Yi An, MD
Associate Professor of Therapeutic RadiologyCards
About
Research
Publications
2026
Association Between Perirectal Spacer Use and Short-Term Complications Following Prostate Radiation Therapy in a National Claims Based Analysis.
Palencia P, Xi X, Zhao X, Ward B, Smani S, Sivanesan N, Diaz G, Miszczyk M, Fazekas T, Rajwa P, Cavallo J, Aneja S, An Y, Kim I, Leapman M. Association Between Perirectal Spacer Use and Short-Term Complications Following Prostate Radiation Therapy in a National Claims Based Analysis. Urology Practice 2026, 101097upj0000000000000996. PMID: 41810984, DOI: 10.1097/upj.0000000000000996.Peer-Reviewed Original ResearchProstate radiation therapyRectal toxicityTotal healthcare costsUrinary toxicityRadiation therapySpacer useSpacer placementAndrogen deprivation therapy useMultivariate Cox proportional hazards modelHealthcare costsUrinary tract infectionMonths of treatmentFDA-approved indicationsShort-term complicationsCox proportional hazards modelsOne-year incidenceClinical trial settingProportional hazards modelStatistically significant differenceGenitourinary toxicityProstate radiotherapyRadiotherapy modalitiesClaims-based studyProstate cancerTract infectionsEfficacy and tolerability of hypofractionated and dose-boosted radiotherapy for localised prostate cancer: a systematic review and meta-analysis
Miszczyk M, Sohoni N, Smani S, Moll M, Alfarhan A, Roessler N, Miyajima K, Inoue S, Marvaso G, Mastroleo F, Zamboglou C, Soeterik T, Zilli T, Terlizzi M, Blanchard P, Rajwa P, Fazekas T, Ploussard G, An Y, Leapman M, Blanck O, Jereczek-Fossa B, Shariat S. Efficacy and tolerability of hypofractionated and dose-boosted radiotherapy for localised prostate cancer: a systematic review and meta-analysis. Radiotherapy And Oncology 2026, 218: 111445. PMID: 41713502, DOI: 10.1016/j.radonc.2026.111445.Peer-Reviewed Original ResearchBiochemical recurrence-free survivalMetastasis-free survivalAdverse eventsOverall survivalRandomised controlled trialsProstate cancerClinically localised prostate cancerOpen-label study designRadiotherapy fractionation schedulesRecurrence-free survivalGenitourinary adverse eventsLocalised prostate cancerGastrointestinal adverse eventsHigh-risk patientsRate of gradeMeta-analysisSystematic reviewRandom-effects meta-analysesCochrane RoB 2 toolAcute gradeDose boostModerate hypofractionationUltra-hypofractionationBeam radiotherapyFocal boostFORMULA-509: A Multicenter Randomized Trial of Postprostatectomy Salvage Radiotherapy and 6 months of a GNRH Agonist with Either Bicalutamide or Abiraterone Acetate plus Prednisone and Apalutamide
Nguyen P, Kollmeier M, Rathkopf D, Hoffman K, Zurita A, Spratt D, Dess R, Liauw S, Szmulewitz R, Einstein D, Bubley G, Yu J, An Y, Wong A, Feng F, McKay R, Rose B, Shin K, Kibel A, Taplin M. FORMULA-509: A Multicenter Randomized Trial of Postprostatectomy Salvage Radiotherapy and 6 months of a GNRH Agonist with Either Bicalutamide or Abiraterone Acetate plus Prednisone and Apalutamide. European Urology 2026 PMID: 41672869, DOI: 10.1016/j.eururo.2025.12.001.Peer-Reviewed Original ResearchPSA progression-free survivalMetastasis-free survivalProstate-specific antigenSalvage radiotherapyMulticenter randomized trialGnRH agonistAbiraterone acetate plus prednisoneMetastasis-free survival ratesAcetate plus prednisoneProgression-free survivalMedian Follow-UpHigh-risk featuresStandard treatment optionDetectable prostate-specific antigenRadical prostatectomyAbiraterone acetatePN statusPrimary endpointSecondary endpointsSafety profileAdverse eventsTreatment optionsFollow-upApalutamidePreplanned analysis
2025
Association between perirectal spacer use and complications following prostate radiation therapy: Results of a national real-world data analysis.
