Evidence map›Paper›PMID 42254623›Full record

ArticleFrontiers in public health2026

A study on the application of range shifter and bolus in spot-scanning proton arc (SPArc) therapy after modified radical mastectomy for left-sided breast cancer.

Linsen Zhou, Yiwen He, Shiyan Shen, Xiaobin Wang, Shuokai Jia, Hexiang Feng, Xinjian Yang, Xianhu Zeng

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Article in Frontiers in public health, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

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2 · The registry

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3 · Its place in the literature

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4 · The record

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5 · Who and what money

Authors and funding

8 authors.

Linsen ZhouSichuan University, Chengdu, China.
Yiwen HeSichuan University, Chengdu, China.
Shiyan ShenSichuan University, Chengdu, China.
Xiaobin WangSichuan University, Chengdu, China.
Shuokai JiaSichuan University, Chengdu, China.
Hexiang FengSichuan University, Chengdu, China.
Xinjian YangSichuan University, Chengdu, China.
Xianhu ZengDepartment of Radiotherapy Physics & Technology, West China Hospital, Sichuan University, Chengdu, Sichuan, China.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

Background: This study aimed to compare the dosimetric differences between the use of range shifter and bolus in spot-scanning proton arc (SPArc) therapy for postoperative radiotherapy after left-sided breast cancer modified radical mastectomy, with a primary focus on target volume dose coverage and organs-at-risk sparing. By comparison with VMAT, this study further explored the potential of SPArc to reduce the normal tissue complication probability (NTCP) and the effective dose to immune cells (EDIC). Methods: This retrospective study utilized the imaging datasets of 18 patients who treated with VMAT. Three SPArc plans were designed for each patient using the RayStation v2025: 1. SPArc with bolus (SPArcB); 2. SPArc with range shifter (SPArcR); 3. SPArc with both bolus and range shifter (SPArcRB). The target volumes included the supraclavicular target volume and the chest wall target volume. The Lyman-Kutcher-Birman NTCP model was adopted to evaluate pulmonary and cardiac toxicities and the EDIC model was applied to assess the immune cell dose across different plans. Robustness optimization accounting for a ± 3.5% range uncertainty and a 5 mm setup error was incorporated into all SPArc treatment plans. Results: All SPArc plans met robustness criteria and significantly reduced doses to the heart and left lung, as well as EDIC, compared to VMAT. The SPArcR plan demonstrated superior cardiac protection, achieving the lowest mean heart dose and the most significant reduction in NTCP for both the heart and lungs. While SPArcB showed a slight advantage in reducing the mean left lung dose, SPArcR yielded the highest conformity index for target coverage. Conclusion: This study confirms that, in postoperative radiotherapy for left-sided breast cancer after modified radical mastectomy, the standalone application of a range shifter can optimally reduce cardiac dose and the associated risk of complications while ensuring adequate target volume coverage, and it circumvents the issues of setup variability and hygiene concerns associated with the clinical use of bolus.

Indexed as

Mastectomy, Modified RadicalProton TherapyRadiotherapy, Intensity-ModulatedUnilateral Breast NeoplasmsAdultFemaleHumansMiddle AgedOrgans at RiskRadiotherapy DosageRadiotherapy Planning, Computer-AssistedRetrospective StudiesbolusEDICleft-sided breast cancerNTCPpostoperative radiotherapyrange shifterspot-scanning proton arc (SPArc) therapy

Identifiers

PMID42254623
PMCPMC13236887

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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.