SALT LAKE CITY-Intraoperative
electron beam radiation therapy
(IOERT) may prolong the survival of
patients who have unresectable but
nonmetastatic pancreatic cancers that
are small, according to a retrospective
study reported at the 45th Annual
Meeting of the American Society for
Therapeutic Radiology and Oncology
(abstract 159). Among patients who
received this radiation therapy as part
of their comprehensive treatment,
nearly one-fifth of those with small
cancers were still alive 3 years later,
but all of those with large cancers had
"Locally advanced, nonmetastatic
pancreatic cancer is a common presentation,
and it is associated with profound
morbidity and suffering for
these patients. Our therapeutic efforts
are of a palliative nature," said lead
author Christopher G. Willett, MD,
clinical director of radiation oncology,
Massachusetts General Hospital,
and professor of radiation oncology,
Harvard Medical School.
Dr. Willett noted that various forms
of radiation therapy have been used to
treat this cancer for more than 30 years.
"To improve local control, intraoperative
electron beam radiation therapy,
typically 20 Gy, has been combined
with treatment programs of external
beam irradiation, typically on the order
of 45 to 50 Gy, and 5-FU [fluorouracil]-
based chemotherapy," he said.
The investigators studied 150 patients
with unresectable, biopsy-proven
ductal adenocarcinoma of the pancreas
treated with external beam
radiation therapy, 5-FU, and IOERT
between 1978 and 2001. Pathologists
re-reviewed the histologic findings in
patients surviving more than 3 years
to verify the diagnosis.
The patients received a wide range
of treatments with respect to both
radiation therapy and chemotherapy,
Dr. Willett noted. "As we all know,
there has been a profound treatment
evolution in this disease," he said.
"The basic theme, however, is an effort
to employ moderate- to highdose
external beam irradiation with
5-FU and IOERT at 20 Gy."
The patients had a median and
mean survival of 13 and 17 months,
respectively, Dr. Willett said. In Kaplan-
Meier analysis, their survival
rates were 54% at 1 year, 17% at 2
years, and 7% at 3 years. Eight patients
were long-term survivors, with three
patients still alive 3 to 4 years after
treatment, and five patients still alive
more than 5 years after treatment.
"In an effort to assess tumor volume,
we used a surrogate marker-
diameter of the electron cone," Dr.
Willett said. There was a significant
inverse correlation between cone diameter
and survival. About one-fifth
of the 26 patients treated with cones
that were 5 or 6 cm in diameter were
still alive at 3 years, compared with
none of the 11 patients treated with
cones that were 9 cm in diameter (17%
vs 0%), he said. Patients treated with
cones having a diameter of 7 or
8 cm had intermediate survival.
Rates of morbidity and mortality
were reasonable, Dr. Willett noted.
Overall, 0.6% of patients died during
surgery, 20% had postoperative complications,
and 15% had late complications.
Whereas delayed gastric emptying
was fairly common in the
perioperative period, abdominal abscesses
and fistulas were uncommon.
A second laparotomy was necessary in
"Those experienced with electron
beam treatment and this type of protocol
for pancreatic head carcinomas
know that the major issue is GI bleeding
due to duodenal treatment, and 16
patients experienced this," he said. A
single patient developed duodenal
obstruction, and two patients had fatal
gastrointestinal bleeding due to late
The length of hospital stay for the
treatment gradually decreased over the
study period, Dr. Willett noted. "In
our more recent time points, we were
down to about a 5- or 6-day length of
stay following a laparotomy, gastric
jejunostomy, and IOERT," he said.
Despite aggressive local treatment,
Dr. Willett said, local control of these
cancers is likely to be very problematic.
"Clearly, if one is to use IOERT for
this group of patients, selection is critical."
Dr. Willett noted that routine
laparoscopy (to rule out peritoneal
disease) and restaging by CT after fulldose
preoperative radiation therapy
and chemotherapy (to rule out progressive
and metastatic disease) have
helped identify patients who are good
candidates for intraoperative radiation
therapy. "Our current protocol is
looking at a phase I-II trial employing
external beam irradiation with oxaliplatin
[Gemzar], and restaging, with the appropriate
use of IOERT," he said.