Palencia P, Xi X, Zhao X, Smani S, Sivanesan N, Diaz G, Miszczyk M, Fazekas T, Rajwa P, Cavallo J, Aneja S, An Y, Kim I, Leapman M. Association between perirectal spacer use and complications following prostate radiation therapy: Results of a national real-world data analysis. JCO Oncology Practice 2025, 21: 571-571. DOI: 10.1200/op.2025.21.10_suppl.571.Peer-Reviewed Original ResearchRectal spacerProstate radiotherapyOne-year incidenceRadiation proctitisUrinary complicationsSpacer useAndrogen deprivation therapy useIncidence of radiation proctitisMultivariate Cox regression modelProstate radiation therapyUrinary tract infectionMonths of treatmentIncidence of hematuriaMarketScan Research DatabasesCox regression modelsUrinary toxicityRectal doseRadiation therapyGastrointestinal toxicityProstate cancerTract infectionsElixhauser Comorbidity IndexNo significant differenceRectal bleedingUrinary incontinenceAssociation between prostate radiotherapy and survival among patients with metastatic prostate cancer by extent of disease burden
Palencia P, Smani S, Zhao X, Kandala K, Sivanesan N, Cavallo J, Roessler N, Aneja S, An Y, Miszczyk M, Leapman M. Association between prostate radiotherapy and survival among patients with metastatic prostate cancer by extent of disease burden. Radiotherapy And Oncology 2025, 213: 111158. PMID: 40987387, DOI: 10.1016/j.radonc.2025.111158.Peer-Reviewed Original ResearchMetastatic prostate cancerProstate RTHormone therapyProstate cancerOverall survivalHazards regression modelsM1c diseaseProstate radiotherapySurvival outcomesHormone-sensitive metastatic prostate cancerRefinement of patient selectionSurvival outcomes of patientsObservational studyEra of molecular imagingObservational study of patientsNational Cancer DatabaseMultivariate proportional hazards regression modelSignificant OS benefitOutcomes of patientsKaplan-Meier curvesProportional hazards regression modelsStudy of patientsDistribution of stageRisk of deathM1b disease
2024
Testosterone Recovery and Associated Impact on Patient-Reported Health-Related Quality of Life (HRQoL) after Treatment with 6 Months of GnRH Agonist with or without Abiraterone Acetate plus Prednisone (AAP) and Apalutamide (Apa) in the FORMULA-509 Trial
Moningi S, Nguyen P, Rathkopf D, Zurita-Saavedra A, Spratt D, Dess R, Liauw S, Szmulewitz R, Einstein D, Bubley G, Yu J, An Y, Wong A, Feng F, Mckay R, Rose B, Shin K, Taplin M, Kollmeier M, Hoffman K. Testosterone Recovery and Associated Impact on Patient-Reported Health-Related Quality of Life (HRQoL) after Treatment with 6 Months of GnRH Agonist with or without Abiraterone Acetate plus Prednisone (AAP) and Apalutamide (Apa) in the FORMULA-509 Trial. International Journal Of Radiation Oncology • Biology • Physics 2024, 120: e563-e564. DOI: 10.1016/j.ijrobp.2024.07.1247.Peer-Reviewed Original ResearchMonths of GnRH agonistTestosterone recoveryGnRH agonistAssociated with lackClinically meaningful changeBaseline testosteroneAssociated with testosterone recoveryMedian Follow-UpEvaluated prior to treatmentTreatment groupsTrial randomized patientsHormonal functionPatient-reported health-related quality of lifeLog-rank testCompletion of treatmentMultivariate logistic regressionWilcoxon rank-sumPatient-reported HRQoL.Salvage radiationGleason scoreAbiraterone acetateHigher PSARecovery 1 yearRandomized patientsHealth-related quality of lifeLong-Term Patient-Reported Health-Related Quality of Life in the Randomized FORMULA-509 Trial of Salvage Radiotherapy and 6 Months of GnRH Agonist with Either Bicalutamide or Abiraterone Acetate Plus Prednisone and Apalutamide after Radical Prostatectomy
Hoffman K, Nguyen P, Rathkopf D, Zurita-Saavedra A, Spratt D, Dess R, Liauw S, Szmulewitz R, Einstein D, Bubley G, Yu J, An Y, Wong A, Feng F, Mckay R, Rose B, Lee K, Kibel A, Taplin M, Kollmeier M. Long-Term Patient-Reported Health-Related Quality of Life in the Randomized FORMULA-509 Trial of Salvage Radiotherapy and 6 Months of GnRH Agonist with Either Bicalutamide or Abiraterone Acetate Plus Prednisone and Apalutamide after Radical Prostatectomy. International Journal Of Radiation Oncology • Biology • Physics 2024, 120: s54. DOI: 10.1016/j.ijrobp.2024.07.088.Peer-Reviewed Original ResearchAbiraterone acetate plus prednisoneMonths of GnRH agonistAcetate plus prednisonePatient-reported health-related quality of lifeEPIC-26Hormonal functionHealth-related quality of lifeGnRH agonistTreatment armsTreatment to 1 yearQuality of lifeMental statusMetastasis-free survivalBaseline to endCompletion of treatmentSalvage radiationSalvage radiotherapyOncological outcomesRadical prostatectomyClinically meaningful differencesSaint Louis University Mental Status ExamNear baselineClinically meaningful declineT-scoreHormonal domainsAssociation Between the Decipher Genomic Classifier and Prostate Cancer Outcome in the Real-world Setting
