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HER2 therapy for early-stage breast cancer has altered presentation
of HER2-positivemetastatic breast cancer
T
he introduction of HER2 therapy for
early-stage breast cancer has altered
the presentation of HER2-positive
metastatic breast cancer significantly over
the past decade. Patients who present with
de novo metastatic breast cancer and harbour
fewer than two sites of metastatic disease
are more likely to achieve prolonged overall
survival when treated with HER2 therapy
combined with chemotherapy.
This observation was based on results of a
retrospective, single-centre review.
Giuseppe Gullo, MD, of St. Vincents
University Hospital, Dublin, Ireland,
explained that the introduction of anti-
HER2 therapy has significantly improved the
objective response rate and overall survival
of patients with HER2-positive metastatic
breast cancer.
Though HER2-positive metastatic breast
cancer remains incurable, a meaningful
minority of patients on first-line HER2
therapy experience a prolonged phase of
disease control.
Clinical factors at presentation of metastatic
breast cancer associated with overall
survival, however, have not been fully
elucidated and are not part of baseline
patient assessment.
Dr Gullo and colleagues analysed 134
consecutive patients with HER2-positive
metastatic breast cancer treated between
2000 and 2016. Patient characteristics at
initiation of HER2 therapy were:
•
Median age: 55 (range 25–83) years
•
Oestrogen or progesterone receptor
positivity: n=76 (57%)
•
Oestrogen and progesterone receptor
negativity: n=47 (35%)
•
Unknown oestrogen/progesterone
receptor status: n=11 (8%)
•
Fewer than two metastatic sites: n=98
(73%)
•
More than two metastatic sites: n=36
(27%)
•
Visceral disease: n=85 (63%)
•
HER2 therapy + chemotherapy: n=116
(86%).
Median follow-up duration was 23
months (range 0.3–193). The proportion
of patients treated for relapsed HER2-
positive metastatic breast cancer decreased
significantly from 2000–2005 (83%) to
2011–2016 (relapsed metastatic breast
cancer, 42%), whereas de novo HER2-
positive metastatic breast cancer increased
significantly (17% to 58%) over the same
time interval. This increase was most likely
an effect of the introduction of HER2 therapy
for early-stage breast cancer. Such routine
treatment began in 2005.
Patients with de novo metastatic breast
cancer experienced longer median overall
survival (44 months [95% CI 29–84]) than
those with relapsed metastatic breast cancer
(38 months [95% CI 23–47]).
Longer overall survival was significantly
associated with fewer than two sites of
metastatic disease (P = 0.015), the absence
of visceral metastases (P = 0.048), and
treatment with HER2 therapy in association
with chemotherapy (P = 0.022).
On multivariate analysis, de novo metastatic
breast cancer (P = 0.048) and fewer than two
metastatic sites at diagnosis (P = 0.001) were
associated with significantly longer overall
survival and reduced risk of death.
Twenty-one patients (16%) achieved
complete response, 16 who have not relapsed.
All 16 patients with durable complete
response received anti-HER2 therapy with
chemotherapy, had fewer than two sites
of metastatic disease, and had not been
pretreated with HER2 therapy previously.
Dr Gullo said that the introduction of HER2
therapy for early-stage breast cancer over a
decade ago has altered the presentation of
HER2-positive metastatic breast cancer
significantly, with a larger proportion of
patients now presenting with the de novo
metastatic disease.
Patients who present with de novo metastatic
breast cancer and harbour fewer than two
sites of metastatic disease are more likely to
achieve prolonged overall survival and even
sustained disease remission when treated
with HER2 therapy in combination with
chemotherapy.
These clinical factors may be used to
prognosticate patient outcome and can be
incorporated into clinical trials of HER2
therapy.
PracticeUpdate Editorial Team
CONFERENCE COVERAGE
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PRACTICEUPDATE HAEMATOLOGY & ONCOLOGY