Gastrointestinal Cancers Symposium
SAN FRANCISCO — Chemotherapy with dose-painted intensity-modulated
radiation therapy for anal cancer produced similar OS and DFS as 2 years of
treatment with chemotherapy and conventionally delivered radiation therapy, but
with fewer significant adverse events, results from the phase 2 Radiation
Therapy Oncology Group study 0529 showed.
Lisa Kachnic, MD, chair of radiation oncology at
Boston University and one of the study’s researchers, said the Radiation
Therapy Oncology Group (RTOG) will now use dose-painted IMRT as the standard
radiation technique in future trials assessing novel agents combined with
radiation to treat anal cancer.
“Dose-painted IMRT with 5-fluorouracil and
mitomycin-C chemotherapy for anal canal cancer is associated with significant
sparing of grade-3+ dermatologic and gastrointestinal toxicity without
compromising 2-year outcomes,” Kachnic said.
She presented the results during a press conference in
advance of the 2011 Gastrointestinal Cancers Symposium.
Kachnic and colleagues analyzed OS and DFS for 52
patients with stage II/stage III disease treated with IMRT and 5-FU/mitomycin-C
chemotherapy. The primary endpoint for the study was a 15% reduction in acute
grade 2 or higher gastrointestinal/genitourinary toxicities compared with
results from the 325-patient, 5-FU/mitomycin-C arm of RTOG 9811. That trial
used conventionally delivered radiation.
At a median follow-up of 26.7 months, 2-year DFS was 77%
and OS was 86%. Kachnic said those outcomes were similar to results from RTOG
9811. At 2 years, DFS in that trial was 75% and OS was 91%. Other outcomes
proved to be similar (see graph).
Patients underwent a median of 43 days of dose-painted
IMRT compared with 49 days for conventional radiation therapy in RTOG 9811.
Kachnic said fewer days of radiation are important because earlier studies have
shown that a longer duration of radiation increases the risk for local
Clinical response was 64% at 8 weeks and 81% at 12 weeks
after dose-painted IMRT.
Patients in RTOG 0529 experienced fewer incidents of
grade-3/grade-4 dermatologic and gastrointestinal acute toxicity compared with
patients in RTOG 9811. The study did not the meet primary endpoint, but Kachnic
said dose-painted IMPRT was associated with a significant sparing of grade-3+
She said dose-painted IMRT was also associated with an
unexpected reduction of more than 50% for grade-3+ dermatologic toxicities.
– by Jason Harris
For more information:
- Kachnic L. #368. Presented at: the 2011
Gastrointestinal Cancers Symposium; Jan. 20-22, 2011; San Francisco.
Disclosure: Dr. Kachnic has no relevant financial
The majority of patients with anal cancer, almost 85%, are cured with
chemotherapy and radiation alone. Because of this high success rate,
researchers are now focused on ways to improve the side effect profile of this
already very effective therapy. After short-term follow-up, IMRT appears to be
as effective as conventional radiation in the treatment of anal cancer, but
with decreased side effects. While larger studies will need to be performed and
longer follow-up is required, IMRT may emerge as a key treatment modality for
- Jennifer C. Obel, MD,
Professor of Medicine, University of Chicago