Evidence map›Paper›PMID 42762384›Full record

ArticleBreast cancer (Tokyo, Japan)2026

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, Uhi Toh, Kenta Murotani, Ichiro Isomoto, Makoto Kubo, Reiki Nishimura, Yusaku Miyata, Gen Suzuki and 3 more

Abstract read
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In one paragraph

Article in Breast cancer (Tokyo, Japan), 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

0numbers the graph read from it
0cells of the map it votes in
0citing papers in PubMed
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1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

0 citing papers in PubMed.

No citing paper in PubMed yet.

4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

13 authors.

Etsuyo OgoRadiation Oncology Center, Kurume University, 67 Asahimachi, Kurume, Fukuoka, 830-0011, Japan. etsuogo@kurume-u.ac.jp.ORCID http://orcid.org/0000-0002-4909-0217
Takeshi ArimuraMedipolis Proton Therapy and Research Center, 4423 Higashikata Ibusuki, Kagoshima, 891-0304, Japan.
Takashi OginoMedipolis Proton Therapy and Research Center, 4423 Higashikata Ibusuki, Kagoshima, 891-0304, Japan.
Uhi TohDepartment of Breast Surgery, Kurume University, 67 Asahimachi, Kurume, Fukuoka, 830-0011, Japan.
Kenta MurotaniBiostatistic Center, Kurume University, 67 Asahimachi, Kurume, 830-0011, Fukuoka, Japan.
Ichiro IsomotoDepartment of Radiology, St. Francis Hospital, 9-20 Kominecyo, Nagasaki, 852-8125, Japan.
Makoto KuboDepartment of Breast Surgical Oncology/Clinical Genetics and Medicine, Kyushu University, 3-1-1 Maedashi, Higashiku, Fukuoka, 812-8582, Japan.
Reiki NishimuraDepartment of Breast Surgery, Sagara Hospital Miyazaki, 247-19 Shimoharamachi, Miyazaki, 880-0843, Japan.
Yusaku MiyataRadiation Oncology Center, Kurume University, 67 Asahimachi, Kurume, Fukuoka, 830-0011, Japan.
Gen SuzukiDepartment of Radiology, Kyoto Prefectural University of Medicine, 1-5 Shimogamohangicyo, Sakyouku, Kyoto, 606-0823, Japan.
Yoshio HishikawaMedipolis Proton Therapy and Research Center, 4423 Higashikata Ibusuki, Kagoshima, 891-0304, Japan.
Shoshu MitsuyamaDepartment of Breast and Thyroid Surgery, Kitakyushu Municipal Medical Center, 2-1-1 Bashaku, Kokurakitaku Kitakyushu, Fukuoka, 802-0077, Japan.
Ryoichi NagataMedipolis Medical Research Institute, 4423 Higashikata, Ibusuki, Kagoshima, 891-0304, Japan.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

backgroundWe report on our initial clinical experience with partial breast proton beam therapy (PB-PBT) without tumor resection as an alternative to partial mastectomy for low-risk early-stage breast cancer.

methodsThis trial commenced in 2015, and eligibility criteria included women with cT1N0M0 invasive ductal carcinoma, estrogen receptor positivity, human epidermal growth factor receptor type-2 negativity, age of 40-70 years, and a performance status of 0 or 1. In Phase I, PB-PBT was administered at 62.4 Gy (RBE) in 26 fractions using the field-in-field technique. After confirming that no serious adverse events occurred, Phase II was conducted using the same dose. Follow-up evaluations were conducted every 3 months for the first year after irradiation and every 6 months thereafter.

resultsAs of December 2025, 11 patients had completed a follow-up of ≥ 5 years. The median follow-up time was 82 months. Tumors exhibited immediate shrinkage post-PB-PBT, with morphological changes on ultrasonography and magnetic resonance imaging observed within 3-6 months. No recurrence was observed within the irradiated field in patients with > 5 years of follow-up. Dermatitis was Grade 1 in 55% of cases and Grade 2 in 45%; there were no cases of Grade ≥ 3. Grade 1 telangiectasia was observed in 36% of patients after 2 years, although most patients tolerated the treatment well.

conclusionPreliminary clinical observations suggest that PB-PBT without lumpectomy achieves results within specific criteria and that it could be an option for breast cancer treatment using radiation therapy alone.

Indexed as

Clinical trialCosmetic outcomesEarly-stage breast cancerPartial breast proton beam therapyWithout lumpectomy

Identifiers

PMID42762384

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.