Hypofractionated Prone Breast IMRT plus Boost after Lumpectomy

1
Hypo-fractionated Prone Breast IMRT plus Boost
after Lumpectomy
V Croog, K Beal, and B McCormickDepartment of
Radiation Oncology, Memorial Sloan-Kettering
Cancer Center, New York, NY
Background
Results (n128 patients, 131 breasts)

• Adjuvant breast radiotherapy (RT) after
  lumpectomy is conventionally delivered with
  180-200cGy fractions to a total dose of
  4600-5040cGy /- a boost to the lumpectomy bed.
• Canadian randomized trial results published in
  2002 showed equivalent cosmesis tumor control
  at 5 years with hypo-fractionated (HF) breast RT
  without boost.1
• By 2004, we routinely began offering HF breast
  RT to appropriate patients treated in the prone
  position with an IMRT plan.
• 1. Whelan T et al JNCI 94 1143-50, 2002.

Aim

• To examine our single institution experience with
  HF IMRT to the prone breast followed by a boost
  to the lumpectomy cavity.
• Endpoints
• Patient demographics
• Acute toxicity
• Preliminary local control

Methods
Median (range) From completion of radiation
Denominator 120
breasts with available toxicity data

• Retrospective query of all patients treated with
  breast RT in our department from 01/2004 -
  12/2006
• Inclusion Criteria
• HF breast IMRT in the prone position
• 265 cGy x 16 fractions 4240 cGy
• 6 MV photons
• Boost to the lumpectomy cavity in the supine
  position
• 200 cGy x 5-7 fractions 1000-1400 cGy
• en face electrons or 6MV photons
• Study population
• 128 (36) of 358 women who underwent breast IMRT
  during the study period qualified for the
  analysis
• Represents 131 treated breasts
• Acute toxicity assessment
• The maximum point estimate of toxicity grade as
  determined by clinical assessment at weekly
  on-treatment visits during the radiation course

Conclusions

• In our single institution experience, adjuvant,
  prone HF breast IMRT followed by a boost
• Is an attractive option for a broad patient
  demographic
• Results in acute toxicity comparable to what is
  seen with
• standard fractionation
• Is completed in a timely manner without the
  need for on-
• treatment break
• Provides excellent local control based on
  preliminary
• follow-up data