Postmastectomy radiotherapy for breast cancer

Abstract

BACKGROUND: Given accumulating evidence supporting postmastectomy radiotherapy (PMRT) in selected patients, it is important to evaluate patterns and correlates of PMRT utilization, including communication and attitudinal factors. METHODS: The authors surveyed 2382 patients diagnosed with breast cancer in 2002 and reported to the Los Angeles and Detroit Surveillance, Epidemiology, and End Results registries (n=1844, 77.4% response rate). Analyses were restricted to patients with nonmetastatic invasive breast cancer treated by mastectomy who had decided whether or not to undergo PMRT (n=396). The authors assessed rates of explanation, recommendation, and receipt of radiation by indication grouping, defined primarily by the 2001 American Society of Clinical Oncology guidelines. They evaluated correlates of PMRT receipt, including tumor and sociodemographic characteristics. They also explored patients' self-reported reasons for nonreceipt of PMRT. RESULTS: The adjusted proportion in each indication group reporting that a provider had explained radiation was high (77% of those in whom PMRT was indicated, 76% of those in whom medical opinion was divided, and 73% of those in whom PMRT was not indicated; P = .10). The adjusted proportions reporting recommendations for radiation (86%, 35%, and 17%, respectively) and receipt (81%, 34%, and 10%, respectively) varied significantly by indication grouping ( P < .001). On multivariate analysis, tumor size ( P < .001), lymph node status ( P < .001), comorbidity ( P = .02), and chemotherapy receipt ( P = .003) were found to be independent significant correlates of PMRT receipt. The most common reasons cited for not pursuing PMRT were lack of physician recommendation and perceived lack of need. CONCLUSIONS: PMRT receipt is strongly correlated with clinical indication. The authors found no sociodemographic disparities in utilization. However, approximately one-fifth of patients with strong indications did not receive treatment. Cancer 2009. © 2009 American Cancer Society. Peer Reviewed http://deepblue.lib.umich.edu/bitstream/2027.42/62035/1/24164_ftp.pdf

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Postmastectomy Radiotherapy for
Breast Cancer
Patterns, Correlates, Communication, and Insights Into the Decision Process
Reshma Jagsi, MD, DPhil1, Paul Abrahamse, MA2, Monica Morrow, MD3, Jennifer J. Griggs, MD, MPH2,
Kendra Schwartz, MD, MSPH4, and Steven J. Katz, MD, MPH5,6
BACKGROUND: Given accumulating evidence supporting postmastectomy radiotherapy (PMRT) in selected
patients, it is important to evaluate patterns and correlates of PMRT utilization, including communication
and attitudinal factors. METHODS: The authors surveyed 2382 patients diagnosed with breast cancer in 2002
and reported to the Los Angeles and Detroit Surveillance, Epidemiology, and End Results registries (n¼1844,
77.4% response rate). Analyses were restricted to patients with nonmetastatic invasive breast cancer treated by
mastectomy who had decided whether or not to undergo PMRT (n¼396). The authors assessed rates of expla-
nation, recommendation, and receipt of radiation by indication grouping, defined primarily by the 2001 Ameri-
can Society of Clinical Oncology guidelines. They evaluated correlates of PMRT receipt, including tumor and
sociodemographic characteristics. They also explored patients’ self-reported reasons for nonreceipt of PMRT.
RESULTS: The adjusted proportion in each indication group reporting that a provider had explained radiation
was high (77% of those in whom PMRT was indicated, 76% of those in whom medical opinion was divided, and
73% of those in whom PMRT was not indicated; P ¼ .10). The adjusted proportions reporting recommendations
for radiation (86%, 35%, and 17%, respectively) and receipt (81%, 34%, and 10%, respectively) varied significantly
by indication grouping (P < .001). On multivariate analysis, tumor size (P < .001), lymph node status (P < .001),
comorbidity (P ¼ .02), and chemotherapy receipt (P ¼ .003) were found to be independent significant correlates
of PMRT receipt. The most common reasons cited for not pursuing PMRT were lack of physician recommenda-
tion and perceived lack of need. CONCLUSIONS: PMRT receipt is strongly correlated with clinical indication. The
authors found no sociodemographic disparities in utilization. However, approximately one-fifth of patients with
strong indications did not receive treatment. Cancer 2009;115:1185–93. V
C 2009 American Cancer Society.
