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

6077 General Poster Session (Board #6B), Mon, 1:15 PM-5:15 PM
Cost-effectiveness of biomarker-directed bevacizumab for first-line therapy
of persons with metastatic colorectal cancer. Presenting Author: Kristin
Berry, Fred Hutchinson Cancer Research Center, Seattle, WA
Background: When added to first-line chemotherapy for metastatic colorectal
cancer, bevacizumab provides a moderate survival increase, but is
associated with significant adverse events and high cost. As only a minority
of patients respond to antiangiogenic therapy, a diagnostic that identifies
potential responders ex ante could potentially change the benefit to risk
profile of bevacizumab and likely improve cost-effectiveness. Since efforts
to identify a predictive test have so far been unsuccessful, a novel strategy
may be to measure tumor response after bevacizumab treatment initiation
using an in vivo biomarker test to guide decisions on whether patients
should continue treatment. The objective is to estimate the costeffectiveness
of biomarker-directed use of bevacizumab in first-line treatment
of metastatic colorectal cancer compared to standard care. Methods:
The analysis takes the perspective of the US healthcare system. A decision
model was built to estimate the incremental effect of adding bevacizumab
to IFL, FOLFIRI, 5FU/LV and FOLOFOX/XELOX regimens. Survival data,
estimated through a meta-analysis of four clinical trials, combined with
utilities from the literature were used to calculate quality-adjusted life
years (QALYs). Costs were based on Medicare reimbursement and expert
opinion. Assumed performance characteristics of the biomarker technology
(sensitivity, specificity – provided by our industry partner) were 75% and
95% 10 days after commencement of bevacizumab. Results: The biomarkerdirected
bevacizumab strategy dominated usual care, providing both an
average per patient gain of 0.015 QALYs and a cost-savings of $21,038.
The cost-effectiveness of the biomarker technology was most influenced by
the cost of the test and colorectal cancer utilities. Variations in biomarker
specificity and sensitivity changed the magnitude of cost-savings and
benefit gain but did not change the overall result of dominance. Conclusions:
Modeling predicts that a validated marker which could identify responders
to bevacizumab will save money and improve quality-adjusted life years.
The results support additional investment in identifying such a diagnostic.
6079 General Poster Session (Board #6D), Mon, 1:15 PM-5:15 PM
Surveillance after potentially curative breast cancer treatment: The impact
of HMOs. Presenting Author: Robert J. Avino, Saint Louis University, St.
Louis , MO
Background: Over 230,000 new cases of breast cancer are diagnosed in the
US annually. Most patients receive curative-intent treatment. Posttreatment
surveillance is commonly done. We have previously documented
dramatic variation in surveillance intensity among ASCO experts. The only
surveillance modalities endorsed by ASCO for asymptomatic patients are
office visit and mammogram. It is commonly believed that health maintenance
organizations (HMOs) restrict test utilization. We sought to determine
the effect of HMO penetration rate on the known variation in
surveillance strategies. Methods: The 3245 ASCO members who indicated
that breast cancer was a major clinical focus of their practice were surveyed
regarding their surveillance practices. Members were asked to consider 4
idealized clinical vignettes and indicate their surveillance plan for each. A
menu of 12 testing modalities was offered. Practice patterns were stratified
by HMO penetration rate (0-14%, 14-22%, 22-33%, 33-61%) in each
physician’s practice location. Repeated-measures ANOVA was employed
for analysis. Results: Of the ASCO members surveyed, 1012 responded;
915 were evaluable. The modalities most frequently recommended were
office visit, CBC, liver function tests (LFTs), and diagnostic mammogram.
There was significant variation (p�0.05) in the recommended frequency of
utilization of diagnostic mammogram, but in no other modalities. For
example, in year 1, diagnostic mammogram was recommended 1.9 � 1.8
(mean �SD) times for the 0-14% penetration rate cohort and 1.5 � 1.1
times for the 14-22% cohort. Conclusions: We found little evidence that
HMOs restrict test utilization. The HMO penetration rate in the clinician’s
practice location cannot account for the overall variation we have documented
previously.
