ablation (RFA) plus radiation is an
effective and well-tolerated minimally
invasive technique that warrants
further investigation in early-stage
non-small-cell lung cancer (NSCLC),
Thomas A. Dipetrillo, MD, said at
the 10th Annual International Conference
on Screening for Lung Cancer.
In 25 NSCLC patients with T1
and T2 disease treated with the RFA/
radiation combination, 1-year survival
was 81%, reported Dr. Dipetrillo,
assistant professor of radiation oncology,
Brown University Medical
School. "Our data suggest that these
two therapies are very complementary,"
RFA is a newer technology that
researchers believe will be useful in
early NSCLC cases that cannot be surgically
excised because of coexisting
morbidities, Dr. Dipetrillo said.
The RFA technique involves insertion
of a probe into the tumor. A
high-frequency electrical current is
generated and applied through the
probe. Agitation of ions in tissue results
in frictional heat, causing coagulative
necrosis of tissue.
"The heat can be directed at a relatively
well-defined area, depending on
the type of probe that is used," Dr.
Dipetrillo said. "You can get to about
a 3-cm spheroid type shape, and the
probe can be put in through CT fluoroscopy,
with excellent positioning."
According to Dr. Dipetrillo, RFA
is a single-day procedure that is "about
as safe as biopsy itself. . . . We haven't
seen any increase in toxicity above
biopsy, at least for RFA alone." The
procedure takes about 1 to 3 hours in
the imaging room and patient recovery
takes about 3 hours.
In their initial experience with RFA
alone, Dr. Dipetrillo and his colleagues
noted that starting at about a year
after the procedure, there were some
increases in density along the peripheral
region of the initial area of ablation.
Going on the theory that not
enough current was being generated
to allow appropriate heating, they
went on to combine RFA with radiation.
Phase I Study
At Rhode Island Hospital, the investigators
undertook a phase I trial
including 25 consecutive patients (age
range, 58 to 85) with T1 or T2 NSCLC
(biopsy proven and PET-confirmed
node negative). All patients were medically
inoperable, typically due to
cardiopulmonary disease, and had
received up-front cytoreduction with
RFA, followed by 3D conformal
radiation ± chemotherapy. Follow-up
included PET (6 and 12 months) and
CT (every 3 months for the first year, then every 6 months). Pulmonary
function tests were given 6 months
after completion of therapy.
The mean lesion size treated was
3.4 cm. Immediately after the procedure,
the pneumothorax rate was
about 12%, consistent with what is
expected from biopsy. There were no
treatment-related deaths or grade 3-4
toxicities, "although these were veryhigh-
risk patients," he said. Investigators
noted no significant changes
in pulmonary function tests.
With a median follow-up of 17.2
months (range, 4 to 48 months), 1-
year survival is 81% (16 of 25 patients).
There have been five cancer
deaths (four in T2 patients); the remaining
four deaths were related to
COPD or cardiovascular disease and
occurred at least 6 months after RFA/
radiation treatment. Of five patients
who developed metastatic disease,
four were T2 patients. There was one
local and one intrathoracic recurrence,
both in T2 patients.
Now, the investigators have moved
from external radiation to brachytherapy.
In an open protocol with an
enrollment goal of 25 patients with
lesions 3 cm or less in size, they are
using brachytherapy immediately following
RFA. "We have inserted a
brachytherapy catheter to try to isolate
an area of treatment and give 18
to 20 Gy to approximately 5 mm
around that area," he said. To date,
12 of 14 patients have been treated
successfully. "With median follow-up
of 8 months, there were no local or
systemic recurrences and very little
toxicity, although these are very early
data," Dr. Dipetrillo said.