KEY WORDS: mastectomy, radiotherapy, breast neoplasms, guideline adherence, quality of healthcare.
The use of postmastectomy radiotherapy (PMRT) to improve the locoregional control of breast cancer
has been well established for many years.1,2Early studies failed to demonstrate a survival benefit for
PMRT, in part due to the use of techniques now considered to be outdated, which resulted in an increased
Received: July 18, 2008; Revised: October 6, 2008; Accepted: October 8, 2008
Published online: January 29, 2009, V
C 2009 American Cancer Society
DOI: 10.1002/cncr.24164, www.interscience.wiley.com
Corresponding author: Reshma Jagsi, MD, DPhil, Department of Radiation Oncology, University of Michigan, UHB2C490, SPC 5010, 1500 East
Medical Center Drive, Ann Arbor, MI 48109-5010; Fax: (734) 763-7370; rjagsi@mail.med.umich.edu
1Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan;2Department of Internal Medicine, University of Michigan, Ann
Arbor, Michigan;3Department of Surgery, Memorial Sloan-Kettering Cancer Center, New York, New York;4Department of Family Medicine and Pub-
lic Health Services, Wayne State University School of Medicine, Detroit, Michigan;5Departments of Medicine and Health Management and Policy,
University of Michigan, Ann Arbor, Michigan;6VA Center for Clinical Management Research, Health Services Research and Development and the
Ann Arbor VA Center for Practice Management, Ann Arbor, Michigan.
The collection of cancer incidence data used in this publication was supported by the California Department of Health Services as part of the state-
wide cancer reporting program mandated by California Health and Safety Code Section 103885. The ideas and opinions expressed herein are those
of the author, and no endorsement by the State of California, Department of Health Services is intended or should be inferred.
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incidence of latecardiac mortalitythatoffset any potential
survival benefit from improved cancer control.3,4In
1997, randomized trials demonstrated, for the first time,
an overall survival advantage from PMRT,5-7with benefit
observednotonlyamongpatientswith?4positivelymph
nodes but also those with 1 to 3 positive lymph nodes.
Nevertheless, because locoregional recurrence rates in
patients with 1 to 3 positive lymph nodes were higher in
these trials than typically observed in the US,8-10the
appropriate selection of patients for PMRT has remained
asubjectof debate.
In 2001, the American Society of Clinical Oncology
(ASCO) consensus statement concluded that PMRT
was ‘‘recommended’’ for patients with ?4 positive ax-
illary lymph nodes and ‘‘suggested’’ for patients with
T3 tumors with positive axillary lymph nodes and
patients with operable stage III tumors.11The ASCO
panel further concluded that there was insufficient evi-
dence to make recommendations or suggestions for
the routine use of PMRT in patients with T1 or T2
tumors with 1 to 3 positive lymph nodes, and physi-
cian opinion remained divided regarding the manage-
ment of these patients.12Similar guideline statements
were also issued by other prominent groups contem-
poraneously.13-15
A limited number of studies have evaluated the use
of PMRT since these guidelines were disseminated, and
these have been limited by restriction to the elderly
patients in the Surveillance, Epidemiology, and End
Results (SEER)-Medicare database16,17or to experiences
at centers of excellence that may not be representative of
patterns of care and outcomes among patients treated in
more diverse settings.18Furthermore, to our knowledge,
none have examined clinician-patient communication
factors that direct the use of therapy. To address these
limitations, we examined patterns and correlates of
PMRT use among a population-based sample of
patients diagnosed with breast cancer in 2002 and
reported to the SEER registries of Southern California
and Detroit. We asked the following questions: 1)
Did patients with clear indications for PMRT receive
it? 2) How frequently was PMRT used in patients for
whom medical opinion was divided? 3) Were there
sociodemographic differences in utilization? 4) What
communication and patient attitude factors influenced
receipt of treatment?
