Evaluation of Tumor Control Based on Serial Multiparametric MRI and Post-Treatment Biopsies For Patients Treated With Dose Intensification to the Dominant Intra-Prostatic Lesion (DIL) Using Ultra-Hypofractionated, MR-Guided Radiotherapy

NYU Langone Health

Status: Enrolling

Conditions: Prostate Cancer

Treatments: Radiation: 1.5 T Elekta Unity MR-Linac system; Device: Hydrogel rectal spacer (SpaceOAR)

Study type: Interventional

Funder types: Other

Identifiers

NCT06542757

23-01590

Details and patient eligibility

About

The purpose of this study is to assess the impact of this MR-guided radiotherapy on tumor control of the dominant intraprostatic lesion among patients with intermediate risk prostate cancer. This study of Radiotherapy to the Prostate and Dominant Lesion Using Ultra-Hypofractionated, MR-adaptive Radiation Therapy aims to evaluate tumor control after definitive ultra-hypofractionated external beam radiation therapy (including a simultaneously delivered high-dose boost to a dominant lesion as detected on prostate magnetic resonance imaging (MRI)) in patients with intermediate-risk prostate cancer. This will incorporate the use of multiparametric MRI for target segmentation and the use of the MR-linac with adaptive radiation planning to treat the prostate gland, incorporating a dose boost to the dominant intraprostatic lesion (DIL) that is visible on T2-weighted and diffusion-weighted imaging and de-escalation of dose to the remainder of the prostate.

Enrollment: 91 estimated patients

Sex: Male

Ages: 18+ years old

Volunteers: No Healthy Volunteers

Inclusion criteria

1. Intermediate-risk prostate cancer patients will be eligible for this study. Risk groups will be assigned as per National Comprehensive Cancer Network (NCCN) guidelines. Intermediate-risk patients will be defined as:

   • PSA 10-20 ng/ml or
   • Gleason score = 7 or
   • Clinical stage T2b/T2c (T2b: the tumor has spread to more than one-half of one side of the prostate, but not to both sides. T2c: the cancer has invaded both sides of the prostate)

2. Age > 18

3. Karnofsky Performance Status (KPS) > 80

4. Prostate size < 90 cc

5. Presence of a T2-visible prostatic lesion with maximum dimension of ≥ 0.5 cm and no more than two additional disease foci with a documented Prostate Imaging Reporting and Data System (PIRADS) 4-5 lesion

6. MRI findings: Lesion may contact the capsular edge, possible extracapsular extension (ECE) permitted

7. International Prostate Symptom Score < 18

8. Satisfy all MRI screening criteria and be willing to fill out the standard MRI screening form

Exclusion criteria

1. Gleason score >7

2. PSA >20 ng/mL

3. Prior or concurrent androgen deprivation therapy for prostate cancer

4. MRI findings: suspicious for/probable ECE

5. MRI findings: >2 disease foci identifiable

6. Evidence of metastatic disease on bone scan or MRI/CT

7. MRI ineligibility due to: the presence of a cardiac pacemaker, defibrillator, or other implanted metallic or electronic device which is considered MR unsafe; severe claustrophobia; inability to lie flat for the duration of the study; etc.

8. Metallic implant or device in the pelvis that might distort the local magnetic field and compromise quality of mp-MRI

9. Lateral pelvic separation greater than 50 cm and/or anterior-posterior separation greater than 35 cm which are incompatible with MR for Calculating ATtenuation (MRCAT) reconstruction

10. Contra-indications to receiving gadolinium contrast

11. KPS < 80

12. Pelvic or Prostate MRI or CT (MRI preferred) evidence of radiographic T3, T4, or N1 disease

13. Prior history of transurethral resection of the prostate

14. Prior history of urethral stricture

15. Prior history of pelvic irradiation

16. History of inflammatory bowel disease

17. Unable to give informed consent

18. Unable to complete quality of life questionnaires

19. Abnormal complete blood count, including any of the following:

    • Platelet count less than 75,000/ml
    • Hb level less than 10 gm/dl
    • White blood cell (WBC) less than 3.5/ml
    • Abnormal renal function tests (creatinine > 1.5)

Trial design

Primary purpose: Treatment

Allocation: N/A

Interventional model: Single Group Assignment

Masking: None (Open label)

---

91 participants in 1 patient group

MRI-guided Intensity Modulated Radiotherapy

Experimental group

Description:

All patients will undergo the injection of a hydrogel rectal spacer (SpaceOAR) 1 week before simulation. Patients will undergo ultra-hypofractionated radiation utilizing MR-guided, daily online adaptive planning. Patients will receive 9 Gy/fraction for five fractions for a total dose of 45 Gy to the prostate DIL while the rest of the prostate will be treated to a minimum dose to the rest of the prostate of 30 Gy in five fractions. Radiation will be given every other day, Monday through Friday, until 5 treatments have been completed. Patients will be followed at three and six months after treatment, and every six months thereafter through month 24 (+/- 4 weeks).

Treatment:

Device: Hydrogel rectal spacer (SpaceOAR)

Radiation: 1.5 T Elekta Unity MR-Linac system