Detroit Metropolitan Area SEER RegistriesUniversity 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)– 1st 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:

Recurrence Body 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 2nd 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 age 60

Married/partnered 58

RaceWhiteAALatina/other

701812

EducationH.S. graduate or lessSome college or more

3664

1st degree family history 9

Stage 0IIIIII

3732229

Patient attitudes toward surgery

0

10

20

30

40

50

60

70

80

90

100

Recurrence Body image

Very important

Somewhat important

Not important

Overall rates of surgery

65

35

0

10

20

30

40

50

60

70

Any mastectomy (N=646) Lumpectomy (N=1198)

Mastectomy-treated patients

87

13

0

10

20

30

40

50

60

70

80

90

100

Bilateral mastectomy (n=84) Unilateral mastectomy (n=562)

Factors Associated with Surgery

0.75 (0.35-1.63)1.000.89 (0.37-2.16)0.41 (0.10-1.62)**

1.30 (0.84-2.01)1.001.87 (1.18-2.95)4.97 (2.51-9.83)*

Stage 0Stage IStage IIStage III

2.76 (1.14-6.68)1.00 (0.50-2.01)

6.77 (4.67-9.82)0.57 (0.38-0.84)

Patient attitudesRecurrence concernsBody image concerns

3.00 (1.36-3.61)1.10 (0.61-1.18)1st degree family history

0.94 (0.92-0.97)1.58 (1.20-1.86)

1.00 (0.99-1.02)1.16 (0.84-1.61)

DemographicsAgeWhite (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, 1st 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 www.cansort.org

USCAnn Hamilton

Dennis Deapen

Wayne StateJohn Graff

Kendra Schwartz

U of MPublic Health

Nancy Janz

Medical SchoolSteven Katz

Sarah Hawley Jennifer GriggsAmy AldermanReshma Jagsi

Tim Hofer Chris FrieseArden Morris

Samantha HendrenChris Sonnenday

David Miller

Cancer Center American CollegeOf Surgeons

Connie BuraDavid Winchester

Sloan-KetteringMonica Morrow

UC BerkeleyMahasin Mujahid

RandAndy Dick

Patient report vs. SEER

Patient reportN

SEER codes Bilateral mastectomy

Unilateral mastectomy

Lumpectomy 10 53

Unilateral mastectomy

25 450

Double mastectomy 37 2