Ultrahypofractionated partial breast irradiation following oncoplastic surgery: secondary analysis of a phase II trial.

Summary

In a prospective phase II cohort (50 patients, 52 tumors), ultrahypofractionated PBI after oncoplastic surgery achieved comparable dosimetry, excellent long-term aesthetic scores, and no local recurrences at a median 46 months when guided by MRI, seroma, and clips. The data support safe PBI use post-oncoplastic reconstruction in selected low-risk patients.

Key Findings

• Among 50 patients (52 tumors), 48% underwent oncoplastic reconstruction; no significant dosimetric differences vs standard lumpectomy (p > 0.05).
• Long-term BCTOS aesthetic scores converged between groups (>2 years: 1.29 vs 1.35; p = 0.71).
• No local recurrences at median 46 months follow-up.
• MRI, seroma, and surgical clips facilitated robust target delineation despite tissue rearrangement.

Clinical Implications

For low-risk early breast cancer with oncoplastic reconstruction, PBI (30 Gy in 5 fractions) can be considered when imaging and surgical markers allow confident target definition; counsel patients that cosmesis is maintained and may improve over time.

Limitations

• Single-arm secondary analysis with modest sample size; potential selection bias.
• Heterogeneity in oncoplastic techniques and target volume definitions may limit generalizability.

Future Directions

Randomized or matched comparative studies versus whole-breast irradiation and across oncoplastic techniques; incorporate cosmetic photography, objective fibrosis/edema metrics, and long-term oncologic endpoints.