Abstract:
Background: The current gold standard for adjuvant radiotherapy for breast cancer nowadays is hypofractionated radiotherapy. Measures for balancing both infectious and oncologic risk among patients and healthcare professionals must be carefully considered in the context of expected resource shortages and worldwide widespread community SARS-CoV-2 infection during the COVID- 19 pandemic. Here, we document the early and late skin toxicity and efficacy outcome of a prospective institutional phase III trial comparing a 1-week course of adjuvant breast radiotherapy to a 3-week regimen after surgical treatment for early breast cancer.
Methods: A phase III, randomized controlled trial is described here. Patients who underwent breast conserving surgery or a mastectomy and had invasive ductal or lobular breast cancer (pathological stagingT1-3, pN0-1, M0) were eligible if they were at least 18 years old. Sequential tumor bed boost radiotherapy (dose of 10 Gy/ 4 fractions and 5.2 Gy/ 1 fractions, respectively) is permitted in patients who have undergone breast conservative surgery and are younger than 50 years old and those of older age with high grade tumor or lymphovascular invasion. Patients were randomly assigned to receive 40 Gy/15 fractions (F)/3 weeks or 26 Gy/5 fractions (1 week). First endpoint evaluation of immediate and delayed effects on normal tissue and cosmetic results, Clinicians evaluated the impact on normal tissue using pictures, secondary endpoint estimation of two years LRR free survival, and two years disease free survival Results: At six weeks after the end of treatment, 65 patients in the control arm and 63 patients in the test arm were assessed for the most severe acute breast skin reactions. Grade 2 reactions, which were graded using CTCAE criteria (V4.03), were present in 47.7% of the control arm patients and 27% of the test arm patients, respectively.
Our study's assessment of the late effects on normal tissue after a median follow-up of 25 months, a range of 21 to 30 months, revealed that radiotherapy- related fibrosis, Telangiectasia, and hyperpigmentation were similar between the two groups (p>0.05), with fibrosis within the tumour bed being the most prevalent moderate or marked effect at 2 years, as occurred in 2 patients (3.1%) of 65 patients who received 40 Gy and 4 patients (6.3%) of 63 patients. Ultrahypofractionation resulted in incidence of excellent or good cosmesis over fair or poor cosmesis of 87.3% versus 12.7%, and the control arm resulted in a rate of 87.7% versus 12.3%, which is statistically insignificant (p=0.9). Two-year LRR-free survival was 96.9% in the control group and 98.4% in the ultrahypofractionation group, both of which were statistically insignificant. Of the two patients with LRR (3.1%) in the control arm and one (1.6%) patient in the ultrahypofractioation group, respectively, the disease-free survival rate was 95.3% in the control arm and 95.2% in the ultrahypofractioation arm.
Conclusion: 26 Gy in 5.2 Gy per fraction daily over 1 week is equal to 40.05 Gy in 2.67 Gy per fraction daily over 3 weeks for patients received adjuvant radiotherapy after surgical resection for early-stage breast cancer as regard normal tissue effects up to 2 years and for local tumor control and to confirm study result need longer follow up.
Keywords: Breast cancer, Ultrahypofractionation, Radiotherapy.