Benign Conditions

Benign Prostatic Hyperplasia

Bladder Cancer

Female Urology

Genitourinary Cancers

Genomic Testing

Hormone Therapy

Kidney Cancer

Challenging Anatomy

Innovative Techniques

Laser Lithotripsy

PCNL Tech & Devices

Ureteroscopy Tech & Devices

Kidney Stones

Men's Health

Next-Generation Imaging

Voiding Dysfunction

OAB and Incontinence

Pediatrics

Controveries in Urologic Cancer

Drug Therapy

Prostate Cancer

Sexual Dysfunction

UTUC

Cosmetic Surgery

Urologic Surgery

Business

Practice Management

Malpractice Consult

Health Law & Policy

Media

Case-Based Peer Perspectives

Investigator Perspectives 

Medical World News

Podcasts

Urology Medical Perspectives

UTv Videos

Peer Exchange

News Network

Virtual Tumor Board

Insights

Medcast

Peers & Perspectives

Conferences

Conference Listing

Conference Previews 

Conference Recaps

Publications

Urology Times Journal

Editorial Advisory Board

Urologists in Cancer Care

Supplements and Featured Publications

CME/CE

Resources

Begin Your Journey: Tackling Burnout

Live Events

Interactive Tools

Job Board

Partners

Subscribe

Urology Times is the leading resource for urologists & allied health professionals offering clinical analysis, policy perspectives, & practical advice.

About Us

Advertise

Editorial

Contact Us

Terms and Conditions

Privacy

Do not sell my Personnal Information

Urology Times | News & Insights for Urologists & Health Professionals

Facebook

LinkedIn

Spotlight

Peers and Perspectives

Clinical

1rem

Authors

This article presents an overview of the pathophysiology of varicoceles and discusses indications for treatment, two primary repair techniques, and treatment outcomes.

Varicocele: Treatment indications and repair techniques

The FDA has accepted a Biologics License Application (BLA) seeking approval of nivolumab (Opdivo) co-formulated with Halozyme’s proprietary recombinant human hyaluronidase (rHuPH20), or subcutaneous nivolumab, for the treatment of patients with all previously approved solid tumor indications for nivolumab as a monotherapy, monotherapy maintenance following completion of combination therapy with nivolumab plus ipilimumab (Yervoy), or in combination with chemotherapy or cabozantinib (Cabometyx).

Nivolumab is currently approved under several indications, including in combination with ipilimumab for the first-line treatment of patients with intermediate- or poor-risk advanced renal cell carcinoma (RCC), in combination with cabozantinib for the first-line treatment of patients with advanced RCC, for the treatment of patients with advanced RCC who have received prior anti-angiogenic therapy, and in combination with cisplatin and gemcitabine for the first-line treatment of patients with unresectable or metastatic urothelial carcinoma.

The FDA is set to have a decision regarding the subcutaneous nivolumab formulation on or by December 29, 2024.

 According to a news release from Bristol Myers Squibb,

 approval of the formulation would make it the first and only subcutaneously administered PD-1 inhibitor.

“We believe subcutaneous nivolumab has the potential to make a significant difference in the lives of patients, which is reinforced by the FDA’s acceptance of our application,” said Gina Fusaro, PhD, vice president, global program lead, Bristol Myers Squibb, in the news release.

 “Opdivo is a foundational PD-1 inhibitor approved for many different types of cancer, and our continued investment in research that puts patients first remains a priority. If approved by the FDA, the subcutaneous administration of nivolumab would provide patients and their physicians with a new option that delivers the same well-known benefits as IV Opdivo but with the improved convenience of an injection administered in 3 to 5 minutes rather than a 30-to-60-minute infusion.”

