Proton Therapy Spot Placement for Prostate Cancer

Overseen By Catherine Duke-Taylor, BS

Age: 18+

Sex: Male

Trial Phase: Academic

Sponsor: Thompson Cancer Survival Center

Disqualifiers: Prior pelvic radiotherapy, diverticulitis, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Compensation: Varies

Number of Visits: Unknown

Duration: 6-8 weeks

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial explores a new method called "Spot Delete" in proton therapy for treating prostate cancer. The goal is to improve the aiming of proton beams, reducing side effects like diarrhea and rectal bleeding by avoiding certain areas in the body. Researchers will test two planning methods: the new "Spot Delete" technique and the standard approach. Men diagnosed with prostate cancer at stages T1-T2c, who have not undergone certain prior treatments, may be eligible to participate. As an unphased trial, this study offers patients the chance to contribute to innovative research that could enhance future prostate cancer treatments.

Do I have to stop taking my current medications for the trial?

The trial protocol does not specify whether you need to stop taking your current medications. However, since prior systemic therapy for prostate cancer is an exclusion criterion, you may need to discuss your current medications with the trial team.

Will I have to stop taking my current medications?

The trial information does not specify whether you need to stop taking your current medications. It's best to discuss this with the clinical trial team to get a clear answer.

What prior data suggests that this technique is safe for prostate cancer treatment?

Research has shown that the "Spot Delete" technique for proton therapy is promising in terms of safety. Studies have found that this method can lower the radiation dose to sensitive areas like the rectum and bladder, potentially leading to fewer side effects for patients. Early results indicate that patients experienced a better quality of life after treatment with this technique compared to traditional methods.

Proton therapy targets cancer more precisely than standard X-ray radiation. This precision helps protect healthy tissues, reducing unwanted side effects. The "Spot Delete" technique enhances these benefits by better controlling the proton beam's path, potentially making it even safer for prostate cancer treatment. ^{1 2 3 4 5}

Why are researchers excited about this trial?

Researchers are excited about the "Spot Delete" technique for proton therapy in prostate cancer because it offers a more precise approach to treatment planning. While traditional proton therapy can inadvertently target the rectum, sigmoid, and small bowel, "Spot Delete" aims to avoid these areas by controlling where proton spots are placed. This could potentially reduce side effects related to the rectum and bladder, making the treatment safer and more comfortable for patients. The technique also uses a specialized computer model to better understand the relationship between proton beam energy and these side effects, paving the way for more targeted and personalized cancer treatments.

What evidence suggests that the "Spot Delete" technique is effective for prostate cancer?

Research has shown that the "Spot Delete" technique in proton therapy, which participants in this trial may receive, helps reduce unwanted radiation in sensitive areas like the rectum and bowel. Studies have found that this method lowers the radiation dose to these areas and speeds up treatment delivery. This is important because it might reduce side effects such as diarrhea and rectal bleeding. Proton therapy, also studied in this trial using a traditional planning system, is already known for targeting cancer cells more precisely while protecting healthy tissue better than traditional X-rays. This makes it a promising option for treating prostate cancer while minimizing harm to other parts of the body. ^{1 2 3 5 6}

Who Is on the Research Team?

Samantha Hedrick, PhD

Principal Investigator

Thompson Proton Center

Are You a Good Fit for This Trial?

Men over 18 with low to intermediate risk prostate cancer, not previously treated with pelvic radiotherapy, cryotherapy, hyperthermia or chemotherapy. They must have a clinical stage T1-T2c prostate cancer, PSA < 20 ng/mL, Gleason Score ≤ 7 and be in good physical condition (ECOG status 0-1). Participants should also be willing to complete quality of life surveys.

Inclusion Criteria

My prostate cancer has a Gleason score of 7 or less.

I am fully active or can carry out light work.

My breast cancer is in an early stage (T1-T2c).

Exclusion Criteria

I have had radiation therapy to my pelvic area before.

I have had cryotherapy or hyperthermia for prostate cancer.

I have received chemotherapy for prostate cancer.

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Treatment

Participants receive proton therapy with or without the 'Spot Delete' technique to control proton spot placement

6-8 weeks

Weekly visits for treatment

Follow-up

Participants are monitored for safety and effectiveness after treatment

10 years

Annual visits

What Are the Treatments Tested in This Trial?

