Faculty Collaboration Database

A phase I/II study piloting accelerated partial breast irradiation using CT-guided intensity modulated radiation therapy in the prone position. Radiother Oncol 2013 Aug;108(2):215-9

Date

08/13/2013

Pubmed ID

23932158

DOI

10.1016/j.radonc.2013.05.039

Scopus ID

2-s2.0-84885371100 (requires institutional sign-in at Scopus site)   19 Citations

Abstract

BACKGROUND AND PURPOSE: External beam accelerated partial breast irradiation (EB-aPBI) is noninvasive with broader potential applicability than aPBI using brachytherapy. However, it has inherent challenges in daily reproducibility. Image-guide radiotherapy (IGRT) can improve daily reproducibility, allowing smaller treatment margins. Our institution proposed IG-IMRT in the prone position to evaluate dose homogeneity, conformality, normal tissue avoidance, and reliable targeting for EB-aPBI. We report preliminary results and toxicity from a phase I/II study evaluating the feasibility of EB-aPBI in the prone position using IG-IMRT.

MATERIALS AND METHODS: Twenty post-menopausal women with node-negative breast cancer, excised tumors <3.0 cm, negative sentinel lymph node biopsy, and surgical clips demarcating the lumpectomy cavity underwent prone EB-aPBI using IG-IMRT on an IRB-approved phase I/II study. All patients underwent CT planning in the prone position. The lumpectomy cavity PTV represented a 2.0 cm expansion. 38.5 Gy was delivered in 10 fractions over 5 days, such that 95% of the prescribed dose covered >99% of the PTV. Dose constraints for the whole breast, lungs and heart were met.

RESULTS: The median patient age was 61.5. Mean tumor size was 1.0 cm. 35% of patients had DCIS. Median PTV was 243 cc (108-530) and median breast reference volume was 1698 cc (647-3627). Average daily shifts for IGRT were (0.6, -4.6, 1.7 mm) with standard deviations of (6.3, 6.5, 6.4mm). Acute toxicity was G1 erythema in 80%, and G2 erythema, G2 fatigue, and G2 breast pain each occurred in 1 patient. With a median follow-up of 18.9 months (12-35), 40% of patients have G1 fibrosis and 30% have G1 hyperpigmentation. 95% of patients have good to excellent cosmesis. There have been no recurrences.

CONCLUSIONS: These data demonstrate that EB-aPBI in the prone position using IG-IMRT is well tolerated, yields good dosimetric conformality, and results in promising early toxicity profiles.

Author List

Bergom C, Prior P, Kainz K, Morrow NV, Ahunbay EE, Walker A, Allen Li X, White J

Authors

Ergun Ahunbay PhD Professor in the Radiation Oncology department at Medical College of Wisconsin
Kristofer Kainz PhD Associate Professor in the Radiation Oncology department at Medical College of Wisconsin
Natalya V. Morrow PhD Assistant Professor in the Radiation Oncology department at Medical College of Wisconsin
Phillip Prior PhD Assistant Professor in the Radiation Oncology department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Age Factors
Aged
Breast Neoplasms
Disease-Free Survival
Female
Follow-Up Studies
Humans
Mastectomy, Segmental
Middle Aged
Neoplasm Invasiveness
Neoplasm Recurrence, Local
Neoplasm Staging
Patient Positioning
Patient Safety
Pilot Projects
Postmenopause
Prognosis
Prone Position
Prospective Studies
Radiation Injuries
Radiotherapy Dosage
Radiotherapy Planning, Computer-Assisted
Radiotherapy, Intensity-Modulated
Risk Assessment
Survival Analysis
Tomography, X-Ray Computed
Treatment Outcome