Lower incidence of sexual dysfunction associated with stereotactic radiosurgery using CyberKnife in prostate cancer patients: initial results

Menor incidencia de disfunción sexual asociada a la radiocirugía estereotáctica con CyberKnife en pacientes con cáncer de próstata: resultados iniciales

Background: Prostate cancer is among the most prevalent oncological diseases globally, and its management must prioritize both effectiveness and quality of life. Although advancements in prostatectomy techniques have improved outcomes, many patients still face a decline in sexual function post-surgery. The advent of early screening via prostate-specific antigen (PSA) testing and technological innovations in radiotherapy have introduced radiosurgery as a viable alternative for treating low- and intermediate-risk prostate cancer, with the added benefit of reduced toxicity. Methods: At our clinic, patients are treated with Stereotactic Body Radiation Therapy (SBRT) using the CyberKnife system, with a specific focus on preserving erectile function. The treatment protocol involves precise patient immobilization, anatomotopographic planning using Magnetic Resonance Imaging-Computed Tomography (MRI-CT) fusion imaging, a fixed radiation dose to the prostate, and strict adherence to dose limitations for surrounding critical structures. Results: Biochemical control is evaluated by monitoring PSA levels within one year post-treatment. In addition, patient-reported outcomes are assessed using the Expanded Prostate Cancer Index Composite (EPIC-26) questionnaire. This tool is administered prior to the first session and periodically during the year following treatment to track side effects and quality-of-life indicators, particularly in relation to sexual and urinary functions. Conclusions: CyberKnife-based SBRT represents an effective and patient-centered approach to prostate cancer treatment. It enables targeted tumor control while aiming to minimize adverse effects, especially those impacting sexual health. Early results indicate favorable biochemical control and tolerable side effects, supporting its use as an alternative to more invasive procedures for selected patients.

Resumen

Antecedentes: El cáncer de próstata es una de las enfermedades oncológicas más prevalentes a nivel mundial, y su tratamiento debe priorizar tanto la efectividad como la calidad de vida. Aunque los avances en las técnicas de prostatectomía han mejorado los resultados, muchos pacientes aún experimentan una disminución en la función sexual tras la cirugía. La introducción del cribado temprano mediante el antígeno prostático específico (PSA) y los avances tecnológicos en radioterapia han posicionado a la radiocirugía como una alternativa viable para el tratamiento del cáncer de próstata de bajo y riesgo intermedio, con el beneficio adicional de una menor toxicidad. Métodos: En nuestra clínica, los pacientes son tratados mediante Radioterapia Corporal Estereotáctica (SBRT) con el sistema CyberKnife, con un enfoque específico en la preservación de la función eréctil. El protocolo de tratamiento incluye una inmovilización precisa del paciente, planificación anatomotopográfica mediante fusión de imágenes de resonancia magnética nuclear (RMN) y tomografía computarizada (TC), una dosis fija administrada a la próstata, y un estricto cumplimiento de los límites de dosis a los órganos críticos circundantes. Resultados: El control bioquímico se evalúa mediante el seguimiento de los niveles de PSA durante el primer año posterior al tratamiento. Además, se analizan los resultados reportados por los pacientes mediante el cuestionario Expanded Prostate Cancer Index Composite (EPIC-26). Esta herramienta se aplica antes del inicio del tratamiento y periódicamente durante el año posterior, para valorar los efectos secundarios y los indicadores de calidad de vida, en especial aquellos relacionados con las funciones sexual y urinaria. Conclusiones: La SBRT con CyberKnife representa un enfoque eficaz y centrado en el paciente para el tratamiento del cáncer de próstata. Permite un control tumoral preciso y busca minimizar los efectos adversos, especialmente los que afectan la salud sexual. Los resultados preliminares muestran un control bioquímico favorable y efectos secundarios tolerables, respaldando su uso como alternativa a procedimientos más invasivos en pacientes seleccionados.

Prostate cancer; CyberKnife; Erectile function; EPIC-26 questionnaire; Quality of life

Palabras Clave

Cáncer de próstata; CyberKnife; Función erectile; Cuestionario EPIC-26; Calidad de vida

[1] Siegel RL, Miller KD, Fuchs HE, Jemal A. Cancer statistics, 2021. CA: A Cancer Journal for Clinicians. 2021; 71: 7–33.

[2] Young HH. The early diagnosis and radical cure of carcinoma of the prostate. Being a study of 40 cases and presentation of a radical operation which was carried out in four cases. Bulletin of the John Hopkins Hospital. 1905; 16: 315–321.

[3] Walsh PC, Donker PJ. Impotence following radical prostatectomy: insight into etiology and prevention. Journal of Urology. 1982; 128: 492–497.

[4] Popiołek A, Brzoszczyk B, Jarzemski P, Piskunowicz M, Jarzemski M, Borkowska A, et al. Quality of life of prostate cancer patients undergoing prostatectomy and affective temperament. Cancer Management and Research. 2022; 14: 1743–1755.

[5] American Society for Radiation Oncology (ASTRO). ASTRO model policy: stereotactic body radiation therapy (SBRT). 2013. Available at: https://www.astro.org/ASTRO/media/ASTRO/Daily%20Practice/PDFs/ASTROSBRTModelPolicy.pdf (Accessed: 10 May 2025).

[6] National Comprehensive Cancer Network (NCCN). NCCN clinical practice guidelines in oncology: prostate cancer. 2015. Available at: https://www2.tri-kobe.org/nccn/guideline/archive/urological2016-2017/english/prostate.pdf (Accessed: 10 May 2025).

