Improved Local Control of Lung and Liver Tumors Associated with DoseEscalated Stereotactic Body Radi

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Improved Local Control of Lung and Liver Tumors
Associated with Dose-Escalated Stereotactic Body
Radiation Therapy (SBRT) Supports a Dose-Response
Relationship

• Robert McCammon MD, Tracey Schefter MD, Laurie
  Gaspar MD, Rebekkah Zaemisch, Daniel Gravdahl,
  and Brian Kavanagh MD
• Department of Radiation Oncology
• University of Colorado Cancer Center

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Background/Purpose
-Multiple prospective trials have established the
feasibility and safety of SBRT delivered to doses
as high as 60 Gy in 3 fractions to selected
tumors within the lungs or liver -While safety
data exists, little information is available
regarding the relationship between dose applied
and the resultant local control of treated
tumors -Additionally, prognostic factors for
local tumor control in the setting of SBRT are
not well-defined -We therefore analyzed the
records of patients treated consecutively at our
institution with SBRT to lung/liver or other
extra-CNS sites to determine prognostic factors
for local control, including SBRT dose applied
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Patients/Methods
-152 patients with 261 treated lesions were
identified, 18 of whom were treated on
prospective phase I/II trials -Local control was
assessed via routine follow-up, which included
serial imaging -Nominal dose and equivalent
uniform dose (EUD) were recorded for each
patient -Univariate and multivariate analyses
were performed to relate tumor local control to
nominal dose, EUD, gross tumor volume (GTV), and
additional patient/tumor factors
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Results
-Local control improved as dose increased,
expressed as either EUD or nominal dose -Tumors
treated to a nominal dose of ?54 Gy were
controlled in 90 of cases at 3 years
(actuarial) -On univariate analysis, lung
location and ltmedian GTV were also associated
with improved local control, but both lost
significance on multivariate analysis -Treatment
was generally well-tolerated with grade 3 or
higher toxicity in 3.4 of patients
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Conclusions
-This large single institution series suggests a
dose-response relationship within the range of
SBRT doses applied -Excellent local control is
achieved with a nominal dose of 54 Gy or higher,
corresponding to and EUD gt64.3 Gy -These results
support the use of aggressive SBRT regimens when
durable tumor control is the primary objective
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Local Control according to Dose