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| Title: | A
Phase I/II Study Of Partial Breast Brachytherapy In Patients Who
Have Previously Received External Beam Radiation Therapy (RT) To
The Breast. |
| Author(s): | Manjeet Chadha,1 M.D., Sheldon Feldman, 2
M.D., Louis B Harrison., 1 M.D. |
| Purpose: | Mastectomy is the most widely accepted treatment
for managing local recurrence or new breast cancer in patients who
have previously received RT to the breast. With accumulating evidence
supporting partial breast irradiation, we embarked on a Phase I/II
study to evaluate the role of brachytherapy for patients presenting
with either a local breast recurrence after lumpectomy and RT or
a new breast cancer diagnosed in women who had previously received
mantle irradiation. |
| Materials & Methods: | In consideration of the history of prior RT and
the lack of established safety of re-treatment, the protocol permitted
only interstitial low dose-rate brachytherapy. For patients with
locally recurrent breast cancer, the protocol design included a
dose escalation regimen: the first 6 patients received 30Gy. After
a minimum follow up period of 12 months, which confirmed no unacceptable
acute toxicity in the treated breast, the total brachytherapy dose
was increased to 45Gy. All patients with prior mantle irradiation
received 45Gy. Eligibility included all histologic subtypes presenting
as a unifocal lesion. All patients underwent a lumpectomy with negative
microscopically-assessed surgical margins prior to brachytherapy.
Systemic therapy, when recommended started after a minimum 2- week
interval following removal of brachytherapy catheters. From 1999
to present, 17 patients have completed treatment. Fourteen patients
had prior RT for breast cancer, 2 for Hodgkin’s disease and
1 for Non Hodgkin’s lymphoma. At the time of brachytherapy,
13 patients had an infiltrating cancer and 4 patients had DCIS.
The median tumor size was 0.8cm (0.4cm to 1.5cm). The median number
of interstitial catheters used was 11. Brachytherapy was delivered
at a dose rate 40-50 cGy/hour. All patients received prophylactic
antibiotics. Three patients have received systemic chemotherapy
and 2 patients are on hormones. All patients have been followed
by the multidisciplinary team. |
| Results: | The median time from the initial RT to the current
brachytherapy is 91.8 mo (range 28.5mo to 321.3mo). The median follow
up after brachytherapy is 30.6 mo (range: 9mo to 81mo). No patients
developed an infection. No skin toxicity > RTOG grade 2 was observed.
No excessive fibrosis or necrosis has been observed. Most patients
with prior history of breast cancer were noted to have asymmetry
in breast size as a result of the second lumpectomy performed prior
to brachytherapy. This factor influenced the number of catheters
placed at the lumpectomy site. With breast asymmetry as a given,
the cosmetic result observed in all patients has been good to excellent.
One patient developed a local breast recurrence at 27 months following
brachytherapy she underwent a salvage mastectomy and remains free
of disease. The 3-year Kaplan Meier analysis of breast conservation
rate and local disease-free survival following brachytherapy is
89%. The overall survival is 93%. |
| Conclusion: | The preliminary experience using brachytherapy
ina previously irradiated breast suggests low complication rates,
and acceptable cosmetic results. The relatively high local control
rates and freedom from mastectomy for local recurrence warrants
further investigation to establish brachytherapy as an acceptable
alternative to mastectomy for selected patients. |
Copyright © 2006