Leapman M, Ho J, Liu Y, Filson C, Zhao X, Hakansson A, Proudfoot J, Davicioni E, Martin D, An Y, Seibert T, Lin D, Spratt D, Cooperberg M, Sprenkle P, Ross A. Association Between the Decipher Genomic Classifier and Prostate Cancer Outcome in the Real-world Setting. European Urology Oncology 2024, 8: 1101-1110. PMID: 39098389, DOI: 10.1016/j.euo.2024.07.010.Peer-Reviewed Original ResearchDecipher genomic classifierRisk of metastasisBiochemical recurrenceRadical prostatectomyGenomic classifierDecipher testProstate cancerProstate Risk Assessment Postsurgical ScoreRisk of biochemical recurrencePatient's prostate cancerRisk of cancer recurrencePathological risk factorsProstate cancer outcomesCox proportional hazards regressionRetrospective cohort studyElectronic health record dataReal-world settingsProportional hazards regressionHealth record dataReal-world practice settingsProstate biopsyRP specimensOncological outcomesPrognostic significanceMedian ageDevelopment of a Longitudinal Prostate Cancer Transcriptomic and Clinical Data Linkage
Leapman M, Ho J, Liu Y, Filson C, Zhao X, Hakansson A, Proudfoot J, Davicioni E, Martin D, An Y, Seibert T, Lin D, Spratt D, Cooperberg M, Ross A, Sprenkle P. Development of a Longitudinal Prostate Cancer Transcriptomic and Clinical Data Linkage. JAMA Network Open 2024, 7: e2417274. PMID: 38874922, PMCID: PMC11179136, DOI: 10.1001/jamanetworkopen.2024.17274.Peer-Reviewed Original ResearchConceptsElectronic health recordsCancer diagnosisClinical data linkageMedicine Clinical TermsPatterns of careProstate cancer diagnosisRadical prostatectomyCancer risk stratificationData linkageHealth recordsClinical dataMain OutcomesCancer outcomesClinical juncturesClinical careCommon Procedural Terminology codesAdministrative dataDiagnosis codesLongitudinal clinical dataCohort studyPharmacy recordsGenomic classifierProcedural Terminology codesDevelopment of prostate cancer metastasisLinkage dataSynthetic cationic helical polypeptides for the stimulation of antitumour innate immune pathways in antigen-presenting cells
Lee D, Huntoon K, Wang Y, Kang M, Lu Y, Jeong S, Link T, Gallup T, Qie Y, Li X, Dong S, Schrank B, Grippin A, Antony A, Ha J, Chang M, An Y, Wang L, Jiang D, Li J, Koong A, Tainer J, Jiang W, Kim B. Synthetic cationic helical polypeptides for the stimulation of antitumour innate immune pathways in antigen-presenting cells. Nature Biomedical Engineering 2024, 8: 593-610. PMID: 38641710, PMCID: PMC11162332, DOI: 10.1038/s41551-024-01194-7.Peer-Reviewed Original ResearchAntigen-presenting cellsInnate immune pathwaysImmune pathwaysPriming of effector T cellsImmune checkpoint inhibitorsAntitumour immune responseEffector T cellsIntracellular DNA-sensing pathwaysMetastatic breast cancerSyngeneic mouse modelMultiple innate immune pathwaysAdaptive immunogenicityAntitumour responseCheckpoint inhibitorsEndoplasmic reticulum stressT cellsSystemic clearanceBreast cancerDNA-sensing pathwayRelease of mitochondrial DNATherapeutic advantageMouse modelImmune responseEfficient primingIntracellular delivery
Clinical Trials
Current Trials
Phase II Trial Of Stereotactic Body Radiation Therapy (SBRT) for Oligoprogression on Immune Checkpoint Inhibitors (ICI) in Metastatic Renal Cell Carcinoma
IRB ID2000027702RoleSub InvestigatorPrimary Completion Date10/01/2025Recruiting Participants
Academic Achievements & Community Involvement
Clinical Care
Overview
Yi An, MD, is a radiation oncologist in the Department of Therapeutic Radiology at Yale Medicine. He specializes in treating head and neck, gastrointestinal, prostate and lung cancers.
“I am so fortunate to have the privilege of taking care of cancer patients,”
Dr. An says. “Every day, I have the special opportunity to get to know and form lasting relationships with my patients.” Dr. An is trained in modern radiation treatment techniques, including intensity-modulated radiation therapy, stereotactic body radiation therapy and stereotactic radiosurgery. These cutting-edge radiation techniques, Dr. An says, can target and destroy cancer cells while also minimizing radiation doses to normal tissue and reduce the risk of side effects of treatment.
“Being with my patients at perhaps their most trying time in life,” he says, “drives me to do everything possible to cure their disease and alleviate their pain.”
At Yale School of Medicine, Dr. An is an assistant professor of therapeutic radiology.
Clinical Specialties
Prostate & Genitourinary Radiotherapy; Urologic Oncology; Neuro-Oncology
Fact Sheets
Gastrointestinal Cancers
Learn More on Yale MedicineRadiofrequency Ablation (RFA)
Learn More on Yale MedicineMetastatic Brain Tumors
Learn More on Yale MedicineRhabdomyosarcoma
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Yale Medicine News
News
News
- March 23, 2026
Yale Launches Innovative Clinical Trial for Metastatic Bladder Cancer
- November 19, 2024
2nd Annual Yale Urology Bulldog Debates Recap
- June 18, 2024
Combined Data Speak Volumes for Prostate Cancer Treatment
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