60-65% of Stage I and Stage II invasive breast cancer cases, which constitute 15% of all cancers, are Stage I and Stage II invasive breast cancer cases. Breast-conserving surgery and radiotherapy are standard alternatives to mastectomy for most patients with Stage I and Stage II invasive breast cancer.
Due to early diagnosis, appropriate patient selection, and advancements in surgical and radiation techniques, very high rates of local control survival have been achieved with whole breast irradiation (WBI) after partial mastectomy (lumpectomy).
The ideal fractionation scheme for breast irradiation should strike a delicate balance between early and late local recurrence probabilities and the probability of side effects.
Traditional radiotherapy is administered five days a week and has been applied for approximately 5-7 weeks (i.e., approximately a total dose of 45-50 gray) for many years. This can be a tiresome process for cancer patients.
Hypofractionation refers to irradiation schemes with fewer than 5 fractions per week and doses greater than 2 Gy per fraction, and treatment can be completed in approximately 3 weeks.
Hypofractionated radiotherapy, which involves slightly increasing the dose and duration of daily sessions to shorten the total treatment time, is a treatment method that reduces the number of days spent in the hospital for patients and reduces the overall treatment duration without increasing the risk of disease or side effects.
Hypofractionation is an attractive treatment for eligible patients because it provides treatment in a shorter total duration with fewer fractions, making it more convenient for the patient. The shortened treatment duration also offers advantages such as patients and their families spending less time away from home and work, experiencing less stress, and spending less time in the hospital.
Studies have shown that outcomes in terms of local control of the disease with Hypofractionation are not lower compared to traditional radiotherapy fraction sizes in selected early-stage breast cancer patients.
Additionally, due to the lower total doses used, it results in less skin toxicity, leading to better patient care.
A meta-analysis demonstrated that HFRT (Hypofractionated Radiotherapy) and CFRT (Conventional Fractionated Radiotherapy) were equally effective following breast-conserving surgery.
No impact of patient, tumor, or treatment-related factors was observed, and a 40 Gy HFRT program in 15 fractions over 3 weeks was found to be associated with significant survival benefit.
A meta-analysis of all START trials was conducted to assess the impact of HFRT programs on various patient subgroups, independent of factors such as:
❖ Locoregional recurrence,
❖ Patient age,
❖ Tumor size,
❖ Nature of surgery,
❖ Axillary nodal status,
❖ Adjuvant systemic chemotherapy,
❖ Use of nodal irradiation,
❖ Tumor grade.
Similarly, no correlation was observed with these factors for late normal tissue morbidity in the breast.
Many centers, including the American Society for Radiation Oncology (ASTRO), the National Institute for Health and Care Excellence (NICE), and the National Comprehensive Cancer Network (NCCN), have included hypofractionation therapy in their treatment guidelines for selected patients with early-stage breast cancer.
