Transcript Hypofractionated Radiation Therapy for Early Stage Breast Cancer Patrick J. Gagnon, M.D. Resident, PGY-4 Radiation Medicine, OHSU Providence Hospital Breast Conference November 5, 2008

Hypofractionated Radiation Therapy for
Early Stage Breast Cancer
Patrick J. Gagnon, M.D.
Resident, PGY-4
Radiation Medicine, OHSU
Providence Hospital
Breast Conference
November 5, 2008
Outline
Hypofractionation
Benefits
Radiobiology
Disadvantages
Breast Conservation
Current Standard-of-Care
Hypofractionated Radiation
Whelan Data – JNCI (2002)
Whelan Update – ASTRO (2008)
Hypofractionation - Defined
Larger doses of radiation per treatment
fraction delivering a full course of treatment
over a shorter period of time compared to
conventional fractionation
Typical fraction sizes: 1.8 – 2.0 Gy per day
Hypofractionation: 2.25 - >20 Gy per day
SBRT (lung, liver), pre-op rectal, glottic larynx
Hypofractionation - Benefits
Reduced cost (fewer fractions, increased
throughput)
Increased convenience (1-3 weeks vs 6-7)
Decreased patient travel and lodging
Increased treatment compliance and acceptance
of therapy
Improved access to care
Radiobiology
Hypofractionation - Radiobiology
 Increased dose per
fraction, increased
tumor kill
 Relative dose to lateresponding tissues is
higher than to earlyresponding tissues
(mucosa, tumor) raising
concerns about latetissue toxicity
Hypofractionation - Disadvantages
Late normal tissue toxicity
Cosmesis
Loco-regional control
Biologically equivalent dose may actually be less
than compared to standard fractionation
Breast Applications
Standard BCT includes lumpectomy with
negative margins followed by whole breast
radiation therapy
Radiation doses typically 45-50 Gy +/lumpectomy cavity boost to ~61 Gy
Fraction sizes 1.8 – 2.0 Gy, often 33 fractions
delivered over 6.5 weeks
Excellent local control and cosmesis
Long-term Results of a Randomized Trial of Accelerated
Hypofractionated Whole Breast Irradiation Following Breast
Conserving Surgery in Women with Node-Negative Breast Cancer
Whelan et. al., Canada
Plenary session, 50th annual ASTRO Meeting,
Boston
Initial data published in JNCI in 2002
10 year follow-up data presented at ASTRO
Randomized Trial of Breast Irradiation Schedules
After Lumpectomy for Women With Lymph NodeNegative Breast Cancer
Results initially reported with median followup of 69 months (JNCI 2002;94:1143-50)
1234 patients, T1-2 N0 disease, lumpectomy with
negative margins, 2 arm randomization
622 received 42.5 Gy in 16 fractions and 612
received 50 Gy in 25 fractions
Primary endpoint local recurrence
Secondary endpoints were distant recurrence,
cosmesis, and late radiation toxicity
Randomized Trial of Breast Irradiation Schedules
After Lumpectomy for Women With Lymph NodeNegative Breast Cancer
Randomized Trial of Breast Irradiation Schedules
After Lumpectomy for Women With Lymph NodeNegative Breast Cancer
Local in-breast recurrence data from original study with 5 year follow-up
Long-term Results of a Randomized Trial of Accelerated
Hypofractionated Whole Breast Irradiation Following Breast
Conserving Surgery in Women with Node-Negative Breast Cancer
 Median follow-up now 144 months
 Local Recurrence at 10 years
6.2% (hypofrac)
6.7% (standard frac)
 Cosmesis at 10 years (EORTC Rating System)
70% excellent (hypofrac)
71% excellent (standard frac)
 Late mod-severe skin/sub-Q toxicity at 10 years
6% skin & 8% sub-Q (hypofrac)
3% skin & 4% sub-Q (standard frac)
Long-term Results of a Randomized Trial of Accelerated
Hypofractionated Whole Breast Irradiation Following Breast
Conserving Surgery in Women with Node-Negative Breast Cancer
 Conclusions
 Accelerated hypofractionated whole breast irradiation
provides excellent long-term local control and limited late
morbidity
 Benefits of convenience and cost
 Questions over late normal tissue toxicity remain
 Standard arm does not match typical U.S. whole breast
regimen (higher whole breast dose, no boost)
 Cosmesis based on physician assessment rather than
patient assessment
 Is this the new “standard-of-care” or do we rely on our
mature data and extensive clinical experience with
conventionally fractionated whole breast radiation?
Acknowledgements
Thank you to Dr. Cha and the entire
Providence Radiation Oncology Department
Providence Breast Conference
Dr. Charles Thomas, OHSU Radiation Medicine
Dr. Carol Marquez, OHSU Radiation Medicine
Dr. John Holland, OHSU Radiation Medicine