Annual Meeting Proceedings Part 1 - American Society of Clinical ...

56s Breast Cancer—Triple-Negative/Cytotoxics/Local Therapy
1028 Poster Discussion Session (Board #20), Mon, 1:15 PM-5:15 PM and
4:45 PM-5:45 PM
Are mastectomy rates really increasing? Experiences from a single institution
and a population-based database. Presenting Author: Min Yi, University
of Texas M. D. Anderson Cancer Center, Houston, TX
Background: Recent studies have reported increased mastectomy rates for
the treatment of early stage breast cancer during the last decade. The aims
of this study were to examine trends in mastectomy rates at a single
institution and in a population-based database and to compare differences
between the two cohorts. Methods: Patients with stage 0-II breast cancer
diagnosed from 2000 to 2008 were identified from our cancer center
institutional database (CC cohort, n�8,915) and the Surveillance, Epidemiology
and End Results database (SEER cohort, n�359,572). Patients
without primary surgery or unknown surgery type were excluded. Mastectomy
rates by the year of diagnosis were evaluated and multivariable
logistic regression models were built to identify clinicopathologic factors
that predicted mastectomy as the treatment choice. Results: The proportion
of patients treated with mastectomy decreased from 44.5% to 37.8%
between 2000 and 2005 in the CC cohort (P�0.003) and from 42.8% to
36.6% in the SEER cohort (P�0.0001). Subsequently, the mastectomy
rate increased to 48.6% in the CC cohort (P�0.0001) and to 40.1% in the
SEER cohort by 2008 (P�0.0001). Multivariable analysis found that
patients with younger age (�50), stage 0 or II cancer vs. stage I, high grade
tumor, low median household income, and lobular histology were more
likely to choose mastectomy in both the SEER and CC cohorts. In the CC
cohort, patients with preoperative breast MRI were also more likely to
undergo mastectomy. The percentages of patients receiving preoperative
MRI and choosing prophylactic contralateral mastectomy increased each
year in the CC cohort. The rate of preoperative breast MRI increased from
4.7% in 2005 to 9.6% in 2008 (P�0.0001). Patients choosing prophylactic
contralateral mastectomy increased from 8.4% in 2005 to 11.8% in
2008 (P�0.06). Conclusions: Our study shows that there was a decrease in
mastectomy rates from 2000 to 2005 and a subsequent increase in
mastectomy rates from 2005-2008 in both the CC and SEER cohorts.
Increased use of preoperative breast MRI and the decision to undergo
contralateral prophylactic mastectomy likely contributed to the increased
mastectomy rates in the CC cohort.
1030 Poster Discussion Session (Board #22), Mon, 1:15 PM-5:15 PM and
4:45 PM-5:45 PM
Short-term complications and use of breast brachytherapy in the national
Medicare population in 2008-2009. Presenting Author: Carolyn J. Presley,
Yale New Haven Hospital, New Haven, CT
Background: Brachytherapy as an alternative to whole-breast irradiation
(WBI) for early-stage breast cancer has disseminated into clinical practice;
however, current national treatment patterns and associated complications
remain unknown. Methods: We constructed a national sample of Medicare
beneficiares aged 66 to 94 who underwent breast conserving surgery in
2008-2009 and who were treated with brachytherapy or WBI. We used
hospital referral regions to assess national treatment variation and an
instrumental variable analysis to compare complication rates between
treatment groups, adjusting for patient and clinical characteristics such as
age, number of comorbidities, receipt of chemotherapy or screening
mammogram, and type of radiation facility. We compared one-year overall,
wound and skin, and deep tissue and bone complications between
brachytherapy and WBI using specific procedure and diagnosis codes
identified in Medicare claims. Results: Of the 29,648 women in our sample,
4,671 (15.8%) received brachytherapy. The median percent of patients
receiving brachytherapy varied substantially across hospital referral regions
(interquartile range: 7.5%-23.3%). In the bivariate analysis, 34.3% of
women treated with brachytherapy had a complication compared to 27.3%
of those who received WBI (P�0.001). After adjusting for patient and
clinical characteristics, 35.3% (95% CI: 34.7, 35.8) of women treated
with brachytherapy had a complication compared to 18.7% (95% CI:
18.2,19.2) treated with WBI (average predicted difference: 16.5%, 95%
CI: 15.8, 17.3, P�0.001). While brachytherapy was associated with a
16.9% (95% CI: 10.0, 23.8, P�0.001) higher absolute percentage of
wound and skin complications compared to WBI, there was no difference in
deep tissue and bone complications. Conclusions: Brachytherapy is commonly
used among Medicare beneficiaries; in some regions nearly one in
four women who underwent adjuvant radiation received brachytherapy.
After one year, wound and skin complications were significantly more
common among women who received brachytherapy compared to those
receiving WBI, but there was no difference in deep tissue and bone
complications.