MATERIALS AND METHODS
Study Population and Sampling
Details of the sampling strategy have been reported else-
where.19Women aged ?79 years who were diagnosed
with breast cancer and identified by the SEER Cancer
Registries of the greater metropolitan areas of Detroit and
Los Angeles during a 14-month period from December
2001 through January 2003 were eligible. The prelimi-
nary study sample (n¼2647) was accrued monthly dur-
ing the study period. The sample included all patients
with ductal carcinoma in situ. In addition, all African
American women with invasive disease and a random
sample of non–African American women with invasive
disease were selected. A random number generator was
used by field staff to select the non–African American
invasive cases. Of the preliminary sample, 90% were eligi-
ble for the study (n¼2382). The study protocol was
approvedby the institutionalreview boardsof the Univer-
sity of Michigan, the University of Southern California,
and WayneState University.
The survey was completed by 77.4% of eligible
women (n¼1844). SEER data were merged with survey
data for 98.2% of patients. For this study of PMRT, we
selected patients with invasive disease (stage I-III) who
received mastectomy (n¼447).
Measures
Copies of the full questionnaire are available to interested
readers upon request to the corresponding author. The
dependent variable was self-reported receipt of PMRT
(‘‘finished,’’ ‘‘started,’’ or ‘‘going to start’’). Independent
variables included tumor characteristics (tumor size,
lymph node stage, grade, hormone receptor status),
patient characteristics (age, race, income, education, in-
surance status, comorbidities), and other characteristics
(distance to radiotherapy [RT] facility, chemotherapy
receipt). Information regarding tumor characteristics was
based exclusively on SEER data; information regarding
patient and other characteristics was drawn from self-
report. For age and race/ethnicity, SEER data were used
forthefew patientsmissingdataby self-report.
We assessed rates of explanation, recommendation,
and receipt of radiation by indication categories, defined
primarily by reference to the ASCO guidelines that were
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published immediately before the period in which these
patients were treated. We considered ‘‘RT indicated’’ for
patients with any T classification and N2 or N3 disease,
those with T3, lymph node–positive tumors, and those
with T4 tumors of any lymph node stage. We considered
‘‘RT not indicated’’ for patients with T1-2N0 tumors
(recognizing that the lack of margin information would
lead to the utilization of RT in a small proportion of
patients in this group whose mastectomies did not yield
negative margins and therefore restricting our analysis to
consider underuse rather than overuse). We considered
‘‘opinion divided’’ for patients with T1-2, N1 disease and
those withT3N0disease.
Patients who did not receive or plan to receive radia-
tion were asked to indicate the reasons for this decision.
Patient attitudes were also ascertained by asking women
who perceived a choice of surgical treatment options the
following question: ‘‘When you were deciding between
mastectomy and lumpectomy, how much was your deci-
sion influenced by whether the treatment you chose...’’
From the 23 items that followed, we conducted factor
analyses and subsequently constructed a number of scales,
1 of which addressed attitudes toward radiation and is
considered in this analysis (3 items: ‘‘would allow you to
avoid exposing yourself to radiation’’; ‘‘would allow you
to avoid the side effects of radiation therapy’’; and ‘‘would
allow you not to have to go back and forth to radiation
treatment every day for weeks’’; alpha ¼ .95). Summary
scores were interval measures that ranged from 1 (not
influenced by attitude factor) to 4 (greatly influenced by
attitude factor). We collapsed the score into 2 categories:
not influenced or slightly influenced (scores from 1 to
2.3) and moderately to greatly influenced (scores from 2.4
to 4.0).