The BLA submission is supported by findings from the phase 3 CheckMate-67T trial (NCT04810078), in which subcutaneous nivolumab met the study’s co-primary end points by demonstrating noninferiority to intravenous (IV) nivolumab regarding time average nivolumab serum concentration over 28 days (C

; geometric mean ratio [GMR}, 2.098; 90% CI, 2.001-2.200) and minimum serum concentration at a steady state (C

Data from the study, which were presented at the 2024 American Society of Clinical Oncology Genitourinary Cancers Symposium in San Francisco, California,

 also showed that subcutaneous nivolumab demonstrated noninferiority to IV nivolumab in the key powered secondary end point of objective response rate (ORR). Specifically, the subcutaneous arm demonstrated an ORR of 24.2% (95% CI, 19.0-30.0) per blinded independent central review (BICR), compared with 18.2% (95% CI, 13.6-23.6) in the IV arm.

The safety profile for subcutaneous nivolumab was consistent with that of the IV formulation. Among patients who received the subcutaneous formulation, 8.1% experienced injection-site reactions, with all being low-grade and transient. Deaths due to study drug toxicity occurred in 3 patients in the subcutaneous arm and 1 patient in the IV arm. Most deaths that occurred during the study were due to disease progression.

In total, the phase 3, open-label CheckMate-67T trial enrolled 495 patients with advanced or metastatic ccRCC who had received prior systemic therapy. Patients were randomly assigned 1:1 to receive 1200 mg subcutaneous nivolumab plus rHuPH20 every 4 weeks (n = 248) or to 3 mg/kg IV nivolumab every 2 weeks (n = 247) for up to 2 years of treatment or until disease progression, unacceptable toxicity, withdrawal, or death.

The co-primary pharmacokinetic end points for noninferiority testing were C

 of subcutaneous nivolumab vs IV nivolumab. The key secondary end point was ORR per BICR.

Final completion of the CheckMate-67T study is expected in January 2026.

1. U.S. Food and Drug Administration accepts Bristol Myers Squibb’s application for subcutaneous nivolumab (nivolumab and hyaluronidase). News release. Bristol Myers Squibb. May 6, 2024. Accessed May 7, 2024. https://news.bms.com/news/corporate-financial/2024/U.S.-Food-and-Drug-Administration-Accepts-Bristol-Myers-Squibbs-Application-for-Subcutaneous-Nivolumab-nivolumab-and-hyaluronidase/default.aspx

2. Bristol Myers Squibb announces updated action date by the U.S. Food and Drug Administration for subcutaneous nivolumab (nivolumab and hyaluronidase). News release. Published online and accessed May 21, 2024. https://investors.bms.com/iframes/press-releases/press-release-details/2024/Bristol-Myers-Squibb-Announces-Updated-Action-Date-by-the-U.S.-Food-and-Drug-Administration-for-Subcutaneous-Nivolumab-nivolumab-and-hyaluronidase/default.aspx

3. George S, Bourlon TB, Chacon MR, et al. Subcutaneous nivolumab (NIVO SC) vs intravenous nivolumab (NIVO IV) in patients with previously treated advanced or metastatic clear cell renal cell carcinoma (ccRCC): Pharmacokinetics (PK), efficacy, and safety results from CheckMate 67T. 

4. A study of subcutaneous nivolumab versus intravenous nivolumab in participants with previously treated clear cell renal cell carcinoma that is advanced or has spread (CheckMate-67T). ClinicalTrials.gov. Last updated March 1, 2024. Accessed May 7, 2024. https://clinicaltrials.gov/study/NCT04810078

The FDA is set to have a decision regarding the subcutaneous nivolumab formulation on or by December 29, 2024. 

News

FDA accepts BLA for subcutaneous nivolumab in solid tumors

We have a question about coding and reporting the UroCuff procedure. Some recommend reporting it with 

) code 51728 with modifier –52 (reduced services), whereas others recommend using 

 code 55899 (Unlisted procedure, male genital system). What are your thoughts on this conundrum?  

The UroCuff test is a noninvasive (no indwelling catheter) natural fill bladder pressure test. Currently, there is no 

 nor Healthcare Common Procedure Coding System code that specifically describes the UroCuff test. This lack of a specific code to report this service can be a burden to both the payer and the provider. Therefore, if this test is considered medically necessary and as such covered by a payer, the path to correct and efficient adjudication may be different for each payer.

Following is a discussion of each option.

