Objective: To study the effect of post-mastectomy radiotherapy with different fractionated dose schemes for early breast cancer.
Methods: From January 1987 to January 1993, 367 patients with early breast cancer were given post-mastectomy radiotherapy with three different fractionated dose schemes. 149 patients received conventional radiotherapy with 50 Gy/25 fractions/5 weeks (Group A). 177 patients received 45 Gy/15 fractions/5 weeks (Group B). Forty-one patients were treated with 23 Gy/4 fractions/17 days (Group C). 257 patients received systemic therapy (chemotherapy and/or endocrine therapy).
Results: The overall 5-year survival and 5-year disease-free survival rates were 87.4% and 89.6%. The 5-year disease-free survival rate were 90.8%, 86.5% and 84.6% for A, B and C groups (P = 0.16). The corresponding loco-regional failure rates were 2.7%, 2.8% and 2.4%, respectively. There was no statistically significant difference in the local control and efficacy of the three groups.
Conclusion: With similar 5-year tumor-free survival rates by the conventional fractionation and hypofractionation, the scheme with 45 Gy/15 fractions/5 weeks has the advantage of giving less factions, which is suitable for a unit with limited radiation resources. The course of hypofractionation with 23 Gy/4 fractions/17 days is much shorter than conventional radiotherapy, which may benefit patients with higher risk of metastasis who need to undergo chemotherapy earlier. This study warrants further investigations.