Statistical Analysis
We calculated proportions of patients who received
PMRT by tumor, patient, and other characteristics. Uni-
variate analysis was performed using chi-square testing. A
multivariate logistic regression model of PMRT receipt
was constructed with a backward stepwise approach, with
tumor, patient, and other characteristics as independent
variables.Werepeatedtheseanalysesafter includingasep-
arate category indicating a missing value for variables with
>5% missing data (tumor size, tumor grade, age, educa-
tion, income, and chemotherapy receipt). These second-
ary analyses yielded the same results. To examine the
association between patient radiation attitude score and
PMRT receipt, we regressed receipt of PMRT on the atti-
tude toward RT scale, controlling for clinical and predis-
posing factors to calculate adjusted proportions, and
testing for significance using Wald tests. All analyses were
evaluated for second-order interactions between selected
covariates, and none were observed. Point estimates were
adjusted for design effects by using a sample weight that
accounted for differential selection by stage, ethnicity,
and nonresponse.
RESULTS
Sample Characteristics
Ten patients who reported that they were still considering
whether to have radiation at the time of the survey were
excluded, as were 41 patients not providing a response to
the item asking whether they were considering RT, result-
ing in a sample size of 396 patients. Table 1 shows the
characteristics of the 148 patients who reported having
finished, started, or planned to start RT (hereinafter
described as ‘‘receiving PMRT’’) and the 248 patients
whoreportedtheywerenot considering radiation.
The median patient age was 59 years; 193 (48.7%)
had lymph node–negative disease (11 of whom were stage
T3N0 and 7 of whom were T4N0), 104 (26.3%) had N1
lymph node disease (14 of whom were T3N1 and 4 of
whom were T4N1), 45 (11.4%) had N2 disease, and 23
(5.8%) had N3 disease. Fifteen patients had Nx disease,
and lymph node status was unknown in another 16
patients. Overall, 175 patients (44.2%) were classified in
the ‘‘RT not indicated’’ group, 97 (24.5%) were in the
‘‘opinion divided’’ group, and 99 (25.0%) were in the
‘‘RTindicated’’group.
Factors Correlated With PMRT Receipt
On univariate analysis, tumor factors of T classification,
N classification, and histologic grade were all found to be
significantly associated with the receipt of PMRT, as was
the receipt of chemotherapy. Young age, black race, and
lack of insurance were also significantly associated
with PMRT, but other demographic variables were not
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Table 1. Univariate Correlates of Radiation Receipt After Mastectomy
CharacteristicNo. of Patients* PMRT, %P
T classification
T1
T2
T3
T4
<.001
175
122
43
32
18.9
38.5
81.4
78.1
N classification
N0
N1
N2
N3
Nx
<.001
193
104
45
23
15
17.1
42.3
86.7
82.6
46.7
Tumor grade
Low
Intermediate
High
.01
59
130
154
23.7
32.3
46.0
Age, y
<40
40-49
50-59
60-69
701
.003
29
65
95
93
62
62.1
41.5
42.1
29.0
24.2
No. of comorbidities
0
‡1
.02
193
203
43.0
32.0
Race
White
African American
Other (includes Asian,
Native American, other)
<.001
247
103
43
31.2
39.9
62.8
Insurance
None
Medicaid
Medicare
Private
Other
.001
9
17
124
150
85
77.8
64.7
28.2
34.7
44.7
Marital status
Married or partnered
Not married
.28
220
176
35.0
40.3
Education
Some high school or less
High school graduate
Some college or technical school
College graduate and beyond
.38
50
77
142
82
48.0
36.4
35.2
34.2
Income
<30,000
30,000-69,999
70,0001
.08
139
100
75
42.5
29.0
32.0
Received chemotherapy
Yes
No
<.001
225
118
51.6
9.3
PMRT indicates postmastectomy radiotherapy.
*Numbers may sum to <396 due to missing values. The P values tested differences in the receipt of radiation for the
selected variable.
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(Table 1). Patients with comorbidities were less likely to
receive RT. On multivariate analysis, only tumor size
(P < .001), lymph node status (P < .001), comorbidity (P
¼ .02), and chemotherapy receipt (P ¼ .003) were found
tobeindependentsignificantcorrelatesofPMRTreceipt.
