Study: New imaging technology shows promise in detecting of spread of prostate cancer

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Contents

At a glance Clinical trials
Strengths and limitations Guidelines              
What does this mean for me? Questions for your doctor 
In-depth Resources and reference

 

STUDIES AT A GLANCE

These studies are about:

How a new technology may be useful to detect spread of prostate cancer in men with newly diagnosed disease or in those whose cancer returns after treatment.


Why are these studies important?

Prostate cancer is the second most diagnosed cancer in men. About seven percent of all prostate cancers are in advanced stages (spread beyond the prostate) at the time of diagnosis.

After prostate cancer diagnosis, healthcare providers often order a series of tests to stage the cancer. Staging helps doctors determine how advanced the cancer is and whether it has spread beyond the prostate gland. Staging is used to make a treatment plan. Currently, doctors use standard imaging tests to stage prostate cancer, such as:  

  • X-rays
  • magnetic resonance imaging (MRI)
  • computed tomography (CT scan)
  • positron emission tomography (PET scan)

These tests can show if the cancer has spread to other organs. However, they sometimes do not detect spread of the disease.  


PET/CT scans

PET/CT scans combine two types of imaging—PET scans (positron emission tomography) and CT scans (computerized tomography)—in one test. PET/CT requires injection of a small amount of a radioactive drug known as a tracer. After injection, the tracer spreads through the body. The PET/CT scanners detect areas in the body where high amounts of the tracer are found. This allows doctors to to look for cancers and see how tissues and organs are working.


Prostate cancer risk groups

Most prostate cancer is found at an early stage. Most men with early-stage prostate cancer do well. However, some prostate cancers, even those that are early stage, may be more aggressive and have a higher risk for metastasizing (spreading) to other parts of the body.

Metastatic prostate cancer (cancer that has spread to other organs) requires more aggressive treatment and can lead to death. Doctors use standard tests to group prostate cancers by risk for recurrence and spread and use this information to guide treatment. The main risk goups include:

  • low risk
  • intermediate risk
  • high risk


OSPREY and CONDOR studies

Two research studies, OSPREY and CONDOR, looked at a new radioactive tracer called “18FDCFPyL PSMA.”

18FDCFPyL PSMA was created to bind a protein called prostate-specific membrane antigen (PSMA). PSMA is found at low levels on normal prostate cells, but it is found at high levels on prostate cancer cells. Because PSMA is found on the outside of prostate cells, it is being used by researchers to detect cancer and to develop treatments that directly target prostate cancer cells.

These studies compared the 18FDCFPyL PSMA screening technology to standard imaging for prostate cancer spread, which includes XRAY, MRI and CT. The studies looked at two groups of men:

  • men with newly diagnosed prostate cancer  
  • men whose cancer returned after treatment


OSPREY study findings

The OSPRY study included 268 men with high-risk prostate cancer.

All 268 participants had imaging with 18FDCFPyL PSMA.

  • 18FDCFPyL PSMA was much better than standard imaging at detecting the spread of prostate cancer in high-risk patients.
  • 18FDCFPyL PSMA found prostate cancer spread in 27% of men, compared with standard imaging, which found spread in less than 4% of men.


CONDOR study findings

The CONDOR study tested whether 18FDCFPyL PSMA was better at detecting prostate cancer that returned after treatment compared to standard imaging.

The study included 208 men with prostate cancer who were treated with androgen therapy (testosterone depleted) and received other treatments (prostatectomy, radiation therapy, etc.) for prostate cancer. Blood tests given to men after treatment suggested a return of cancer but could not be confirmed by standard imaging.

During the CONDOR study, participants underwent imaging with 18FDCFPyL PSMA.

  • Standard imaging did not detect return of cancer in any of the men (0 of 208 participants)
  • 18FDCFPyL PSMA detected the return of prostate cancer in about 66% of men (137 of 208 participants).


Side effects of 18FDCFPyL PSMA

Among the OSPREY and CONDOR studies, the most common side effects related to 18FDCFPyL PSMA tracer included:

  • headache
  • altered sense of taste (OSPREY)
  • fatigue (CONDOR) 


Strengths and limitations of the OSPREY and CONDOR studies

Strengths

  • The large study sample size allowed researchers to determine if the technology works in multiple patients and to observe if side effects are associated with its use.
  • For CONDOR, the sample population was restricted to men whose blood test suggested their prostate cancer had returned, which suggests that the technology may be useful in detecting recurring cancer.