Code 51728 (Complex cystometrogram [ie, calibrated electronic equipment]; with voiding pressure studies [ie, bladder voiding profile], any technique)includes both the complex cystometrogram (CMG) and a voiding pressure study. The UroCuff procedure measures bladder voiding pressure but does not provide measurements for the complex CMG. Modifier –52 is defined in 

 as follows: “Reduced Services: Under certain circumstances a service or procedure is partially reduced or eliminated at the physician's discretion. Under these circumstances the service provided can be identified by its usual procedure number and the addition of modifier –52, signifying that the service is reduced. This provides a means of reporting reduced services without disturbing the identification of the basic service.”

Based on the modifier definition, appending the modifier –52 to the 51728 would signify to the payer that a portion of the procedure has been eliminated at the discretion of the physician. Specifically, the physician has elected to perform a voiding pressure study, any technique without a concomitant CMG.

This method of reporting may be preferred by some payers, as it allows for processing of those claims under existing contract and coverage terms and appears to conform with the intended use of the modifier and 

. In their Coding and Advocacy Brief posted on 05-03-2017, the American Urological Association (AUA) examined the UroCuff and issued the following statement: “The Committee determined that 51728-52 is not appropriate to report the voiding pressure study. At this time, the Committee is unaware of a 

 code available to report using a penile pressure cuff for a urethral pressure study. If there are questions, please contact your insurer for possible alternative 

 code or set of codes is agreed upon, we recommend that the agreement is put in writing.”1 (note: link no longer active)

The opinion of the AUA, a premier urologic association, is given significant weight by payers when considering the best way to adjudicate claims. Therefore, payers may require reporting of UroCuff under code 53899 (Unlisted procedure, urinary system) or code 55899 (Unlisted procedure, male genital system).

Medicare and other payers will likely require medical record review regardless of whether you choose to report the voiding pressure study with an unlisted code (53899/55899) or 51728-52, until a coverage policy has been adopted by the payer. Multiple Medicare carriers have issued local coverage articles (LCAs) for some states that direct the use of 55899 with specific verbiage in Box 19 for reporting the UroCuff test. One carrier also included a reimbursement rate in the LCA.

It should be noted as well that regardless of the choice of code 51728-52 or 53899 or 55899, reporting the service will require that Box 19 in the claim form be populated. In these cases, it is recommended that an office use consistent verbiage in Box 19. A payer may use the combination of codes and Box 19 verbiage to develop an adjudication pathway, pricing, and coverage that does not require manual processing and record review for every case.

Given the above background, when determining which code you should use, you must consider your Medicare carrier’s published rules and commercial payer processing policies. Successful urology practices will often establish an internal reporting for UroCuff and assign the revenue cycle management charge release team or, through a series of programmed rules, payer-specific billing protocols. It is imperative to frequently check with the payer regarding reporting and coverage for the UroCuff test as recommended for any other service rendered. Obtain the directions for reporting the UroCuff test in writing, where possible.

Send coding and reimbursement questions to Jonathan Rubenstein, MD, and Mark Painter c/o

Questions of general interest will be chosen for publication. The information in this column is designed to be authoritative, and every effort has been made to ensure its accuracy at the time it was written. However, readers are encouraged to check with their individual carrier or private payers for updates and to confirm that this information conforms to their specific rules.

"When determining which code you should use, you must consider your Medicare carrier’s published rules and commercial payer processing policies," write Jonathan Rubenstein, MD, and Mark Painter. 

UroCuff coding presents a “conundrum” for billers

Investigators have found that the time to testosterone recovery following androgen deprivation therapy (ADT) with gonadotropin-releasing hormone (GnRH) agonists varies for patients with prostate cancer depending on the length of treatment, baseline testosterone levels, and age.

Findings from the pooled analysis were published in 

“Our findings give patients and doctors valuable insights into what to expect after ADT treatment, helping them make informed decisions about managing side effects and improving long-term outcomes," said senior author Amar U. Kishan, MD, in a news release on the findings.

 Kishan is the executive vice chair of radiation oncology at the David Geffen School of Medicine at the University of California, Los Angeles.