Figure 1 shows the proportions of patients who
reportedreceivingexplanationsofradiation,receivingrec-
ommendations for radiation, and receiving radiation, by
indication category and adjusted for clinical and socioeco-
nomic factors. Similar proportions in each indication
group reported receiving an explanation of radiation from
their surgeon or another healthcare provider (P ¼ .17);
the proportions reporting recommendations for radiation
and receipt of PMRT varied substantially by indication
grouping (P < .001). Physician recommendation was
strongly correlated with PMRT receipt; 80.2% of those
reporting that a surgeon or other provider had recom-
mended RT received PMRT, whereas only 3.4% report-
ingno recommendation receivedPMRT(P< .001).
Attitudes Toward Radiation and Reasons
for Declining PMRT
As shown in Table 2, few patients with strong indications
for RT were not considering PMRT. Of note, the most
common reason cited by those in this group for not con-
sidering RT was the lack of a physician recommendation.
As expected, the majority of T1 or T2, N0 patients were
not considering RT, and the most common reasons cited
were that ‘‘there was no need’’ and that ‘‘my physician did
not recommend it.’’ Among patients in whom medical
opinionwasdivided(T3N0orT1-2,N1disease),approx-
imately the same proportion of patients were not consid-
ering PMRT as those who were definitely undergoing
PMRT. Again, the most common reasons cited for not
pursuing PMRT in this group were lack of physician rec-
ommendation and a perceived lack of need. Few patients
reported that concerns about side effects or inconvenience
played a role, and similarly few reported that they per-
ceived they could not have RT for medical reasons. Con-
cernaboutcostwas reportedbyonly1 patient.
Figure 2 shows the association of patients’ concerns
about RT with receipt of PMRT. Overall, 34% of the
mastectomy patients reported concerns about radiation.
Frequencyofmoderateto significantconcernaboutradia-
tion varied by indication grouping; 14% of those for
whom PMRT was indicated, 28% of those for whom
medical opinion was divided, and 50% of those for whom
PMRT was not indicated (P < .001). Figure 2 shows that
among all patients, those patients who were most con-
cerned about radiation were less likely to receive radiation
ineach indicationgrouping(P< .001).
DISCUSSION
This population-based study of patients who were diag-
nosed with breast cancer in 2002 in 2 large metropolitan
areas and treated with mastectomy reveals that most
patients with guideline-based indications for PMRT
receive it. As one would hope, the tumor characteristics
(primary tumor size and lymph node status) that define
indications for PMRT treatment were found to be highly
correlated with PMRT receipt, and patients without
comorbidities were more likely to receive PMRT. Chem-
otherapy receipt was also found to be independently cor-
related with radiation receipt. Nonclinical factors
appeared to be less important. We did not observe signifi-
cant differences in receipt of treatment by socioeconomic
or racial groups after controlling for clinical factors.
Nevertheless, it was concerning that approximately one-
fifth of patients with strong indications for treatment did
not receive RT, and approximately one-fifth of patients in
each indication category reported that their providers had
neverexplainedRTto them.
Few previous studies have addressed PMRT utiliza-
tion. A 2002 survey of radiation oncologists found strong
consensus regarding the need for PMRT in patients with
FIGURE 1. This figure demonstrates the rates with which
patients reported that radiotherapy (RT) was explained (P ¼
.10), recommended (P < .001), and received (P < .001) by in-
dication grouping. Rates were adjusted for age, race, educa-
tion, marital status, and comorbidities.
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?4 involved lymph nodes but divided opinion regarding
the management of N1 disease.12Although this study was
valuable in illuminating radiation oncologists’ attitudes,
toourknowledgeactualpatternsofutilizationandreasons
for nonutilization were not addressed. Further studies
have therefore been necessary to explore whether PMRT
utilization complies with consensus guidelines and radia-
tion oncologists’ opinions (which may differ from those
of surgeons,whoserve asgatekeepersinthesecases).