Health Services Research
401s
6078 General Poster Session (Board #6C), Mon, 1:15 PM-5:15 PM
Deviations from guideline-based therapy for febrile neutropenia in cancer
patients. Presenting Author: Jason D. Wright, Columbia University College
of Physicians and Surgeons, New York, NY
Background: Febrile neutropenia (FN) is a common cause of morbidity in
cancer patients. We examined guideline and non-guideline based care for
cancer patients hospitalized with FN and examined how treatment influenced
outcomes. Methods: The Perspective database was used to examine
the treatment of solid tumor patients with FN from 2000-2010. To capture
initial decision-making, we examined treatment within 48 hrs of admission.
Based on evidence-based guidelines we determined the appropriate
use of guideline-based antibiotics as well as use of treatments not routinely
recommended, vancomycin and granulocyte-colony stimulating factors
(GCSF). Hierarchical mixed effects models were developed to examine the
influence of patient, physician, and hospital characteristics on the quality
of treatment. Patients were stratified into low and high-risk groups and the
effect of initial treatment on outcome (nursing home discharge and death)
examined. Results: Among 25,231 patients with FN, within 48 hours of
admission blood cultures were obtained in 90%, guideline-based antibiotic
administered to 79%, vancomycin to 37%, and GCSF to 63%. Patients
treated at high-volume hospitals, by high-volume physicians and patients
managed by hospitalists were more likely to receive guideline-based
antibiotics (p�0.05). Vancomycin use increased with time from 17% in
2000 to 55% in 2010 while GCSF use only decreased from 73% to 55%.
Patients treated by internists and hospitalists were more likely to receive
vancomycin; high-volume physicians were less likely to treat with both
vancomycin and GCSF (p�0.05). Among patients who received GCSF,
15% received only one dose and 22% received 2 doses of filgrastim.
Among low-risk patients prompt initiation of guideline-based antibiotics
decreased the risk of discharge to a nursing facility (OR�0.78; 95% CI,
0.66-0.91) and death (OR�0.65; 95% CI, 0.50-0.85). Conclusions: There
is substantial variability in the initial treatment for FN in cancer patients.
While use of appropriate empiric antibiotics is high, use of non guidelinebased
treatments such as vancomycin and GCSF are common. Physician
and hospital factors are the most important predictors of both guideline and
non guideline-based treatment.
6080 General Poster Session (Board #6E), Mon, 1:15 PM-5:15 PM
The relationship between symptom burden and perceived comorbidity in
outpatients with common solid tumors. Presenting Author: Christine
Ritchie, Unviersity of California, San Francisco, San Francisco, CA
Background: Cancer patients have high symptom burden, but it is unclear
whether comorbid conditions are associated with patient-reported symptom
burden (the number and severity of symptoms). Methods: The Eastern
Cooperative Oncology Group (ECOG) enrolled 3106 patients with invasive
cancer of the breast, colon/rectum, prostate and lung, regardless of phase
of care or stage of disease. At baseline, patients completed the M.D.
Anderson Symptom Inventory (MDASI) and were also asked how bothered
they were by difficulties related to health problems other than cancer.
Symptom burden (SB) was defined as the number of symptoms scored 7 or
higher on the 13-item MDASI physical scale. Variance-weighted least
squares regression was used to identify factors associated with increasing
levels of being bothered by comorbid conditions. Results: About 65% of
patients were at least a little bothered by symptoms associated with
comorbidities. There was a strong association between increased bother by
comorbidities and increased SB (p�0.0001). Among those not bothered
by difficulties related to comorbidities, �1 symptom was rated 7 or worse
by 29% of patients, compared to 51% in patients bothered by difficulties
related to comorbidities (Fisher’s exact p�0.0001). Except for hair loss,
the severity of all symptoms was higher in those patients reporting bother
due to other perceived comorbidities. Factors associated with increased
bother include SB (p�0.0001), taking medications for diabetes
(p�0.0001), impaired ECOG performance status (p�0.03), older age
(p�0.004), and being perceived by the clinician as having higher degree of
difficulty for providing care (p�0.0001). Conclusions: Symptom burden
varies significantly according to the degree to which cancer patients
perceive bother that they attribute to comorbid health problems. Perception
of comorbidity is worth exploring as a stratification factor in symptom
research and as an indicator for complexity in patient care.
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