Limitations

  • Despite finding more prostate cancers that spread, the studies do not show that use of 18FDCFPyL PSMA to find cancer spread earlier improves outcomes such as survival.
  • These research findings have not been published. The following limitations will likely be included in a publication:
    • Researchers did not mention how much time elapsed between standard imaging and imaging with 18FDCFPyL PSMA. It is possible that the cancer may have been limited to the prostate during standard imaging if much time had passed between the two procedures.
    • The studies did not mention race/ethnicity among patients. Medical procedures may work better or worse for people of different races and ethnicities. 


What does this mean for me?

In both studies, 18FDCFPyL PSMA detected more cases where cancer had spread beyond the prostate when compared with standard imaging. For OSPREY, the technique found almost eight times more metastases (spread of cancer) than standard imaging. For CONDOR, the technique found cancer spread 62 times more than standard imaging.

18FDCFPyL PSMA is not FDA-approved for use outside of research studies, and the OSPREY and CONDOR trials are completed. However, other clinical trials looking at 18FDCFPyL PSMA as a technology to detect prostate cancer are recruiting participants (see Clinical Trials below). If you are at high risk of developing advanced prostate cancer, talk to your healthcare provider to see if you may be eligible for an ongoing clinical trial.

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Posted 10/16/20

This article is relevant for:

Men with high-risk prostate cancer

This article is also relevant for:

Metastatic cancer

Healthy people with average cancer risk

Prostate cancer survivors

Newly diagnosed

People with a genetic mutation linked to cancer risk

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Questions to Ask Your Doctor

  • What is the best way to tell if my prostate cancer has spread?
  • What tests have already been done?
  • What were the results of these tests?
  • What, if any, additional testing should I have?
  • Do these tests have any side effects?
  • Is my prostate cancer low, intermediate or high risk?
  • How will these tests affect my medical options?
  • Do I meet criteria for genetic counseling and testing for an inherited mutation?
  • Can you refer me to a genetic counselor?
  • Can you provide a copy of my test results?
  • Should I consider a clinical trial?

Open Clinical Trials

Who covered this study?

Targeted Oncology

PyL PET tracer may be superior to standard imaging for prostate cancer This article rates 2.0 out of 5 stars

MedPage Today

PET spots prostate cancer mets missed on CT, MRI This article rates 5.0 out of 5 stars

How we rated the media

IN-DEPTH REVIEW OF RESEARCH

Study background:

While multiple imaging tests (e.g., X-rays, MRI, CT or bone scans) are FDA-approved as diagnostics to view the spread of prostate cancer, they are limited. Some imaging tests for prostate cancer have been observed to miss the spread of the disease, while other techniques have detected abnormalities that are unrelated, resulting in “false positives.”  

In the OSPREY and CONDOR clinical trials, researchers looked at 18FDCFPyL PSMA PET/CT as a possible imaging diagnostic to better detect prostate cancer and its spread to nearby organs compared with standard imaging.

18FDCFPyL PSMA uses positron emission tomography/computed tomography (PET/CT) imaging, which uses a radioactive drug to detect levels of prostate-specific membrane antigen (PSMA). The PSMA protein is normally found at a low level in normal prostate cells, but it is significantly increased in prostate cancer cells. PSMA can be detected in other organs as prostate cancer spreads.   

If 18FDCFPyL PSMA is confirmed by future studies to better detect the spread of prostate cancer to other organs, it could be a useful diagnostic for accurately staging the disease at initial diagnosis and relapse in men who were previously treated for the disease.  

Researchers of the studies wanted to know:

If 18FDCFPyL PSMA can locate the spread of prostate cancer in newly diagnosed men and in men whose cancer returned after treatment.


Study design and findings:

OSPREY

OSPREY was a phase 2 and 3 clinical trial that was held at 10 sites throughout the U.S. and Canada. The primary goal of the study was to test whether 18FDCFPyL PSMA PET/CT could detect spread of cancer to pelvic lymph nodes (organs near the prostate gland).

The study included 268 men, ranging from ages 46 to 84, with newly diagnosed high risk prostate cancer. Of these, 252 men were candidates for radical prostatectomy (complete removal of the prostate). Prior to the study, all participants had standard imaging to detect metastasis (spread) of cancer.

During the study, participants were given 18FDCFPyL PSMA by injection. Two hours prior to PET/CT scans, patients were injected with radioactive 18FDCFPyL PSMA that specifically targets PSMA throughout the body. (Data from PET/CT scans were tabulated by three PET/CT readers who were blinded to all participant clinical information.)

Among all 268 participants:

  • 18FDCFPyL PSMA PET/CT detected prostate cancer metastasis to nearby lymph nodes in 27% of men (72 of 268 participants), compared with standard imaging which detected spreading in about 4% of men.
  • Of the 72 men with metastatic cancer, 39 had cancers that spread only to nearby lymph nodes, while the other 33 men had cancers that metastasized to distant lymph nodes and other organs.

