Prospective Comparative Study of Hypofractionated Adjuvant Radiotherapy in 2 Virsus 3 Weeks in Breast Cancer

Female breast cancer (BC) has been the leading cause of cancer morbidity and mortality among women in the

majority of countries for decades. In 2020, there were an estimated 2.3 million new cases and 685,000 deaths

from female BC worldwide, which accounted for one in four cancer cases and one in six cancer deaths among

women.

u For women with newly diagnosed, non-metastatic breast cancer, treatment consists of a multidisciplinary

approach that involves input from surgery, radiation oncology, and medical oncology. The objective of adjuvant

radiation therapy (RT) is to eradicate any tumor deposits remaining following surgery for patients treated by

either breast-conserving surgery or mastectomy . Doing so reduces risk of locoregional recurrence and improves

breast cancer-specific and overall survivals.

u A historical regimen of 25-28 fractions over 6 weeks was adopted for radiotherapy (RT) following breast-

conserving surgery (BCS) and total mastectomy. An early assumption that breast cancer cell lines might be more

sensitive to fractional doses than acute skin reactions and other squamous carcinomas lead to development of the

hypofractionated RT (HypoRT) approach, which elevated fractional dose up to 3 Gy with reduced total

dose/fractions, for obtaining radiobiological equivalence to a traditional regimen of 50-50.4 Gy in 25-28

fractions.

u Recently, the American Society of Radiation Oncology released a task force guideline recommending

hypofractionated radiotherapy for all women of any age whether they had received chemotherapy or not ,Their

evidence-based recommendations were supported by studies from Canada and the United Kingdom.

u Benefits of HypoRT include both, radiobiologic advantages and reduced length of treatment courses, for

improving healthcare resources and patient convenience. Consequently, HypoRT has been widely adopted

worldwide based on a series of randomized clinical trials .

u Recently, HypoRT over 3 weeks and with shorter courses of 5 fractions have been recommended in treatment

guidelines.

u Regarding clinical outcomes of a 2-week fractionation schedule , it was observed that acute and late effects were

acceptable with control rates similar to those reported in other trials with hypofractionation,Based

on these findings we started a trial to compare a 3-week radiotherapy schedule with a 2-week schedule .

Inclusion criteria

• Female patients aged ≥18 years.

Female or male patients with invasive carcinoma of the breast.

Complete microscopic excision of primary tumor.

Undergoing breast-conserving surgery (BCS) or modified radical mastectomy (MRM).

≥ Axillary lymph nodes dissected.

T1_4pN0_3M0 disease.

Neoadjuvant or adjuvant CTH .

Signed informed consent and able to comply with follow up.

Exclusion criteria

• Evidence of distant metastases.

Past history of malignancy.

Prior radiotherapy to the chest region

Simultaneous malignancy (except non-melanoma skin cancer or in situ cervical carcinoma)

Connective tissue diseases (e.g., lupus erythematosus, scleroderma)

Pregnancy or lactation