A large study using the SEER-Medicare database
explored utilization of PMRT in women aged ?65 years
who were treated with mastectomy between 1991 and
1999.16The study documented temporal trends toward
increasedutilizationafterthepublicationoftheinfluential
Danish and Canadian trials. It also documented differen-
ces between teaching and nonteaching institutions, as well
as associations between PMRT use and patient age, race,
distance to nearest RT facility, region of the country, soci-
oeconomicstatus,comorbidity,and tumorcharacteristics.
Receipt of PMRT ranged from only 30% to 50% among
elderly patients with ?4 positive lymph nodes who were
treated in this period, during which clinical trial informa-
tion wasaccumulatingand national guidelines hadnot yet
been promulgated. Although innovative, the study was
limited by likely underreporting of radiation treatment in
SEER, the necessity of relying upon proxy measures of
socioeconomic status based upon zip code and census
tract information, the omission of nonelderly patients,
and the fact that the observation period preceded the
releaseofclinical guidelines.
A subsequent study considering SEER-Medicare
data through 2002 found that the rate of PMRT for
patients with high-risk (defined by the authors as T3 or
T4 or N2 or N3) disease stabilized after 1997, and from
1998 to 2002, only 53% of high-risk elderly patients
received PMRT.17In contrast, a study examining guide-
line concordance in the treatment of womenat 8 National
Comprehensive Cancer Network (NCCN) member
institutions from 1997 to 2002 found high concordance
with treatment guidelines (83.6% of those in whom
PMRT was recommended by the NCCN guidelines
received it, and 38.6% of those in whom it should be con-
sidered received it).18In the ‘‘consider RT’’ group, the
investigators found correlations with institution, tumor
characteristics, age, and receipt of chemotherapy.
Although the NCCN study is strengthened by including
Table 2. Patient Reasons for Not Considering PMRT, by Indication Grouping
RT Not IndicatedOpinion DividedRT Indicated
Total
No. not considering RT
No. not considering RT and indicating reasons
175
152
138
97
60
49
99
20
17
Reasons
My doctor(s) did not recommend it
There was no need
It was too inconvenient
I was worried about side effects or complications
I did not think it would be helpful
I was worried that it would cost too much
I did not know about it
I could not have it for medical reasons
57.3%
54.4%
4.4%
6.5%
5.8%
0.7%
0.0%
4.4%
69.4%
42.9%
2.0%
6.1%
4.1%
0.0%
0.0%
6.1%
52.9%
23.5%
0.0%
11.8%
17.7%
0.0%
0.0%
5.9%
PMRT indicates postmastectomy radiotherapy; RT, radiotherapy.
FIGURE 2. This figure demonstrates rates of receipt of post-
mastectomy radiotherapy (RT) by indication grouping and
concern regarding radiation effects. Rates were adjusted for
age, race, education, marital status, and comorbidities (P <
.001). *Indicates the number of patients in each cell.
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women of all ages, it may not be generalizable to the
broader population of patients not treated at elite
institutions.
Thus, the current study complements this previous
work. Our findings suggest that PMRT utilization among
patients with guideline-based indications in a population-
based sample was higher than in studies focusing on el-
derly patients alone and very similar to that observed
among patients at elite medical centers. As one would
hope, PMRT receipt was highest among patients with
advanced lymph node status and large primary tumors.
This may reflect the impact of the 2001 ASCO consensus
statement or general acceptance of the need for PMRT in
patients with advanceddisease. The finding that receipt of
chemotherapy was an independent predictor of PMRT
receipt may indicate that some patients or their physicians
are more inclined toward aggressive treatment or perceive
greater recurrence risks, potentially due to unmeasured
differences in tumor characteristics, physician-patient
interactions,orother factors.
This study also offers insights into patients’ decision
processesregarding PMRT, including information
regarding patient perceptions of provider discussions and
recommendations, as well as reasons they did not receive
PMRT.Itisreassuringthatpatientsdidnotappeartoper-
ceive cost or inconvenience to be important barriers to
receiving PMRT. On the other hand, those who scored
highest on the scale assessing general concerns about radi-
ation were less likely to receive RT in each indication
grouping—although this was observed least frequently for
patients with guideline-based indications for treatment.