Overall, the study analyzed data from 1444 men who were enrolled across 5 clinical trials in the Meta-Analysis of Randomized Trials in Cancer of the Prostate (MARCAP) Consortium. Among all patients included in the analysis, ADT duration was 4 months for 115 patients, 6 months for 880 patients, 18 months for 353 patients, 28 months for 36 patients, and 36 months for 60 patients. The median survival time was 14.8 years (IQR, 9.3-18), and the median follow-up for survivors was 11 years (IQR, 10-12).

Data showed that the time to noncastrate testosterone recovery and nonhypogonadal testosterone recovery varied by ADT duration. Specifically, the median time to noncastrate testosterone recovery was 8.3 months for those who received 4-month ADT, 5.9 months for 6-month ADT, 5.8 months for 18-month ADT, 14.1 months for 28-month ADT, and 11.7 months for 36-month ADT. The median time to nonhypogonadal testosterone recovery was 20.3 months for those who received 4-month ADT, 8.1 months for 6-month ADT, 11.8 months for 18-month ADT, 27 months for 28-month ADT, and 44.3 months for 36-month ADT.

Further, higher baseline testosterone level and lower age were associated with an increased likelihood for testosterone recovery to noncastrate and nonhypogonadal levels (

 < .001 for both). Age specifically was shown to have large impacts on testosterone recovery.

The unadjusted median effective castration period was 12.8 months, 11.9 months, 23.8 months, 42.2 months, and 47.9 months for those who received ADT for 4 months, 6 months, 18 months, 28 months, and 36 months, respectively. Cox analysis revealed no linear associations between effective castration period and oncological outcomes for any ADT duration.

However, adjusted natural cubic spline analysis did demonstrate a non-linear association between effective castration period and metastasis-free survival (MFS) for patients receiving 6 and 18 months of ADT. According to cubic spline analysis, the optimal effective castration period to achieve MFS benefit was 10.6 months (95% CI 6.0–16.4) for patients receiving 6 months of ADT and 18 months (95% CI 18.0–25.8) for patients receiving 18 months of ADT.

Overall, the authors concluded, “An understanding of [testosterone recovery] kinetics is critical for counseling of men who are starting ADT so that they have realistic expectations regarding the likely time to resolution of ADT-related side effects. Traditional multivariable Cox analyses did not reveal any association between effective castration period and oncological outcomes across the ADT treatment periods. However, there was a nonlinear association between effective castration period and MFS whereby a longer effective castration period was associated with better oncological outcomes. This finding is hypothesis-generating, and future trials should confirm whether a longer ADT duration is needed with GnRH antagonists (which allow more rapid [testosterone recovery]) than with GnRH agonists.”

1. Ong WL, Romero T, Roy S, et al. Testosterone recovery following androgen suppression and prostate radiotherapy (TRANSPORT): A pooled analysis of five randomized trials from the meta-analysis of randomized trials in cancer of the prostate (MARCAP) consortium. 

. 2024:S0302-2838(24)02601-0. doi:10.1016/j.eururo.2024.09.009

2. Study helps predict how long it will take for testosterone to return to normal after prostate cancer treatment. News release. UCLA Health. September 25, 2024. Accessed September 26, 2024. https://www.uclahealth.org/news/release/study-helps-predict-how-long-it-will-take-testosterone

“Our findings give patients and doctors valuable insights into what to expect after ADT treatment, helping them make informed decisions about managing side effects and improving long-term outcomes," says Amar U. Kishan, MD. 

Testosterone recovery following ADT varies across patients, study shows

Maintenance pembrolizumab (Keytruda) following stereotactic ablative radiotherapy (SABR) boost to bladder tumor and concurrent radio-chemotherapy was found to be both effective and well tolerated in patients with muscle-invasive bladder cancer, according to data presented at the 2024 American Society for Radiation Oncology Annual Meeting in Washington, DC.

“There has been an increasing trend of utilizing organ-preserving therapies in the management of bladder cancer over the past decades. TMT [tri-modal therapy], including [transurethral resection of bladder tumor], chemotherapy, and radiotherapy, is an established multi-disciplinary approach for bladder preservation with outcomes that are comparable to those of radical cystectomy. However, [previous research] has shown the 5-year local recurrence in the bladder is close to 40%, and 5-year distant metastasis was more than 30%.