Interventions

• Spot Delete planning for proton therapy
• Traditional proton treatment planning system

Trial Overview The trial is testing 'Spot Delete' planning for proton therapy against traditional methods. It aims to reduce side effects by avoiding proton spots in sensitive areas like the rectum and bowel during treatment for prostate cancer.

How Is the Trial Designed?

Group I: "Spot Delete" Experimental Treatment 1 Intervention

A unique technique called "Spot Delete" will be utilized to control the placement of spots during treatment planning, to prohibit proton spots from being placed in the rectum, sigmoid, and small bowel. A specialized computer model will be used to study how the energy of the proton beam (linear energy transfer) is related to rectal and bladder side effects.

Group II: Control Arm Active Control 1 Intervention

The proton spots that are placed by the treatment planning system are not modified

Spot Delete planning for proton therapy is already approved in United States, European Union for the following indications:

Approved in United States as Proton Therapy for:

• Prostate cancer
• Brain tumors
• Breast cancer
• Cancer in children
• Eye melanoma
• Esophageal cancer
• Head and neck cancers
• Liver cancer
• Lung cancer
• Lymphoma
• Pancreatic cancer
• Pituitary gland tumors
• Sarcoma
• Tumors affecting the spine
• Tumors in the base of the skull

Approved in European Union as Proton Therapy for:

• Prostate cancer
• Brain tumors
• Breast cancer
• Cancer in children
• Eye melanoma
• Esophageal cancer
• Head and neck cancers
• Liver cancer
• Lung cancer
• Lymphoma
• Pancreatic cancer
• Pituitary gland tumors
• Sarcoma
• Tumors affecting the spine
• Tumors in the base of the skull

Who Is Running the Clinical Trial?

Thompson Cancer Survival Center

Lead Sponsor

Trials

4

Recruited

800+

Published Research Related to This Trial

A spot-reduced intensity-modulated proton therapy (IMPT) plan for a head-and-neck cancer patient successfully reduced the number of treatment spots by 96% (from 33,855 to 1,510) while maintaining comparable dosimetric quality.

This reduction led to a significant decrease in average delivery times by 46% (from 51.2 seconds to 27.6 seconds) without compromising treatment accuracy, demonstrating that spot-reduced IMPT can enhance efficiency in clinical settings.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Shortening delivery times for intensity-modulated proton therapy by reducing the number of proton spots: an experimental verification. van de Water, S., Belosi, MF., Albertini, F., et al.[2020]

Whole-pelvis pencil beam scanning (PBS) proton therapy is effective for treating prostate cancer, providing good target coverage while minimizing damage to surrounding organs at risk (OAR).

Two treatment planning approaches, conventional optimization (CO) and robust optimization (RO), were evaluated, with RO offering potential advantages in OAR sparing and efficiency, while CO remains a viable option for institutions lacking advanced capabilities.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Robust treatment planning in whole pelvis pencil beam scanning proton therapy for prostate cancer. Butala, AA., Ingram, WS., O'Reilly, SE., et al.[2021]

In a study involving three liver and two lung cancer patients, spot-reduced proton therapy plans decreased the number of treatment spots by 91%, leading to approximately 50% shorter delivery times without compromising the quality of the dose distribution.

The use of spot-reduced plans allowed for more rescans within the same time frame as conventional plans, which typically improved dosimetric parameters, although care must be taken to manage potential interference with the patients' breathing cycles during treatment.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Impact of spot reduction on the effectiveness of rescanning in pencil beam scanned proton therapy for mobile tumours. Bertschi, S., Krieger, M., Weber, DC., et al.[2022]

Proton therapy (PT), especially intensity modulated proton therapy (IMPT), shows superior treatment planning for prostate cancer by providing better homogeneity in the planning target volume (PTV) and sparing surrounding healthy tissues, such as the rectum, compared to traditional intensity-modulated radiation therapy (IMRT).