Among the 252 men in the study who had surgery to remove their prostate gland and nearby lymph nodes that could be looked at to confirm if the cancer had spread or not.

  • standard imaging showed 244 of 252 (almost 97%) had no cancer spread.
  • 18FDCFPyL PSMA detected prostate cancer in a total of 56 out of 252 (22%) patients. This changed the staging of their disease.

Most common side effects related to 18FDCFPyL PSMA included:

  • distorted sense of taste (dysgeusia)
  • headache

Strength of study

  • This study included a large sample size, which is needed to determine if the technology works in multiple patients and to observe if side effects are associated with its use.

Limitations of study

(Findings of this trial were presented at a meeting. Due to time constraints, presenters were not able to present all aspects of the study. Limitations listed below may be addressed in detail in a follow-up manuscript.)

  • The study did not include a placebo (control) group to control for false positives.
  • Researchers did not mention how much time elapsed between standard imaging and imaging with 18FDCFPyL PSMA. It is possible that the cancer may have been limited to the prostate during standard imaging if much time had passed between the two procedures.
  • The trial did not distinguish between people with or without an inherited mutation. Some medical treatment/procedures have been known to work better in people with specific mutations.
  • The study did not mention race/ethnicity among patients. Some races/ethnicities are more responsive to certain medical procedures than others.


CONDOR

CONDOR was a phase 3 multicenter clinical trial performed at 14 sites throughout the U.S. and Canada. The study’s primary endpoint was whether 18FDCFPyL PSMA has the capability to detect the return of prostate cancer in men who were previously treatmented for the disease.

The study consisted of 208 participants between ages 43 to 91 who were treated with androgen deprivation therapy (testosterone deficient) and received treatment for a previous diagnosis for prostate cancer by prostatectomy only, radiation therapy only, combined prostatectomy and radiation therapy, or other systematic therapy.

Blood tests were given to the men during posttreatment follow-ups. Increases in prostate-specific antigen (PSA) levels that were greater than two nanograms/milliliters suggested possible return of cancer. At the start of the study, patients underwent standard imaging and completed questionnaires about their plans to treat relapse.

During the trial, participants underwent imaging with 18FDCFPyL PSMA PET/CT. They were injected with nine millicuries of the radioactive drug 18FDCFPyL PSMA one to two hours prior to having PET/CT scans.

The results showed that 18FDCFPyL PSMA PET/CT was able to detect cancer relapse in about 62 percent of participants, whereas standard imaging methods did not detect any return of cancer among participants. Results of 18FDCFPyL PSMA scans led 64 percent of participants to change their plans to treat relapse.

The most common side effects related to 18FDCFPyL PSMA PET/CT included:

  • fatigue
  • headache

Strengths of study

  • The study included a large sample size, which is needed to determine if the technology works in multiple patients and to observe if side effects are associated with its use.
  • The study included only men whose blood analysis suggested relapse of prostate cancer.

Limitations of study

(Findings of this trial were presented at a meeting. Due to time constraints, presenters were not able to present all aspects of the study. Limitations listed below may be addressed in detail in a follow up manuscript.)

  • The study did not include a placebo (control) group to control for false positives.
  • No information was given about which standard imaging procedures were used in the study. This is critical to make a fair comparison between 18FDCFPyL PSMA PET/CT imaging and a specific standard imaging technology.
  • The trial did not distinguish between people with or without inherited mutations. Some medical treatment/procedures have been known to work better in people with specific mutations.
  • The study did not mention race/ethnicity among patients. Some medical procedures may work better or worse for people of different races and ethnicities. 


Context:

Detecting the spread of prostate cancer to other organs is necessary to accurately stage and determine the severity of the disease. More accurate staging can help men make better decisions on treatment options for prostate cancer. Based on the studies’ findings, 18FDCFPyL PSMA PET/CT detected almost eight times more metastases among OSPREY participants and 62 times more cancer among CONDOR participants when compared with standard imaging. These data suggest that newer diagnostics are needed to improve the standard processes for staging and detecting the spread of prostate cancer.


Conclusions:

OSPREY and CONDOR clinical trials looked at the capability of 18FDCFPyL PSMA PET/CT to detect prostate cancer in newly diagnosed men and in castrated men who relapsed after prostate cancer treatment. If confirmed in future studies, imaging techniques that detect the increase and spread of PSMA using PET/CT scans could be better methods to determine metastasis and staging of prostate cancer compared with standard imaging.

Posted 10/16/20

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