 Our pilot study showed that the strategy for SABR boost as part of TMT was well tolerated and effective in [patients with] MIBC. So we conducted this study to evaluate the effectiveness of pembrolizumab as maintenance therapy following TMT in [patients with] bladder cancer,” said study author Shang-bin Qin, MD, of Peking University First Hospital, Beijing, China.

The primary end point for the study was PFS. Secondary end points included overall survival (OS), bladder-intact event-free survival, and safety signals.

The study was single arm and single site. Patients received pembrolizumab for 1 year in up to 17 cycles. Patients were eligible if they had cT2-4N0M0 MIBC, declined or were ineligible for radical cystectomy, had an ECOG Performance Status of 0 or 1, had primary bladder cancer with urothelial carcinoma > 50%, and achieved complete response (defined as tumor free on bladder MRI and cystoscopy) after receiving maximal TURBT then SABR.

“Patients received SABR to the tumor or tumor bed in the bladder followed by conventionally fractionated RT to pelvis and total bladder with concomitant weekly low-dose gemcitabine chemotherapy,” wrote the authors. Following TMT, patients who achieved a CR went on to receive maintenance pembrolizumab.

A total of 46 patients were enrolled in the study. Median age was 69 years (range, 34-86 years). In addition, 78% of the patient population was male. In terms of clinical staging, 39 (85%) patients had T2 disease and 7 (15%) patients had T3 disease. Eighteen (39%) patients had complete TURBT vs 28 (61%) patients who had incomplete TURBT. Forty-four (96%) patients received concurrent chemotherapy, and 9 (20%) patients received neoadjuvant chemotherapy.

Median follow-up was 10 months. Ten patients completed 17 cycles of pembrolizumab.

“The estimated PFS, local control, and OS were 85%, 93%, and 97%, respectively,” Qin reported.

Any-grade treatment-related adverse events (TRAEs) were reported in 11 (24%) patients. Grade 3 TRAEs occurred in 3 (7%) patients and consisted of myocarditis, cystitis, and pneumonitis. Seventeen patients discontinued treatment with pembrolizumab.

“Pembrolizumab maintenance therapy after SABR boost to bladder tumor and concurrent radio-chemotherapy was well tolerated with promising efficacy in the early analysis. Immune-related toxicity was consistent with prior monotherapy trials. Correlative analyses from blood and tissue specimens will be presented in the future,” Qin concluded.

1. Qin SB, Yu W, He ZS, et al. Pembrolizumab monotherapy following tri-modality treatment for selected patients with muscle-invasive bladder cancer. Presented at: 2024 American Society for Radiation Oncology Annual Meeting. September 29-October 2, 2024. Washington, DC. Abstract 220. 

https://astro2024.eventscribe.net/agenda.asp?startdate=9/30/2024&enddate=9/30/2024&BCFO=M&pfp=Browse%20by%20Day&fa=&fb=&fc=&fd=

2. Giacalone NJ, Shipley WU, Clayman RH, et al. Long-term outcomes after bladder-preserving tri-modality therapy for patients with muscle-invasive bladder cancer: an updated analysis of the Massachusetts General Hospital experience. 

2017;71(6):952-960. doi:10.1016/j.eururo.2016.12.020

“Pembrolizumab maintenance therapy after SABR boost to bladder tumor and concurrent radio-chemotherapy was well tolerated with promising efficacy in the early analysis," said Shang-bin Qin, MD.   

Pembrolizumab after TMT shows promise in muscle-invasive bladder cancer

Escalated-dose hypofractionated radiation therapy may provide better efficacy versus conventionally fractionated radiation for longer than a decade in patients with localized prostate cancer, according to a longterm analysis of a previously published phase 3 trial.

American Society for Radiation Oncology (ASTRO) 2024 Annual Meeting

 in Washington, DC, this weekend showed an escalated dose of hypofractionated radiation was associated with a 47% improved 10-year failure rate compared to fractionated radiation therapy in men with localized prostate cancer. The findings also showed no significant differences in longterm toxicity between the treatment options, as well as similar overall survival rates.

