2024-SABCS-Takeaways - 12

RADIATION ONCOLOGY CONTINUED
Research Roundup
Read on for key takeaways about studies
featured in presentations at the 2024
SABCS®. For more details, click on the
linked trial names. Session recordings
will be available on demand for registered
attendees through March 31, 2025.
A planned interim
analysis of the phase
III EUROPA trial (GS201)
of ET compared to
RT as single-modality
treatments suggested
that RT might better
preserve healthrelated
quality of life
in older women with
low-risk early breast
cancer compared to
ET. EUROPA directly
compared postoperative
RT to adjuvant ET in
women ≥ 70 years with
luminal-like early breast
cancer following breastconserving
surgery.
Of those patients
randomly assigned
to RT, approximately
85% received partialbreast
irradiation. At 24
months, more than 22%
of patients switched ET
due to adverse events,
and more than 12%
discontinued ET due to
toxicity. There was no
significant difference
in oncologic outcomes
between the ET and
RT arms at 24 months,
but RT was better
tolerated. Final analysis
will include five-year
ipsilateral breast tumour
recurrence outcomes in
this population.
An ancillary analysis
of the NRG/RTOG
ON IMPORTANCE OF DE-ESCALATION
" We all need to focus on
de-escalation strategies to
avoid over-treatment. "
ELINOR SAWYER, MD, PHD,
Professor of Clinical Oncology and
Breast Cancer Genetics,
King's College London
12
9804 and ECOG-ACRIN
E5194 trials (GS2-02)
found that tamoxifen is
a reasonable alternative
to RT after breastconservation
surgery for
what the authors called
" good risk " DCIS. The
initial results from NRG/
RTOG 9804 showed that
RT reduced ipsilateral
breast recurrence by
half at 15 years. The
impact of ET is less well
established, and most
recent studies have
left the use of ET to the
discretion of the patient
and clinician. The use
of ET is highly variable.
NRG/RTOG 9804 and
ECOG-ACRIN E5194
both enrolled patients
with " good risk " DCIS
after breast-conserving
surgery based on DCIS
size, grade, and margin.
Patients in NRG/RTOG
9804 were randomly
assigned to RT or
none, and in E5194 no
patients received RT.
When patients from
both trials with " good
risk " DCIS who did
not receive RT were
analyzed by tamoxifen
use, there was no
statistically or clinically
significant difference
in survival but risk of
an in-breast recurrence
was lower with
tamoxifen, suggesting
tamoxifen alone is a
reasonable approach
for this population.
Ongoing investigation
of molecular profiling
in RT-related decision
making may also
inform the omission
of RT in favor of ET for
more specific patient
populations.
See ECOG-ACRIN
at right 
The SUPREMO trial
(GS2-03) found that
chest wall RT following
simple mastectomy
in patients with
intermediate-risk
breast cancer does
not improve overall
survival regardless
of nodal status postmastectomy.
RT did not
improve local chest wall
recurrence, regional
recurrence, or diseasefree/metastasis-free
survival.
The authors
noted that incremental
improvements in
multidisciplinary care
likely explain the results.
A small phase I trial
(PS6-01) identified
the PARP inhibitor
rucaparib as a strong
2024 SABCS®
| Takeaways

https://events.hubilo.com/sabcs2024/session/252206 https://events.hubilo.com/sabcs2024/session/252206 https://events.hubilo.com/sabcs2024/session/252206 https://events.hubilo.com/sabcs2024/session/252206 https://events.hubilo.com/sabcs2024/session/252206 https://events.hubilo.com/sabcs2024/session/252206 https://events.hubilo.com/sabcs2024/session/252206 https://events.hubilo.com/sabcs2024/session/252206 https://events.hubilo.com/sabcs2024/session/252237

2024-SABCS-Takeaways

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