{"doi":"10.1016/j.phro.2025.100715","title":"Optimal timing of organs-at-risk-sparing adaptive radiation therapy for head-and-neck cancer under re-planning resource constraints","abstract":"Background and purpose: Prior work on adaptive organ-at-risk (OAR)-sparing radiation therapy has typically reported outcomes based on fixed-number or fixed-interval re-planning, which represent one-size-fits-all approaches and do not account for the variable progression of individual patients' toxicities. The purpose of this study was to determine the personalized optimal timing of re-planning in adaptive OAR-sparing radiation therapy, considering limited re-planning resources, for patients with head and neck cancer (HNC). Materials and methods: A novel Markov decision process (MDP) model was developed to determine optimal timing of re-planning based on the patient's expected toxicity, characterized by normal tissue complication probability (NTCP), for four toxicities. The MDP parameters were derived from a dataset comprising 52 HNC patients treated between 2007 and 2013. Kernel density estimation was used to smooth the sample distributions. Optimal re-planning strategies were obtained when the permissible number of re-plans throughout the treatment was limited to 1, 2, and 3, respectively. Results: The MDP (optimal) solution recommended re-planning when the difference between planned and actual NTCPs (ΔNTCP) was greater than or equal to 1%, 2%, 2%, and 4% at treatment fractions 10, 15, 20, and 25, respectively, exhibiting a temporally increasing pattern. The ΔNTCP thresholds remained constant across the number of re-planning allowances (1, 2, and 3). Conclusion: In limited-resource settings that impeded high-frequency adaptations, ΔNTCP thresholds obtained from an MDP model could derive optimal timing of re-planning to minimize the likelihood of treatment toxicities.","journal":"Physics and Imaging in Radiation Oncology","year":2025,"id":551345,"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":1,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9564,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2025-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":659027,"name":"Cem Dede","orcid":"0000-0002-0543-9325","position":1,"is_corresponding":false},{"id":1013167,"name":"Lucas McCullum","orcid":"0000-0001-9788-7987","position":2,"is_corresponding":false},{"id":1283199,"name":"Raúl García","orcid":"0000-0003-1559-6612","position":3,"is_corresponding":false},{"id":351182,"name":"Abdallah Mohamed","orcid":"0000-0003-2064-7613","position":4,"is_corresponding":false},{"id":261754,"name":"Jacob G. Scott","orcid":"0000-0003-2971-7673","position":5,"is_corresponding":false},{"id":430416,"name":"James E. Bates","orcid":"0000-0001-7060-7156","position":6,"is_corresponding":false},{"id":636231,"name":"Brigid A. McDonald","orcid":"0000-0003-4230-1330","position":7,"is_corresponding":false},{"id":519105,"name":"Kareem A. Wahid","orcid":"0000-0002-0503-0175","position":8,"is_corresponding":false},{"id":653657,"name":"Mohamed A. Naser","orcid":"0000-0003-1020-4966","position":9,"is_corresponding":false},{"id":426705,"name":"Renjie He","orcid":"0000-0001-9166-6286","position":10,"is_corresponding":false},{"id":1283198,"name":"Aysenur Karagoz","orcid":"0000-0002-9232-2984","position":11,"is_corresponding":false},{"id":346829,"name":"Amy C. Moreno","orcid":"0000-0001-6762-6807","position":12,"is_corresponding":false},{"id":103919,"name":"Lisanne V. van Dijk","orcid":"0000-0002-9515-5616","position":13,"is_corresponding":false},{"id":310388,"name":"Kristy K. Brock","orcid":"0000-0001-9364-5040","position":14,"is_corresponding":false},{"id":1332685,"name":"Jolien Heukelom","orcid":"0000-0001-8042-5401","position":15,"is_corresponding":false},{"id":1235305,"name":"Seyedmohammadhossein Hosseinian","orcid":"0000-0001-7016-5925","position":16,"is_corresponding":false},{"id":1026560,"name":"Mehdi Hemmati","orcid":"0000-0002-0560-3893","position":17,"is_corresponding":false},{"id":1235306,"name":"Andrew J. Schaefer","orcid":"0000-0002-0379-741X","position":18,"is_corresponding":false},{"id":295555,"name":"Clifton D. Fuller","orcid":"0000-0002-5264-3994","position":19,"is_corresponding":false},{"id":1283200,"name":"Fatemeh Nosrat","orcid":"0009-0009-2043-7115","position":0,"is_corresponding":true}],"reference_count":48,"raw_metadata":null,"created_at":"2026-07-19T02:54:25.065895Z","pmid":"40123771","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":[]}