Short course hypofractionated whole breast irradiation after conservative surgery: A single institution phase II study

Background: to assess the oncologic outcomes of hypofractionated whole breast irradiation (hypo-wbi). methods: eligible patients had undergone breast conservative surgery for early breast cancer (ptis-2) and none/limited nodal involvement. hypo-wbi consisted of 34 gy in 10 daily fractions over 2 weeks to the whole breast three-dimensional conformal radiotherapy (3dcrt),followed by a single fraction of 8 gy to the tumor bed after 1 week (electrons). primary endpoint is freedom from ipsilateral breast tumor recurrence (ibtr). minimum follow up for living & event-free patients is 3 yrs.; median follow up time of the whole analyzed patient population is 5.4 yrs. (range: 1.8-11.4 yrs). results: two hundred fifty-one patients were accrued from 2004 to 2013. all patients underwent local excision of the primary tumor to negative margins. four patients failed in the ipsilateral breast after a median time of 3.2 years (range: 1.7-5.7 yrs) for a 5-year ibtr-free survival of 98.7% (95%ci: 97.3%-100%). ibtr-free survival was significantly higher for patients with invasive cancer than for patients with intraductal carcinoma (p = 0.036). within patients with invasive tumors,no clear trends or associations were detected between ibtr and age,grading,molecular subtype,pt or pn stage. at 5 years,the actuarial rates of gr2 fibrosis and gr2+ teleangectasia are 2.4% (95%ci: 0-6.5%) and 7.1% (95%ci: 0.4-13.7%),respectively. cosmesis was scored as excellent/good by ≈95% of patients and ≈60% of clinicians. conclusions: hypo-wbi in 3 weeks allows excellent oncologic outcomes for invasive breast cancer after conservative surgery. patients with intraductal carcinoma should be treated with hypo-wbi only within a controlled study. trial registration: ire-ifo ethical and scientific committee (cod. rs61/04). © 2017 the author(s).