Resource implications of evolving breast cancer radiotherapy treatment protocols.

• Updated breast cancer adjuvant radiotherapy treatment protocols resulted in a reduction of staff time (linac and non-linac) and overall resource costs. • The introduction of ultrahypofractionated 26Gy/5 radiotherapy resulted in the greatest saving of resource costs, €47,489, and staff time, 13,820 min. • Expanded use of IMN radiotherapy resulted in the largest increase in resource costs, €7,612, and staff time, 11,345 min. • After implementing all treatment protocols changes, the overall resource cost was reduced by €62,477 (11.5 %). • Overall linac time was reduced by 9700 min (12.9 %) and non-linac time was reduced by 1315 min (1.1 %).