Five-year outcomes of partial breast proton beam therapy without lumpectomy for early-stage breast cancer: an interventional prospective study.
Etsuyo Ogo, Takeshi Arimura, Takashi Ogino et al.
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In 30 seconds
This prospective interventional clinical trial evaluated partial breast proton beam therapy (PB-PBT) without tumor resection in women aged 40–70 years with low-risk, early-stage, estrogen receptor-positive, HER2-negative cT1N0M0 invasive ductal carcinoma. Treatment was 62.4 Gy (RBE) in 26 fractions. Among 11 patients with at least 5 years of follow-up (median 82 months), no recurrence was observed within the irradiated field. The authors describe these findings as preliminary and suggest radiation therapy alone may be an option for selected patients.
Key findings
- No recurrence within the irradiated field was observed among patients with more than 5 years of follow-up.
- Among 11 patients followed for at least 5 years, median follow-up was 82 months.
- Dermatitis was Grade 1 in 55% and Grade 2 in 45%; no Grade ≥ 3 dermatitis occurred.
- Grade 1 telangiectasia was observed in 36% of patients after 2 years.
Why it matters
The study provides prospective long-term observations on a breast-conserving approach that omits lumpectomy in a narrowly defined, low-risk population. The absence of in-field recurrence in the reported follow-up is encouraging, while the small number of patients and preliminary nature of the findings mean that the results should be interpreted cautiously.
What to keep in mind
Only 11 patients had completed at least 5 years of follow-up, and the study reports preliminary observations in a selected low-risk population.