SAN DIEGO,
Sept. 24, 2017
/PRNewswire-USNewswire/ -- A new study involving patients
with stage IV cancer finds that treatment with radiation therapy
and immunotherapy can halt the growth of tumors by stimulating the
body's immune system to attack the cancer. In the phase II trial,
patients with end-stage cancer that had spread to the lungs or
liver demonstrated a favorable response to the combined treatment.
Between 30 and 60 percent of the patients, depending on the
treatment arm, found that their cancer stopped spreading. Findings
will be presented today at the 59th Annual
Meeting of the American Society for Radiation Oncology
(ASTRO).
"This combination of immunotherapy and radiation therapy
was safe and well-tolerated by patients with late-stage cancers. We
were surprised that a large percentage of patients achieved stable
disease several months after treatment—meaning that while their
tumors didn't shrink, they did stop growing," said James Welsh, MD, lead author of the study and an
associate professor of radiation oncology at The University of Texas MD Anderson Cancer Center in
Houston.
"It appears that the radiation helped turn the tumor into
a vaccine to stimulate an immune response. This heightened immune
response was able to keep the tumors stable. Longer follow-up is
needed to determine if this benefit of stable disease will endure
over time."
One hundred patients were enrolled in a phase II trial
examining a combination of high-dose radiation therapy plus
immunotherapy for patients with various types of stage IV cancers.
Eligible patients included those with metastatic disease that was
resistant to standard therapies, with one or more lesions in the
liver or lung that was/were amenable to stereotactic radiation and
one or more additional metastases not touching the lung or liver
lesion. The majority of patients (55%) had adenocarcinomas, while
13 percent had squamous cell carcinomas and the remaining 32
percent had various other histologies.
All patients received four cycles of ipilimumab (3 mg/kg
every three weeks) and stereotactic body radiation therapy (SBRT)
to the site(s) of metastasis in either the liver or the lungs.
Radiation therapy was given either concurrently with or
sequentially to immunotherapy. Concurrent radiation began on day
two of the first immunotherapy cycle, to a total dose of 50 Gray
(Gy) delivered in four fractions. Sequential radiation was given
one week after the second immunotherapy cycle to a total radiation
dose of 50 Gy delivered in four fractions, or 60 Gy in 10 fractions
for larger lung or liver metastases—typically, those larger than
four centimeters. Patients were enrolled in a nonrandomized fashion
into one of the five treatment cohorts: concurrent lung, sequential
50-Gy lung, concurrent liver, sequential 50-Gy liver, and
sequential 60-Gy liver or lung. There were 20 patients in each
treatment arm.
Stable disease was achieved for half of the patients in
the sequential 50-Gy lung cohort, 45 percent of the concurrent-lung
group, 35 percent of the concurrent liver group and 30 percent of
the sequential 50-Gy liver group. Sixty percent of patients in the
larger-lesion, higher-dose radiation group demonstrated a favorable
response to treatment.
The median progression-free survival (PFS) for all
patients following radiation therapy combined with immunotherapy
was five months (95% CI = 2.7-7.2 months). Median overall survival
(OS) was 12 months (95% CI = 9.3-14.6 months). Patients who
received sequential radiation to lung metastases rather than to
liver metastases had better PFS (p = 0.055, 95% CI = 3.7-6.4) and
OS (p = 0.059, CI = 7.9-20.0). No differences were found between
the concurrent lung or liver groups for progression-free (p = 0.2)
or overall (p = 0.3) survival.
There were no complete responses to treatment, but a
partial response was found for three patients who received SBRT
concurrently with ipilimumab, including two patients (10%) on the
concurrent lung arm and one patient (5%) on the concurrent liver
arm. No patients in the sequential radiation groups experienced a
partial response.
"A small percentage of patients experienced a potential
abscopal effect, where tumors that were not irradiated became
smaller after we treated different sites with radiation," explained
Dr. Welsh. "For example, one patient with anaplastic thyroid
cancer—one of the deadliest types of cancer—experienced a reduction
in the primary tumor after we irradiated a lung metastasis. This
patient had controlled disease for more than 13 months."
Lesions from non-small cell lung cancer (NSCLC) were most
responsive to the combined treatment; two thirds of these patients
had a favorable response (partial response or stable disease)
following SBRT plus immunotherapy. Response to treatment was scored
using immune-related criteria (irRC). Partial response represented
a 50 percent or greater decrease in tumor size. Progressive disease
represented a 25 percent increase in tumor size. Stable disease
responses included those that did not fall into complete, partial
or progressive response categories.
No patients experienced Grade 4 or 5 treatment-related
side effects. Twenty-seven patients experienced Grade 3 toxicities
related to immunotherapy, including colitis (8 patients), diarrhea
(7 patients), rash (4 patients), elevation of liver enzymes (3
patients), hypophysitis (3 patients), elevation of bilirubin (1
patient) and intestinal obstruction (1 patient). Two patients
experienced Grade 3 toxicities related to combination therapy,
including one patient with an increase in liver enzymes and one
patient with pneumonitis. Side effects were evaluated using the
Common Terminology Criteria for Adverse Events, version
4.0.
