{"doi":"10.1016/j.adro.2023.101334","title":"Five-Year Outcomes of a Phase 1/2 Trial of Accelerated Partial Breast Irradiation Using Proton Therapy for Women With Stage 0-IIA Breast Cancer","abstract":"Purpose: We report the results of a phase 1/2 trial of external beam partial breast radiation using proton therapy. Methods and Materials: Eligible patients included stage 0-IIA breast cancer pTis-T2, N0, and size ≤3 cm. Proton beam radiation was used to deliver 3.85 Gy twice daily to 38.5 Gy. The phase 1 portion determined feasibility based on criteria of successful plan creation, treatment delivery, and acute toxicity grade ≥3 in ≤20% of patients. The phase 2 portion had efficacy goals of acute toxicity grade ≥3 in ≤20% of patients and observing physician-rated cosmesis of excellent or good >85% of patients at 2 years. Results: From April 2013 to March 2015, there were 12 patients enrolled onto the phase 1 portion, and the preplanned analysis of feasibility was met in all 4 required criteria. From July 2015 through December 2019 there were 28 patients with 29 treated breasts (1 bilateral) enrolled onto the phase 2 portion of the trial out of 45 originally planned. The trial was closed to accrual because of the coronavirus pandemic and not reopened. Thirty-eight breasts were treated with double-scattering and 3 pencil-beam scanning protons. The median follow-up of the 40 patients is 5.4 years (range, 2.3-8.6 years). There was 1 local recurrence. There was no grade ≥3 acute or late toxicity. At baseline all patients had physician-rated cosmesis good or excellent but at 2 years was excellent in 56%, good in 19%, and fair in 25%. Conclusions: Proton-accelerated partial breast irradiation delivered with a twice-daily fractionation was feasible and associated with very low acute and long-term toxicity. However, the trial did not meet goals for cosmesis outcomes and was closed prematurely. Future study is needed to determine whether pencil-beam scanning protons or different fractionation could improve these outcomes.","journal":"Advances in Radiation Oncology","year":2023,"id":383564,"datarank":0.0,"base_score":0.0,"endowment":0.0,"self_citation_contribution":0.0,"citation_network_contribution":0.0,"self_endowment_contribution":0.0,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":2,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9115,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2023-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":1143528,"name":"Taoran Li","orcid":"0000-0001-7180-4258","position":1,"is_corresponding":false},{"id":1151015,"name":"E Garver","orcid":null,"position":2,"is_corresponding":false},{"id":1151016,"name":"Katherine Shillington","orcid":null,"position":3,"is_corresponding":false},{"id":1151017,"name":"B. Shinkle","orcid":null,"position":4,"is_corresponding":false},{"id":256200,"name":"Julia Tchou","orcid":"0000-0002-2032-1579","position":5,"is_corresponding":false},{"id":347343,"name":"Oluwadamilola M. Fayanju","orcid":"0000-0002-0876-975X","position":6,"is_corresponding":false},{"id":235191,"name":"Lilie L. Lin","orcid":"0000-0001-7681-8966","position":7,"is_corresponding":false},{"id":372400,"name":"Neil K. Taunk","orcid":"0000-0002-1349-9774","position":8,"is_corresponding":false},{"id":1150648,"name":"Gary M. Freedman","orcid":"0000-0001-9478-4798","position":0,"is_corresponding":true}],"reference_count":19,"raw_metadata":null,"created_at":"2026-07-19T01:17:29.050285Z","pmid":"38405317","pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}