[7] King CR, Collins S, Fuller D, Wang PC, Kupelian P, Steinberg M, et al. Health-related quality of life after stereotactic body radiation therapy for localized prostate cancer: results from a multiinstitutional consortium of prospective trials. International Journal of Radiation Oncology, Biology, Physics. 2013; 87: 939–945.

[8] Grahvendy M, Brown B, Wishart LR. A pilot study on the collection of adverse event data from the patient using an electronic platform in a cancer clinical trial unit. Drugs-Real World Outcomes. 2024; 11: 725–734.

[9] Minasian LM, O'Mara A, Mitchell SA. Clinician and patient reporting of symptomatic adverse events in cancer clinical trials: using CTCAE and PRO-CTCAE® to provide two distinct and complementary perspectives. Patient Related Outcome Measures. 2022; 13: 249–258.

[10] Nyongole O, Kakoko D, Sirili N, Frumence G, Simba D, Urassa D, et al. Patients’ perception on quality of care for prostate cancer at tertiary hospitals in Tanzania: a qualitative study. Frontiers in Oncology. 2024; 14: 1492302.

[11] Leuteritz K, Richter D, Mehnert-Theuerkauf A, Stolzenburg JU, Hinz A. Quality of life in urologic cancer patients: importance of and satisfaction with specific quality of life domains. Quality of Life Research. 2022; 31: 759–767.

[12] Culakova E, Mohamed M, Flannery M, Jensen-Battaglia M, Zhang Z, Ramsdale E, et al. Relationships between patient-reported and clinician-rated toxicities and daily functioning in older adults with advanced cancer undergoing systemic therapy. Cancer. 2025; 131: e35766.

[13] Butcher NJ, Monsour A, Mew EJ, Chan AW, Moher D, Mayo-Wilson E, et al. Guidelines for reporting outcomes in trial reports: the CONSORT-outcomes 2022 extension. JAMA. 2022; 328: 2252–2264.

[14] Sanda M, Wei JT, Litwin MS. Scoring instructions for the Expanded Prostate cancer Index Composite short form (EPIC-26). 2002. Available at: https://medicine.umich.edu/sites/default/files/content/downloads/Scoring%20Instructions%20for%20the%20EPIC%2026.pdf (Accessed: 01 September 2022).

[15] Valli J, Haapiainen H, Murtola TJ, Huhtala H, Kaipia A, Raitanen M. Visual analogue scale and expanded prostate cancer index composite-26 in the evaluation of urinary continence recovery after three-dimensional laparoscopic radical prostatectomy, a single-center prospective registered study. Urology. 2023; 177: 103–108.

[16] Movsas B, Hunt D, Watkins-Bruner D, Lee WR, Tharpe H, Goldstein D, et al. Can electronic web-based technology improve quality of life data collection? Analysis of radiation therapy oncology group 0828. Practical Radiation Oncology. 2014; 4: 187–191

[17] Borzillo V, Scipilliti E, Pezzulla D, Serra M, Ametrano G, Quarto G, et al. Stereotactic body radiotherapy with CyberKnife® system for low- and intermediate-risk prostate cancer: clinical outcomes and toxicities of CyPro Trial. Frontiers in Oncology. 2023; 13: 1270498.

[18] Kilby W, Dooley JR, Kuduvalli G, Sayeh S, Maurer CR Jr. The CyberKnife Robotic Radiosurgery system in 2010. Technology in Cancer Research & Treatment. 2010; 9: 433–452.

[19] Brenner DJ, Martinez AA, Edmundson GK, Mitchell C, Thames HD, Armour EP. Direct evidence that prostate tumors show high sensitivity to fractionation (low alpha/beta ratio), similar to late-responding normal tissue. International Journal of Radiation Oncology, Biology, Physics. 2002; 52: 6–13.

[20] Stewart AJ, Chargari C, Chyrek A, Eckert F, Guinot JL, Hellebust TP, et al. Radiobiology and modelling in Brachytherapy: a review inspired by the ESTRO Brachytherapy pre-meeting course. Clinical and Translational Radiation Oncology. 2024; 50: 100885.

[21] Cozzi S, Lazrek A, Rubini G, Rubini D, Sardaro A, Houabes S, et al. Single-dose radiation therapy for localized prostate cancer: where does the evidence lead? Cancers. 2025; 17: 1176.

[22] Dejonckheere CS, Caglayan L, Glasmacher AR, Wiegreffe S, Layer JP, Nour Y, et al. Prostate-specific antigen kinetics after stereotactic body radiotherapy for localized prostate cancer: a scoping review and meta-analysis. Radiotherapy and Oncology. 2025; 202: 110642.

[23] Talvitie AM, Helminen M, Ojala H, Tammela T, Auvinen A, Pietilä I. Missingness in the expanded prostate cancer index short form (EPIC-26)—prevalence, patterns, and explanatory factors. Health and Quality of Life Outcomes. 2023; 21: 89.

[24] Mark KP, Arenella K, Girard A, Herbenick D, Fu J, Coleman E. Erectile dysfunction prevalence in the United States: report from the 2021 National Survey of Sexual Wellbeing. The Journal of Sexual Medicine. 2024; 21: 296–303.

[25] Yamashita H, Ogita M, Sawayanagi S, Nozawa Y, Abe O. Quality of life after definitive linear accelerator-based stereotactic radiotherapy for prostate cancer: a longitudinal study. Radiation Oncology. 2022; 17: 90.