SAN DIEGO, Sept. 24, 2017 /PRNewswire-USNewswire/
-- Combining radiation therapy with chemotherapy for patients
with limited metastatic non-small cell lung cancer (NSCLC) may curb
disease progression dramatically when compared to NSCLC patients
who only receive chemotherapy, according to a new randomized phase
II clinical trial reported today at the 59th Annual Meeting of the
American Society for Radiation Oncology (ASTRO). Progression-free
survival in the trial escalated from 3.5 months to 9.7 months with
the addition of radiation therapy delivered to all the metastatic
sites of lung cancer as well as the primary disease site.
Treatment-related side effects were similar for the two treatment
approaches.
Lung cancer claims the most cancer-specific deaths of any tumor
type. Few existing treatments offer durable survival benefits for
patients whose NSCLC has spread past the lungs, due in part to the
aggressive nature of lung cancer and its propensity to progress,
even following treatment. Research on metastatic colorectal cancer
and sarcoma, however, suggests a potential benefit from adding
local therapy—treatment directed specifically at the tumor cells—to
the standard approach of systemic therapy. In these studies, adding
radiation or/and surgery bolstered the ability of systemic
therapies, such as chemotherapy, to control disease and improve
survival in patients with few metastases.
"Even in the era of immunotherapy, there are not large numbers
of metastatic NSCLC patients with durable responses to systemic
therapy. In our trial, however, the addition of radiation therapy
directed at each of the cancerous areas greatly improved how
patients responded to subsequent rounds of chemotherapy," said
Puneeth Iyengar, MD, PhD, lead author of the study and an assistant
professor of radiation oncology at the University of Texas Southwestern Medical Center in
Dallas. "This finding suggests that local treatments,
including radiation, could work in concert with chemotherapy to
prolong the amount of time before recurrence occurs in patients
with limited sites of metastatic NSCLC."
The study was a randomized phase II trial testing whether the
addition of local treatment, in the form of consolidative radiation
therapy, to the standard treatment of systemic therapy improved
progression-free survival for patients with limited metastatic
NSCLC. Eligible patients included those with stage IV disease,
spread to six or fewer sites including the primary tumor site, and
who responded at least partially to first-line/induction
chemotherapy.
Patients were randomly assigned to receive either maintenance
chemotherapy alone (15 patients) or a combination of stereotactic
ablative radiotherapy (SAbR)—also known as stereotactic body
radiation therapy or SBRT—to all sites of disease followed by
maintenance chemotherapy (14 patients). Radiation to metastases was
offered as a single fraction (to 21-27 Gray
(Gy)), three fractions (to 26.5-33 Gy) or five fractions (to
30-37.5 Gy) of SAbR (regimens were biologically equivalent).
Radiation to the primary disease site was delivered via SAbR
where possible, or through 15 fractions of hypofractionated
radiation therapy if the primary tumor was too central or involved
mediastinal nodes. Maintenance chemotherapy was left to the
discretion of the treating medical oncologists and consisted of
pemetrexed, docetaxel, erlotinib or gemcitabine.
Twenty-nine patients were accrued between April 2014 and July
2016. The median patient age was 70 years (range 51-79
years) for the patients receiving maintenance chemotherapy only and
63.5 years (range 51-78) for the patients receiving SAbR to
metastases followed by maintenance chemotherapy. Most patients were
male (69%). Eighty-six percent of all patients had tumors with
non-squamous histologies. Thirty-one lesions were treated with
radiation in the 14 patients that received local therapy.
The median follow-up for this report was 9.6 months (range
2.4-30.2 months). Patient accrual was stopped ahead of schedule
after an unplanned interim analysis found substantially improved
survival rates in the arm receiving local therapy, matching similar
findings in a parallel trial.
The interim analysis found a median progression-free survival
rate of 9.7 months with consolidative radiation therapy followed by
chemotherapy, versus 3.5 months for maintenance chemotherapy alone
(p = 0.01; Hazard Ratio (HR) = 0.304, 95% CI 0.113-0.815). Survival
rates were estimated using the Kaplan-Meier method and compared
using the log-rank test and Cox proportional hazard models.
Specifically, rates of local control and delay in distant
metastases also favored the approach incorporating radiation with
systemic therapy. In the arm with consolidative local therapy,
there were no recurrences in original sites of gross disease versus
seven failures in original sites of gross disease in the arm
receiving only maintenance therapy. At the time of analysis, 10 of
the 15 patients receiving maintenance chemotherapy-only had
progressed, compared with four of the 14 patients also receiving
radiation. None of the recurrences among the latter patients were
in areas treated directly with radiation therapy.
Treatment-related side effects were similar between the two
treatment arms, indicating that the addition of local therapy was
well-tolerated by patients. There were no grade 5 toxicities
attributable to study treatment. On the maintenance
chemotherapy-only arm, there were two grade 3 and one grade 4
toxicities. On the SAbR plus maintenance chemotherapy arm, there
was one grade 4 toxicity.
"These findings verify that progression-free survival for
limited metastatic disease really is no different than it is for
widely metastatic disease, suggesting that local therapy could play
an important future role in survival outcomes," said Dr. Iyengar.
"Moreover, the addition of consolidative radiation did not increase
toxicity, which allowed patients to continue on to additional
systemic therapy that is important to controlling aggressive
metastatic disease."
Next steps for this research include a larger, randomized phase
III trial to test progression-free survival, as well as overall
survival. While results indicate a clear benefit of adding local
therapy for the management of limited metastatic NSCLC, Dr. Iyengar
stressed the need for confirmation in a larger prospective
trial.
"There is a significant possibility that local therapy, such as
consolidative radiation, may become an important part of the
management of limited metastatic NSCLC patients, but this
validation must take place in randomized phase III studies.
Interested patients should seek more information about the ongoing
NRG LU 002 and SARON trials."
The abstract, "Consolidative radiotherapy for limited metastatic
non-small cell lung cancer (NSCLC): A randomized phase II trial,"
will be presented in detail during a news briefing and the Plenary
Session at ASTRO's 59th Annual Meeting in San Diego (full details below). The study is
also available beginning today in JAMA Oncology. To schedule an
interview with Dr. Iyengar and/or outside experts in 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: Plenary, Monday,
September 25, 2:15 – 3:45 p.m.
Pacific time, San Diego
Convention Center, Ballroom 20
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)
- ASTRO's clinical practice statements and guidelines
- Additional brochures, videos and information on radiation
therapy from ASTRO's patient site, RTAnswers.org
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