SABCS 2022 Takeaways - 12

12
POLAR FOR
PREDICTIVE
VALUE OF
RT BENEFIT
P
revious data established
that radiotherapy
reduces locoregional
recurrences (LRR) in all different
clinical subgroups, but there are no
clinically validated predictive biomarkers
for radiation therapy.
Per Karlsson, MD, and colleagues evaluated
the predictive potential of POLAR (Profile for
the Omission of Local Adjuvant Radiotherapy),
an investigational 16-gene molecular signature
that was developed based on gene expression
differences between patients with and without
local recurrence after breast-conserving
surgery. Genes included in the signature have
known roles in cellular proliferation and the
immune response.
T
he researchers performed
a meta-analysis of 623
patients with lymph nodenegative
/ER+/HER2- breast
cancer who were enrolled
in one of three randomized
clinical trials examining the
efficacy of breast-conserving
surgery with and without
local breast radiation therapy.
The clinical trials included in
the meta-analysis were the
Swedish SweBCG91RT trial,
the Scottish Conservation
Trial (SCT), and a trial from
the Princess Margaret
Hospital (PMH) in Canada.
Among the 623 patients in
the meta-analysis, 354 were
from SweBCG91RT, 137 from
SCT, and 132 from the PMH
trial.
" Looking at the combined
result of all of these three
trials we have a clear picture
of a high effect of radiotherapy
in the POLAR high
group, with a hazard ratio of
0.37 and almost no effect of
radiotherapy in the POLAR
low group, with a hazard
ratio of 0.92, " Dr. Karlsson
said during his presentation.
" Regarding the rates of
locoregional recurrences in
the no-radiotherapy arms:
among POLAR high patients
it was 20% at 10 years and
in POLAR low patients, it was
just 5%. So it's also clear
that POLAR is prognostic,
both in univariate and multivariable
analyses including
age, tumor size, grade, and
IHC subtypes. "
The interaction between
POLAR score and radiotherapy
was statistically significant
(HR, 0.64; 95% CI: 0.44-0.94;
p = 0.022).
LOOKING AHEAD
There are plans to move POLAR into prospective trials.
In Sweden and the Scandinavian countries, Dr. Karlsson
and colleagues are discussing a trial with and without
radiotherapy in regional disease. But the first step forward
for this assay in breast radiotherapy is for the researchers to
perform the analytical validation to establish a qPCR platform.
2022 SABCS TAKEAWAYS EDITION
Per Karlsson, MD

SABCS 2022 Takeaways

Table of Contents for the Digital Edition of SABCS 2022 Takeaways

SABCS 2022 Takeaways - A
SABCS 2022 Takeaways - 1
SABCS 2022 Takeaways - 2
SABCS 2022 Takeaways - 3
SABCS 2022 Takeaways - 4
SABCS 2022 Takeaways - 5
SABCS 2022 Takeaways - 6
SABCS 2022 Takeaways - 7
SABCS 2022 Takeaways - 8
SABCS 2022 Takeaways - 9
SABCS 2022 Takeaways - 10
SABCS 2022 Takeaways - 11
SABCS 2022 Takeaways - 12
SABCS 2022 Takeaways - 13
SABCS 2022 Takeaways - 14
SABCS 2022 Takeaways - 15
SABCS 2022 Takeaways - 16
SABCS 2022 Takeaways - 17
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