Proton therapy significantly reduces the dose to normal tissues outside the PTV, exposing them to less than 50% of the dose delivered by IMRT, making it a promising option for prostate cancer treatment in Australian facilities.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

A comparison of proton therapy and IMRT treatment plans for prostate radiotherapy. Dowdell, SJ., Metcalfe, PE., Morales, JE., et al.[2019]

In a study of 192 prostate cancer patients treated with proton beam therapy (PBT) over a median follow-up of 1.7 years, only 5 patients experienced grade 3 toxicity, with no occurrences of grade 4 or 5 toxicity, indicating a high safety profile for this treatment.

Patient-reported outcomes showed stable urinary function post-treatment, while sexual health scores declined slightly at 1 year but did not worsen thereafter; bowel function scores also decreased but stabilized, suggesting manageable side effects associated with PBT.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Early toxicity and patient reported quality-of-life in patients receiving proton therapy for localized prostate cancer: a single institutional review of prospectively recorded outcomes. Lee, HJ., Macomber, MW., Spraker, MB., et al.[2019]

In a study comparing proton beam therapy (PBT) techniques for prostate cancer, acute gastrointestinal toxicity rates were similar between pencil beam scanning (PBS) and passive scattering/uniform scanning (PS/US), with rates of 2.9% and 2.1% respectively.

However, PBS was associated with significantly higher acute genitourinary toxicity (21.9% vs. 15.1% for PS/US), indicating a need for further investigation into the safety profiles of these treatment methods.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Proton beam therapy delivered using pencil beam scanning vs. passive scattering/uniform scanning for localized prostate cancer: Comparative toxicity analysis of PCG 001-09. Mishra, MV., Khairnar, R., Bentzen, SM., et al.[2022]

In a study involving 30 prostate cancer patients, modifying proton beam therapy plans by deleting spots distant from the clinical target volume significantly reduced radiation exposure to organs at risk, such as the rectum and bladder.

The deletion of distant spots led to a decrease in the dose received by the rectum and bladder by approximately 2.4% and 2.3%, respectively, and a notable reduction of 15.9% to the urethral bulb, while not affecting the overall beam delivery time.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Simulation study using the spots deletion technique in spot scanning proton beam therapy for prostate cancers. Fukumitsu, N., Hayakawa, T., Yamashita, T., et al.[2021]

In a study of 10 patients undergoing proton therapy, it was found that random spot positioning errors had a more significant dosimetric impact on smaller tumor volumes, with a maximum dose variation of 1.88% observed in a brain tumor plan with a volume of 2.7 cm³.

For larger tumor volumes, such as a sacral chordoma plan (672 cm³), the dose variation dropped to only 0.3%, indicating that larger target volumes are less affected by positioning errors in proton therapy.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Dosimetric impact of random spot positioning errors in intensity modulated proton therapy plans of small and large volume tumors. Arjunan, M., Krishnan, G., Sharma, DS., et al.[2022]

Citations

1. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC8655742/

Simulation study using the spots deletion technique in ... The aim of the present study was to investigate the effects on the dose distribution and beam delivery time in spot scanning proton beam therapy (PBT)

2. sciencedirect.com sciencedirect.com/science/article/abs/pii/S036030160902803X

Spot Scanning Proton Beam Therapy for Prostate Cancer We propose a treatment planning approach and then analyze the consequences of various simulated alignment errors on prostate treatments.

3. withpower.com withpower.com/trial/phase-prostatic-neoplasms-2024-552c4

Proton Therapy Spot Placement for Prostate Cancer Studies have shown that spot deletion can decrease the dose to OARs and improve beam delivery time. Additionally, early toxicity and patient-reported quality-of ...

4. thegreenjournal.com thegreenjournal.com/article/S0167-8140(24)00635-2/abstract

Robustness evaluation of pencil beam scanning proton ... Compared to conventional radiotherapy using X-rays, proton therapy, in principle, allows better conformity of the dose distribution to target volumes, ...

5. floridaproton.org floridaproton.org/blog-spot/let-optimized-pencil-beam-scanning

Optimized Pencil Beam Scanning in Proton Therapy The study's results concluded that incorporating LET optimization with the targeted pencil beam scanning potentially increases the effectiveness ...

6. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC9238133/

Prostate Cancer Treatment with Pencil Beam Proton ... We report the early clinical outcomes of patients treated for localized prostate cancer using modern PBS–PBT with hydrogel rectal spacing and fiducial tracking