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Main Session

SS 38 - GU 2: Optimizing the Therapeutic Ratio in Prostate Cancer

319 - Dose Escalated Pelvic Lymph Node Intensity Modulated Radiation Therapy (IMRT) with a Simultaneous Hypofractionated Boost to the Prostate for NCCN Very-High Risk Adenocarcinoma of the Prostate, a Prosp

Tuesday, October 1, 2024
4:20 PM – 4:30 PM ET
Location: Room 202

    Presenter(s)

  • William Hall, MD

    Medical College of Wisconsin (MCW)
    Elm Grove, WI, United States

W. A. Hall1, F. Chunara2, A. Banerjee3, M. Bedi2, D. Kilari2, K. A. Bylow2, J. Burfeind2, A. D. Currey1, K. Jacobsohn2, A. Nelson2, S. Johnson2, J. M. Longo2, M. W. Straza Jr4, and C. A. F. Lawton1; 1Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, WI, 2Medical College of Wisconsin, Milwaukee, WI, 3Department of Biostatistics, Medical College of Wisconsin, Milwaukee, WI, 4Department of Radiation Oncology, Froedtert & the Medical College of Wisconsin, Milwaukee, WI

Purpose/Objective(s): There remains limited data as to the efficacy of higher doses of elective radiation therapy (RT) to the pelvic lymph nodes for men with very high risk, non-metastatic adenocarcinoma of the prostate. We conducted a prospective phase II study to evaluate the toxicity and efficacy of external beam dose escalation to the pelvic lymph nodes using a simultaneous integrated boost (SIB) to the prostate. We report the long-term clinical outcomes of a prospective phase II clinical trial (NCT02177292) with a median follow up of over 10 years.

Materials/

Methods: Patients were eligible with biopsy proven adenocarcinoma of the prostate, a probability of lymph node risk of at least 25%, Karnofsky Performance Scale of at least 70, and no evidence of M1 disease. Acute and late toxicity were prospectively collected at each follow up using CTCAE version 4.0. Pelvic lymph nodes were treated to a dose of 56 Gy over 28 fractions with a simultaneous integrated boost (SIB) to the prostate to a total dose of 70 Gy over 28 fractions using IMRT. Patients were followed every three months for the first two years, every 6 months from years three to five, and annually. All patients received neoadjuvant, concurrent, and adjuvant androgen deprivation therapy for a median of 24 months. Secondary to the time frame of the study accrual, PSMA pet was not available. Descriptive statistics, including mean and inter-quartile ranges for all continuous variables, such as age and PSA and frequencies for all categorical variables were computed. Survival statistics were computed using the Kaplan Meier method.


Results: 80 patients were prospectively enrolled with 78 patients deemed eligible after final review. The mean patient age at biopsy was 72 (57-86), mean pre-treatment PSA was 19.01 (2.6-111.5), median T stage was T2c (T1c-T3b), 69.2% (54/78) patients had a Gleason score of 9, 28% had a Gleason score of 8. 84% of patients were classified as NCCN very high risk. At a median follow up of 10.6 years biochemical control was achieved in 92.5% of patients, distant metastasis free survival was 96.2%. Cumulative rates of all grade 2 or higher late toxicity (attributable and non-attributable to RT) was 38%, the majority of patients (62%) had grade 1 or lower toxicity.


Conclusion: Nodal RT dose escalation in a modern prospective cohort of NCCN very high-risk prostate cancer resulted in extremely promising 10-year clinical outcomes. Radiation dose intensification to the pelvic nodes warrants further study and consideration for further testing in randomized phase III clinical trials.