1029 Poster Discussion Session (Board #21), Mon, 1:15 PM-5:15 PM and
4:45 PM-5:45 PM
Breast cancer multifocality-multicentricity and locoregional recurrance.
Presenting Author: Xiudong Lei, University of Texas M. D. Anderson Cancer
Center, Houston, TX
Background: The impact of multifocality (MF) and multicentricity (MC) on
locoregional (LR) control for invasive breast cancer, and the optimal local
treatment strategy for these tumors, is unknown. In particular, there is
disagreement in the literature regarding the use of Breast Conservation
Therapy (BCT). We evaluated a large single institution cohort of MF and MC
breast cancers to determine if they had inferior LR control rate when
compared to their unifocal counterparts. Methods: MF and MC were defined
pathologically as more than one lesion in the same quadrant and more than
one lesion in separate quadrants, respectively. Patients were categorized by
presence or absence of MF or MC disease and by the LR treatment modality
received – BCT (n�256), mastectomy alone (n�466), or mastectomy plus
post-mastectomy radiation therapy (n�184). 10 patients who underwent
BCT for MC disease against physician advice were excluded. MF and MC
tumors were analyzed both as a group and as separate entities. Kaplan-
Meier product limit method was used to calculate 5-year LR control rate.
Cox proportional hazards models were fit to determine independent
associations of MF/MC disease with LR control. Results: Median follow up
was 52 months. Out of 3722 patients with stage I-III disease who did not
receive neoadjuvant chemotherapy, 906 (24%) had MF (n�673) or MC
(n�233) disease. 5-year rate of LR control rate was 99% in the MF group,
96% in the MC group, and 98% in the unifocal group, (P � 0.44). Subset
analysis revealed no statistical difference in LR control regardless of the
type of LR treatment, (P � 0.67 in the BCT group, P � 0.37 in the
mastectomy alone group, and P � 0.29 in the mastectomy plus postmastectomy
radiation therapy group). There were 21 in-breast recurrences
after BCT (8.2%). After controlling for other risk factors, MF and MC did not
have an independent impact on LR control rate. Conclusions: MF and MC
disease are not independent risk factors for LR recurrence. Patients with
MF and MC breast cancer had similar rates of LR control to their unifocal
counterparts, regardless of LR treatment modality. Our data suggest that
BCT is a safe option for patients with MF tumors and that MF or MC disease
alone is not an indication for post-mastectomy radiation therapy.
1031 Poster Discussion Session (Board #23), Mon, 1:15 PM-5:15 PM and
4:45 PM-5:45 PM
Trends in the use of breast-conserving surgery and adjuvant radiation
therapy in patients with DCIS: A U.S. population-based analysis from 1996
to 2007. Presenting Author: Jennifer Nishimura, Case Western Reserve
School of Medicine, Cleveland, OH
Background: The treatment for patients with DCIS remains controversial.
Current guidelines based upon best available evidence suggest that breast
conserving surgery (BCS) followed by adjuvant radiation therapy (RT) result
in acceptable local control and breast cancer specific survival. The purpose
of this study was to analyze trends in patterns of care as well as identify
factors associated with surgery type and use of adjuvant radiation therapy
in a select cohort of patients enrolled into the SEER database. Methods: The
study included females 18 years and older with focal DCIS and known
tumor size of 5 cm or less diagnosed between 1996 and 2007. The
Cochran-Armitage trend test was applied to identify trends in the use of
BCS and RT over time. Multivariate logistic regression analyses were used
to determine factors associated with receiving BCS vs. mastectomy and
BCS plus RT vs. BCS alone. Cox proportional hazard model was used to
determine associations with breast cancer-specific mortality. Results: Of
the 34,233 women with DCIS, 76.59% were treated with BCS. 66.36% of
BCS patients received adjuvant RT over the study period. The proportion of
women receiving BCS increased from 71.5% in 1996 to 76.9% in 2007
(p�0.0001). Additionally, the proportion of women who underwent BCS
and received adjuvant radiation therapy over the same time period
increased from 55.3% to 69.7% (p�0.0001). Multivariate analysis
demonstrated that year of diagnosis, race, marital status, geographic
region, tumor size, tumor grade and comedo necrosis all were significantly
associated with the use of adjuvant radiation therapy, but age was not. Cox
proportional hazards models did not associate either surgery type or use of
adjuvant radiation in patients undergoing BCS with breast cancer-specific
mortality. Conclusions: Based upon reporting within the SEER database,
the proportion of DCIS patients undergoing BCS and the BCS patients
receiving adjuvant radiation increased over the study time period. Surgery
type and use of adjuvant radiation therapy in patients with BCS was not
associated with decreased risk of breast-cancer specific death in this
cohort.
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