Led by CJ Hassanzadeh, MD, MPH, assistant professor of radiation oncology at The University of Texas MD Anderson Cancer Center and clinical director of the Bone Metastasis Clinic, investigators aimed to build on prior prospective phase 3 study findings showing “superior (prostate) cancer control” with hypofractionated radiation. Their longterm outcome analysis sought to determine whether the initial superiority was maintained between the two.

Indeed, prior research comparing hypofractionated versus conventional radiation therapy has shown at least a consistent tolerability or safety profile between the dosage options in patients with genitourinary cancers, complementary to the efficacy findings in initial research into prostate cancer.

In this analysis, Hassanzadeh and colleagues randomized men with localized prostate cancer to either conventional fractionated or hypofractionated radiation therapy between 2001 – 2010. The conventional dose entailed 75.6Gy delivered in 1.8-Gy fractions over 8.4 weeks; the hypofractionated dose was 72Gy delivered in 2.4-Gy fractions over 6 weeks. All patients’ radiotherapy doses were modulated for intensity.

The patient arms were stratified at treatment randomization based on receipt of androgen deprivation therapy (ADT) and prostate-specific antigen (PSA) levels ≤10 ng/mL to ensure balanced patient characteristics. The team used modified Radiation Therapy Oncology Group (RTOG) criteria to grade late gastrointestinal and genitourinary toxicity.

Investigators sought a primary outcome of failure per PSA nadir plus 2 ng/mL, or initiation of salvage therapy. They calculated time to failure by start of radiation; time to toxicity was measured from the end of radiation.

The team enrolled 206 patients with localized prostate cancer; a majority had intermediate National Comprehensive Cancer Network (NCCN) grades (71%) and PSA ≤10 ng/mL (90% at baseline. Approximately half (48%) had Gleason grade group 2 cancer. Participants were split 1:1 to either conventional (n = 102) or hypofractionated (n = 104) radiation regimens.

Patients were followed up for a median of 11 years; one-fourth (24%) were administered ADT in that time.

Only 13 patients receiving hypofractionated radiation therapy experienced treatment failure, versus 22 patients receiving a conventional regimen—however, the outcome was not statistically significant (

 = .077). Patients receiving hypofractionated regimen reported an 11% failure rate over 10 years (95% CI, 5.5 – 18.1), versus 21% among the conventional regimen (95% CI, 13.0 – 30.5).

Investigators observed a significantly improved 10-year failure rate among the subgroup of men receiving hypofractionated radiation therapy who did not receive ADT (13%), versus the subgroup of men receiving conventional radiation therapy who did not receive ADT (26%; 

That said, median overall survival over 20 years was similar across the 2 treatment arms (

 = .076), as well as the 15-year distant metastasis rate (8% vs 4%; 

Regarding safety, Hassanzadeh and colleagues noted similar 10-year, cumulative grade ≥2 genitourinary toxicity between the hypofractionated arm (26%) and conventional arm (23%; 

 = .54), as well as rates of grade ≥2 gastrointestinal toxicity (13% vs 5%, respectively; 

 = .08). The team reported no grade 4 toxicities among the treated patients.

“Long-term outcomes suggest a benefit in terms of treatment failure to dose-escalated, hypofractionated radiation, especially among patients not receiving ADT, without worse late toxicity,” the investigators concluded.

Hassanzadeh, CJ, Kuban DA, Pasya S, Bassett R, et al. Hypofractionated, Dose-Escalated Radiation vs. Conventionally Fractionated Radiation for Localized Prostate Cancer: Long-Term Update of a Phase 3, Prospective, Randomized Controlled Trial. Poster presented at: American Society for Radiation Oncology (ASTRO) 2024 Annual Meeting. Washington, DC. September 29 – October 2, 2024.

Saylor B. Hypofractionated prostate RT does not increase toxicity vs conventional RT. 

. Published October 29, 2021. Accessed September 27, 2024. https://www.urologytimes.com/view/hypofractionated-prostate-rt-does-not-increase-toxicity-vs-conventional-rt

Follow-up phase 3 analyses support a hypofractionated radiation therapy regimen to conventional dosing in patients with prostate cancer. 