"We found that the addition of SBRT for patients who are
on immunotherapy to be safe and well-tolerated, meaning that
radiation oncologists can feel confident continuing immunotherapy
for most patients when adding SBRT to lung or liver metastases. In
fact, there may be additional benefit from combining the therapies
in terms of improved disease control. Follow-up research in larger
clinical trials is needed to determine which types of tumors and
patients will respond best to this immunotherapy-radiation
approach," said Dr. Welsh.
The abstract, "Phase II 5-arm trial of
ipilimumab plus lung or liver stereotactic radiation for patients
with advanced malignancies," will be presented in
detail during a news briefing and the clinical trials session at
ASTRO's 59th Annual Meeting in San
Diego (full details below). To schedule an interview with
Dr. Welsh and/or outside experts in immunotherapy and lung
cancer, contact ASTRO's media relations team on-site
at the San Diego Convention Center
September 24 through 27, by phone at
703-286-1600 or by email at
press@astro.org.
ATTRIBUTION TO THE AMERICAN SOCIETY OF RADIATION
ONCOLOGY (ASTRO) ANNUAL MEETING REQUESTED IN ALL
COVERAGE.
This news release contains additional and/or updated
information from the study author(s). Full
original abstract and author disclosures available from
press@astro.org or at
www.astro.org/annualmeeting.
Study Presentation Details
- News Briefing: Sunday, September
24, 1:00 – 2:00 p.m. Pacific
time, San Diego Convention
Center, room 24C, webcast:
http://www.bit.do/astro17-1
- Scientific Session: Clinical Trials, Sunday, September 24, 3:15 – 4:45 p.m. Pacific time, San Diego Convention Center, Ballroom
20
Additional Information on Radiation Therapy and
Immunotherapy
- Immunology Primer, by Heather McGee, MD, PhD
- Radiation Oncology and Immunotherapy Primer,
by Michelle Kim, MD
Resources on Lung Cancer and Radiation
Therapy
- Digital brochure: Radiation Therapy for Lung
Cancer (Spanish
version)
- Videos: Radiation Therapy for Lung
Cancer (Spanish
version), An Introduction to Radiation
Therapy (Spanish
version)
- Additional brochures, videos and
information on radiation therapy from ASTRO's patient
site, RTAnswers.org
- ASTRO's clinical practice statements and
guidelines
ABOUT ASTRO'S ANNUAL
MEETING
ASTRO's 59th Annual Meeting, the
world's largest scientific meeting in radiation oncology, will be
held September 24-27, 2017, at the
San Diego Convention Center. The
2017 Annual Meeting is expected to attract more than 11,000
attendees from across the globe, including oncologists from all
disciplines and members of the entire radiation oncology team. More
than 2,800 abstracts sharing results from clinical trials and other
research studies will be presented in conjunction with educational
sessions and keynote addresses that underscore the meeting's theme,
"The Healing Art and Science of Radiation Oncology." Led by ASTRO
President Brian Kavanagh, MD, MPH,
FASTRO, the 2017 meeting will feature keynote addresses from
Richard D. Zane, MD, FAAEM, Chief
Innovation Officer for the University of
Colorado Health System; Lucy Kalanithi, MD, FACP, widow of
Paul Kalanithi, MD, the best-selling author of "When Breath Becomes
Air," with Heather Wakelee, MD,
Paul's oncologist; and Vinay K.
Prasad, MD, MPH, an assistant professor of medicine at the
Oregon Health & Science University. During the four-day
meeting, more than 200 exhibitors will demonstrate cutting-edge
technology and medical device innovations for radiation oncology.
Visit us online for more information about
ASTRO's 59th Annual Meeting
or press opportunities at the
meeting.
ABOUT ASTRO
The American Society
for Radiation Oncology (ASTRO) is the world's largest radiation
oncology society, with more than 10,000 members who are physicians,
nurses, biologists, physicists, radiation therapists, dosimetrists
and other health care professionals who specialize in treating
patients with radiation therapies. The Society is dedicated to
improving patient care through professional education and training,
support for clinical practice and health policy
standards, advancement of science and research, and
advocacy. ASTRO publishes three medical journals,
International Journal of Radiation Oncology • Biology • Physics
(www.redjournal.org),
Practical Radiation Oncology
(www.practicalradonc.org)
and Advances in Radiation Oncology
(www.advancesradonc.org);
developed and maintains an extensive patient website, RT
Answers
(www.rtanswers.org); and
created the Radiation Oncology Institute
(www.roinstitute.org), a
nonprofit foundation to support research and education efforts
around the world that enhance and confirm the critical role of
radiation therapy in improving cancer treatment. To learn more
about ASTRO, visit www.astro.org
and follow us on our
blog,
Facebook and
Twitter.
Contact: Liz
Gardner
703-286-1600
liz.gardner@astro.org
Leah Kerkman
Fogarty
703-839-7336
leah.fogarty@astro.org
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SOURCE American Society for Radiation Oncology