Because patients undergoing mastectomy may have
selected their surgery out of a desire to avoid RT and are
more likely to express major concerns about radiation
than patients undergoing lumpectomy,19it is particularly
important to ensure that adequate explanations of the na-
ture of RT and its side effects are provided to patients
with any indications for considering treatment. Of note,
although we found that most patients in all risk groups
reported that a provider had explained RT, this explana-
tion of radiation may have been in the setting of discus-
sion of initial therapeutic options, including breast
conservation (and not necessarily a specific discussion of
PMRT). Our finding that those with the strongest indica-
tions for PMRT were least concerned about radiation
may indicate that discussions specifically focused on a rec-
ommendation for PMRT reassure patients regarding the
risks ofthismodalityof treatment.
Several aspects of the study merit comment. We
note several strengths, including the diverse population-
based sample derived from 2 large urban areas of the US:
high response rates, valid measures of treatment use,
patient-level clinical and sociodemographic variables, and
patient report of clinician-patient communication. How-
ever, the study has several limitations. First, the fact that
the population-based sample was drawn from 2 geo-
graphicareas(DetroitandLosAngeles)maylimitthegen-
eralizability of our findings to other areas, such as rural
regions. The modest number of patients undergoing mas-
tectomyinthisstudymayhavelimitedthepowertodetect
theeffectofcertain variablesonpatternsofPMRTutiliza-
tion. Missing data for certain variables may also have
affected the results. Patient report of discussions with
clinicians may be subject to recall bias. In particular, we
did not distinguish between discussions of RT in the con-
text of breast conservation before the final surgical deci-
sion versus specific discussion of PMRT. Thus, a higher
proportion of patients may not have appreciated the ra-
tionale for PMRT or actively participated in the decision
to forgo this treatment than indicated by our findings
regarding radiation explanation. Finally, timing of sys-
temic therapywithrespectto surgerywasnotknown.
Our findings have important implications for clini-
cal care. A nontrivial proportion of patients with clear
indications for treatment (19%) did not receive PMRT.
In addition, approximately one-fifth of patients studied
reported that no provider ever explained RT to them.
Increasing surgeons’ awareness of the importance of
explaining the rationale for PMRT to their patients
undergoing mastectomy, even in cases in which opinion is
dividedand the individualsurgeonmight not recommend
treatment,is critical.These patients may nevertheless ben-
efit from consultation with a radiation oncologist, so that
they may participate actively in this important treatment
decision.
As increasing evidence accumulates to support the
use of PMRT in selected patients and to help select those
patients whom PMRT is most likely to benefit,20-23it
becomes even more important to investigate its utiliza-
tion. Future research should continue to track trends in
the utilization of PMRT in the face of an evolving evi-
dence base and clinical guidelines. Indeed, as Punglia
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et al. have suggested, receipt of PMRT may be a useful in-
dicator of the quality of healthcare, just as postlumpec-
tomy RT is.16Correlations between PMRT utilization
and surgeon characteristics, including practice factors,
may be ofparticularinterest.Future studiesshould seek to
assess patients’ understanding of the risks and benefits of
PMRT, the amount of time spent discussing PMRT with
their surgeons, which patients are referred to have further
discussion with radiation oncologists, and whether greater
involvement in the PMRT decision is desired by patients
or correlated with satisfaction. In this way, we may gain a
muchneededunderstandingofthequalityofpatient-phy-
sician communication in the setting of this complex
decision.
Conflict of Interest Disclosures
Funded by a grant from the National Cancer Institute (RO1
CA8837) to the University of Michigan.
Dr. Katz was supported by an Established Investigator Award in
Cancer Prevention, Control, Behavioral, and Population Sciences
from the National Cancer Institute (K05 CA111340).
This project has been funded in part with Federal funds from
the National Cancer Institute, National Institutes of Health,
Department of Health and Human Services, under Contract
No. N01-PC-35,139 and NO1-PC-65,064.
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