Hypofractionated radiation therapy improves 10-year prostate cancer outcomes

Gallium-68 (Ga-68) prostate-specific membrane antigen (PSMA)-11 radiotracer may feasibly guide positron emission tomography (PET)-based proprietary radiation therapy SCINTIX in the treatment of bony metastases in patients with 

 in Washington, DC, this weekend show the Ga-68 PSMA-11 tracer can help guide SCINTIX therapy to treat metastasized prostate cancer—despite the software of the novel radiation procedure being originally developed to work with F-18 tracers. The California-based investigation team, supported by RefleXion Medical, believe the data reasonably support the use of Ga-68 PSA-11 radiotracer in PET-guided SCINTIX treatments conducted through the X1 machine.

The X1 system is a biology-guided radiotherapy machine designed to deliver targeted radiation based on real-time PET feedback of tumor positioning in patients with cancer; according to the company, it is delivered in ≤5 fractionated doses and touts capability to reduce the risk of radiation-based adverse events. Investigators led by Chunhui Han, PhD, of the City of Hope National Medical Center, sought to evaluate Ga-68 PSMA-11 tracer’s feasibility to guide SCINTIX treatment through the X1 machine for patients with bone-metastasized prostate cancer.

The team conducted a retrospective analysis of patients who underwent diagnostic scans at their institution via Ga-68 PSMA-11 PET or computed tomography scans. Their review ultimately included 5 patients with PET-avid bone metastases.

Investigators then drew gross tumor volumes (GTVs) for a PET-avid bone lesion per patient. Planning target volumes (PTVs) were defined by adding 5 mm margins to GTVs, while biology tracking zone (BTZ) was created to define the potentially full range tumor motion plus margin.

“To create SCINTIX treatment plans on the X1 machine, the diagnostic PET images were first converted to simulated treatment planning PET images on the X1 machine to account for differences in PET detector size and reconstruction algorithms,” investigators explained. “Then the activity concentration (AC) and normalized target signal (NTS) were calculated.”

Mean Ga-68 injection dose was 4.86 mCi (range, 4.1 – 5.6) per patient prior to PET or CT scans. Average maximum PET activity in the GTVs was 25.2 kBg/ml (range, 13.3 – 43.5), and mean PET activity was 16.44 kBg/ml (range, 14.3 – 24.2). Targets in the simulated treatment planning PET images had a mean AC value of 11.5 kBg/ml (range, 6.2 – 18.9), and a mean NTS value of 12.6 kBg/ml (range, 8.7 – 22.2).

Average treatment beam-on time was 1678 seconds (range, 1416 – 2120), and mean PTV volume was 15.7 cc (range, 7.0 – 30.9). Mean PTV coverage was 93.6%; conformity index was 1.14; and homogeneity index was 1.63.

Han and colleagues expressed high interest in the findings, which they note may be among the first studies to observe the feasibility of Ga-68 based tracers for planning SCINTIX treatment instead of F-18 radiotracers.

“Metastatic bony lesions from prostate cancer could have sufficient positron emission strength for SCINTIX treatment when Ga-68 PSMA-11 radiotracer is used at diagnostic dose levels,” they concluded. “This study demonstrated the feasibility of using Ga-68 PSA-11 radiotracer for future PET-guided SCINTIX treatments on the X1 machine.”

Han C, Wong JYC, Williams TM, Liu A. Feasibility of Biology-Guided Radiotherapy with Gallium-68 PSMA-11 Radiotracer for Bony Metastases in Prostate Cancer Patients. Poster presented at: American Society for Radiation Oncology (ASTRO) 2024 Annual Meeting. Washington, DC. September 29 – October 2, 2024.

SCINTIX Therapy. Accessed September 28, 2024. https://scintixtherapy.com.

Ga-68 PSMA-11 radiotracer may be a feasible option for SCINTIX radiation therapy in patients whose prostate cancer has spread to the bones. 

Thomas A. Masterson, MD

Articles

Latest Updated Articles