By Dr. Mahwish Akhter
Abstract:
INTRODUCTION
The FAST-Forward trial has reshaped adjuvant radiotherapy for early-stage breast cancer by demonstrating the
non-inferiority of an ultra-hypofractionated regimen—26 Gy in
5 fractions over 1 week—compared to the widely used 3-week
regimen of 40 Gy in 15 fractions. This approach offers
significant logistical advantages, including reduced treatment
time, improved patient convenience, and potential cost savings.
However, its rapid adoption requires careful evaluation of
dosimetric safety, especially in varied clinical settings. Our
study presents initial institutional experience with this regimen,
emphasizing the importance of meticulous planning to ensure
compliance with organ-at-risk (OAR) constraints and safe
integration into routine practice.
METHOD
We retrospectively analyzed 16 patients with early-stage breast
cancer treated post-lumpectomy or post-mastectomy using
either 3D conformal radiotherapy (3D-CRT) or
intensity-modulated radiotherapy (IMRT). Nodal irradiation
was excluded. Treatment plans were assessed for planning
target volume (PTV) coverage and doses to critical structures.
Key dosimetric parameters included:
– PTV V95% ≥ 95%
– Heart (left-sided): V7 < 5%, 1.5 Gy < 30%
– Ipsilateral lung: V8 < 15%
– Contralateral breast: Maximum dose < 3 Gy
Dose-volume histograms (DVHs) were analyzed to verify
compliance with FAST-Forward criteria.
RESULTS
All treatment plans achieved adequate PTV coverage, with
V95% > 95%. Mean heart dose (V7) was 3.02%, and ipsilateral
lung dose (V8) averaged 13.08%, both within acceptable
limits. The maximum dose to the contralateral breast remained
below 3 Gy in all cases. However, the secondary heart
constraint—1.5 Gy < 30%—was not consistently met in IMRT
plans, indicating a potential area for optimization.
LIMITATIONS
This study did not incorporate Deep Inspiration Breath Hold
(DIBH), which may have improved heart sparing, particularly
in left-sided cases. Additionally, the small sample size and
retrospective nature limit generalizability, though findings
align with published data.
CONCLUSION
Ultra-hypofractionated radiotherapy using 26 Gy in 5 fractions
demonstrates acceptable dosimetric profiles in early-stage breast cancer patients treated post-lumpectomy or
post-mastectomy. With careful planning and adherence to
protocol-defined constraints, this regimen can be safely
implemented, supporting its continued use in clinical practice.