Clinical trial NCT05597852: Using Rectal Hydrogel Spacer for Salvage SABR in Prostate Cancer
Official title: Feasibility of Integrating Rectal Hydrogel Spacer for Salvage Treatment Using Stereotactic Ablative Body Radiotherapy for Locally Recurrent Prostate Cancer
Study type: INTERVENTIONAL
Overall status: RECRUITING
Phase: NA
Conditions: Prostate Cancer
Lead sponsor: Sunnybrook Health Sciences Centre
Sponsor class: OTHER
First posted: 2022-10-28
Enrollment: 10
Sex: MALE
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: NA
Intervention model: SINGLE_GROUP
Intervention model description: Patients with local recurrence of prostate cancer with previous irradiation will have a hydrogel spacer, SpaceOAR™ inserted.
Primary purpose: DEVICE_FEASIBILITY

Brief summary: There are several single institutional series that have reported their experience with salvage radiotherapy options that include EBRT, LDR and HDR brachytherapy. Gastrointestinal (GI) toxicity with salvage radiotherapy range between14-58%, respectively for patients undergoing re-irradiation. There is a concern for an increased risk of fistula development in these patients who receive second course of radiation. Hypofractionation using SABR has been utilized in the re-irradiation setting for prostate cancer with good tumor control and toxicity outcomes. In order to decrease the rectal toxicity, dose to the rectum should be kept as low as possible. Several techniques can be used to achieve this: tighter dosimetric dose painting, better patient or organ immobilization or use of a biodegradable gel. The Investigators ropose a phase I study to assess placement of a hydrogel spacer between the prostate and rectum, in an effort to decrease toxicity and improve patient's bowel quality of life.

Detailed description: Primary treatment of prostate cancer includes surgery or radiotherapy. Although significant improvements have been made in patient selection and treatment planning, local recurrence remains a common problem.

In the case of local recurrence after radiation, salvage options may include prostatectomy, salvage external beam radiotherapy (EBRT) or brachytherapy with low-dose (LDR) or high-dose rate (HDR) implantation, cryotherapy and high intensity focused ultrasound.

There are several single institutional series that have reported their experience with salvage radiotherapy options that include EBRT, LDR and HDR brachytherapy (2-7). Rates of grade 2 or higher genitourinary (GU) and gastrointestinal (GI) toxicity with salvage radiotherapy range between 36-50% and 14-58%, respectively for patients undergoing re-irradiation. GI Toxicity, however, is dependent on total rectal dose. This is especially important among patients who are being considered for re-irradiation. There is a concern for an increased risk of fistula development in these patients who receive second course of radiation although with salvage brachytherapy that risk was only 2% and seen only in patients who had a surgical intervention after salvage brachytherapy.

Hypofractionated regimens have become increasingly common in treatment of prostate cancer, especially with advancement of immobilization and imaging techniques that allow smaller margins and daily verification. Hypofractionation using SABR (Stereotatic Ablative Body Therapy) has been utilized in the re-irradiation setting for prostate cancer with good tumor control and toxicity outcomes. In order to decrease the rectal toxicity, dose to the rectum should be kept as low as possible. Several techniques can be used to achieve this: tighter dosimetric objectives, dose painting, better patient or organ immobilization or use of a biodegradable gel. The latter has been used to increase the distance between the prostate and the rectum for patients who are undergoing prostate radiotherapy. Placement of a hydrogel spacer between the prostate and the rectum has been proven in a randomized controlled trial to reduce rectal dose resulting in decreased acute and long-term rectal toxicity and improvement in bowel-related quality of life. SpaceOAR is an FDA and Health Canada approved, commercially available rectal spacer that, when placed between the prostate and the rectum, has demonstrated to greatly reduce rectal dose and toxicity for patients undergoing external beam radiation and LDR brachytherapy.

Eligibility criteria: Inclusion Criteria:

* Histologically and radiologically confirmed locally recurrent prostate adenocarcinoma
* Willing to give informed consent to participate in this clinical trial
* Able and willing to complete EPIC and EQ-5D questionnaires

Exclusion Criteria:

* Contraindication to prostate MRI
* Anticoagulation medication (if unsafe to discontinue)
* Diagnosis of bleeding diathesis
* Poor baseline urinary function defined as International Prostate Symptom Score (IPSS) \>20
* Evidence of castrate resistance (defined as PSA \> 3 ng/ml while testosterone is \< 0.7nmol/l). Patients could have been on combined androgen blockade but are excluded if this was started due to PSA progression.
* Definitive extrapelvic nodal or distant metastatic disease on staging investigations.
* Prior ultra-hypofractionated radiotherapy ( SBRT of 5Gy/fraction or higher)

Primary outcomes:
measure: Feasibility of SpaceOAR
timeFrame: 5 year
Secondary outcomes:
measure: Acute and late cumulative incidence of toxicities
timeFrame: 5 years
measure: Quality of Life using EPIC
timeFrame: 5 years
measure: Biochemical disease-free survival
timeFrame: 5 years
measure: Use of salvage ADT
timeFrame: 18 Months
measure: Health utilities
timeFrame: 5 years
measure: Quality of Life using IPSS
timeFrame: 5 years
Other outcomes:
Locations:
city: Toronto
country: Canada
facility: Sunnybrook Odette Cancer Centre
state: Ontario
Study officials:
affiliation: Sunnybrook
name: Amandeep Taggar, MD
role: PRINCIPAL_INVESTIGATOR
References: