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

500 Participants Needed

Trial Summary

What is the purpose of this trial?

This purpose of this study is to examine the placement of proton spots during pencil beam scanning proton therapy for low and intermediate risk prostate cancer. The researchers will test a unique technique called "Spot Delete" to control the placement of spots during treatment planning. They will also use a special computer model to study how the energy of the proton beam (linear energy transfer) is related to rectal and bladder side effects. The study involves creating a treatment plan based on a CT scan, which helps guide the proton beam in the body. The clinical team uses this CT scan to find the best placement for the protons. The "Spot Delete" method prevents protons from stopping in the rectum, sigmoid, and small bowel, which is thought to be related to acute or late toxicities, such as tenesmus, diarrhea, fecal incontinence, proctitis, and rectal hemorrhage.

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 data supports the idea that Proton Therapy Spot Placement for Prostate Cancer is an effective treatment?

The available research shows that Proton Therapy Spot Placement for Prostate Cancer can effectively target the cancer while reducing the impact on surrounding healthy organs. For example, one study found that by deleting certain spots in the treatment plan, the dose to nearby organs like the rectum and bladder was reduced, which means less potential damage to these areas. Another study highlighted that reducing the number of spots can shorten treatment times without losing effectiveness, making the therapy more efficient. These findings suggest that Proton Therapy Spot Placement is a promising option for treating prostate cancer, offering precise targeting and potentially fewer side effects compared to traditional methods. ^{1 2 3 4 5}

What data supports the effectiveness of Proton Therapy Spot Placement for Prostate Cancer?

Research shows that using spot reduction in proton therapy can significantly shorten treatment times without compromising the quality of the treatment plan. Additionally, deleting spots that are far from the target area can reduce the dose to nearby organs, potentially lowering side effects. ^{1 2 3 4 5}

What safety data is available for proton therapy spot placement in prostate cancer treatment?

The safety data for proton therapy spot placement, including techniques like spot deletion and pencil beam scanning, indicate that these methods can reduce dose exposure to organs at risk (OAR) such as the rectum and bladder, without compromising the treatment's effectiveness. 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-life outcomes from proton therapy for prostate cancer have been prospectively recorded, suggesting manageable toxicity levels. Comparative analyses also highlight the dosimetric benefits of pencil beam scanning over traditional methods, although more data is needed to fully understand the comparative toxicity rates. ^{2 3 4 6 7}

Is proton therapy, including spot placement techniques, generally safe for humans?

Proton therapy, including techniques like spot placement, has been studied for safety in treating prostate cancer. Research shows that modifying the treatment plan can reduce radiation exposure to nearby organs, suggesting a focus on minimizing side effects. Additionally, early toxicity and patient-reported outcomes indicate that proton therapy is generally well-tolerated. ^{2 3 4 6 7}

Is Spot Delete planning for proton therapy a promising treatment for prostate cancer?

Yes, Spot Delete planning for proton therapy is promising for prostate cancer. It can reduce treatment time by cutting down the number of proton spots without losing quality. This method also helps protect healthy organs and tissues from unnecessary radiation, making it a safer option. ^{1 2 3 5 8}

How does the Proton Therapy Spot Placement treatment for prostate cancer differ from other treatments?

Proton Therapy Spot Placement for prostate cancer is unique because it uses a technique called 'spot deletion' to reduce the number of proton spots, which shortens delivery times without compromising the quality of the treatment plan. This approach allows for more efficient treatment sessions and potentially better sparing of healthy organs compared to traditional photon beam therapy. ^{1 2 3 5 8}

Research Team

Samantha Hedrick, PhD

Principal Investigator

Thompson Proton Center

Eligibility Criteria

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.

I have had a physical exam to determine the stage of my cancer.

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

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

Treatment Details

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.

Participant Groups

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+

Findings from Research

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]

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]

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]

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]

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]

References

1. United States pubmed.ncbi.nlm.nih.gov

Robust treatment planning in whole pelvis pencil beam scanning proton therapy for prostate cancer. [2021]

2. England pubmed.ncbi.nlm.nih.gov

Impact of spot reduction on the effectiveness of rescanning in pencil beam scanned proton therapy for mobile tumours. [2022]

3. England pubmed.ncbi.nlm.nih.gov

Simulation study using the spots deletion technique in spot scanning proton beam therapy for prostate cancers. [2021]

4. England pubmed.ncbi.nlm.nih.gov

Dosimetric impact of random spot positioning errors in intensity modulated proton therapy plans of small and large volume tumors. [2022]

5. England pubmed.ncbi.nlm.nih.gov

Shortening delivery times for intensity-modulated proton therapy by reducing the number of proton spots: an experimental verification. [2020]

6. England 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. [2019]

7. Ireland 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. [2022]

8. Netherlands pubmed.ncbi.nlm.nih.gov

A comparison of proton therapy and IMRT treatment plans for prostate radiotherapy. [2019]