Results Summary
What was the research about?
Men treated for prostate cancer usually have prostate-specific antigen, or PSA, blood tests as part of their follow-up care. This test helps detect if prostate cancer has returned. But doctors differ in how often they recommend that men have follow-up PSA tests.
In this project, the research team did two studies that looked at men with prostate cancer who differed in how often they received PSA tests in the first year after treatment. They studied whether more PSA tests led to better health outcomes.
What were the results?
Study 1. The research team compared groups of men who had either zero or one, two, or three or more PSA tests in the first year. The three groups didn’t differ in
- Survival
- Rate of prostate cancer returning
- How soon doctors detected cancer that came back
Study 2. Anxiety, overall quality of life, and quality of life related to their cancer didn’t differ based on the number of PSA tests men had in the first year.
Who was in the study?
Study 1. The research team used records from the National Cancer Data Base. The records included 10,479 men diagnosed with prostate cancer between 2005 and 2010. These men had radiation or surgery to treat the cancer. Of the men, 72 percent were white, 13 percent were African American, and 15 percent were another race or Hispanic. The average age was 63.
Study 2. The team used surveys from 835 men diagnosed with prostate cancer between 2011 and 2013 who participated in the North Carolina Prostate Cancer Comparative Effectiveness and Survivorship Study. These men had radiation or surgery to treat the cancer. Of these men, 66 percent were white, 30 percent were African American, and 4 percent were another race or Hispanic. The average age was 63.
What did the research team do?
Study 1. The research team grouped men based on whether they were at low, medium, or high risk of their cancer coming back, and if they had surgery or radiation. The team then sorted men into three categories based on how many PSA tests they had the first year. Then they compared health outcomes across these categories.
Study 2. Men completed surveys about anxiety related to prostate cancer and quality of life once a year for five years. The research team sorted men based on how many PSA tests they had the first year. The team then compared changes in anxiety and quality of life across the three categories.
Prostate cancer survivors and cancer doctors helped plan the study.
What were the limits of the study?
Patients may have had more or fewer tests in later years than they did in the first year. The first study had fewer men than planned, making it hard to find differences in survival or cancer return rates. In the second study, fewer men answered surveys over time, which could make results less accurate.
Future research could follow patients for longer.
How can people use the results?
Prostate cancer survivors and their doctors can use these results when considering how often to schedule PSA testing after treatment.
Professional Abstract
Objective
(1) To compare the effects of different frequencies of prostate specific antigen (PSA) surveillance after prostate cancer treatment on health outcomes; (2) To compare the effects of different post-treatment PSA surveillance frequencies on patient-reported anxiety and quality of life
Study Design
| Design Element | Description |
|---|---|
| Design | Observational: cohort study |
| Population |
Study 1: 10,479 men in the National Cancer Data Base with newly diagnosed localized prostate cancer between 2005 and 2010 who were treated with radiation therapy or radical prostatectomy and had complete follow-up through 2015 Study 2: 835 men with newly diagnosed localized prostate cancer between 2011 and 2013 treated with radiation therapy or radical prostatectomy who have been followed prospectively in the North Carolina Prostate Cancer Comparative Effectiveness and Survivorship Study |
| Interventions/ Comparators |
Number of PSA tests in the first year after prostate cancer treatment: 0–1; 2; 3+ |
| Outcomes |
Study 1: overall survival, time to recurrence, treatment for recurrent cancer Study 2: patient-reported anxiety, cancer-specific health-related quality of life, global health-related quality of life |
| Timeframe |
Study 1: median 8 years of follow-up Study 2: 5-year follow-up |
Study 1. This observational cohort study used data from the National Cancer Data Base to compare three post-treatment PSA testing frequencies on overall survival and recurrence among 10,479 men with localized prostate cancer treated with surgery or radiation therapy. Of these men, 72% were non-Hispanic white, 13% were African American, and 15% were another race and/or Hispanic ethnicity. The average age was 63.
Researchers stratified men into six groups based on their low, medium, or high risk of prostate cancer recurrence and their initial treatment for prostate cancer, either surgery or radiation therapy. For all six strata, researchers categorized men into one of three comparator groups based on the number of PSA tests they received in the first year after treatment (zero or one, two, or three or more). Within each stratum, researchers compared study outcomes among the PSA testing frequencies.
Study 2. This study used data from the North Carolina Prostate Cancer Comparative Effectiveness and Survivorship Study to compare the effect of three post-treatment PSA testing frequencies among 835 men with localized prostate cancer who received initial treatment with surgery or radiation therapy. Of these men, 66% were non-Hispanic white, 30% were African American, and 4% were another race and/or Hispanic ethnicity. The average age was 63 years.
Men completed surveys about prostate cancer-specific and global quality of life at enrollment, 3 and 12 months, and then annually thereafter; questions about prostate cancer-related anxiety began at 12 months. Researchers compared changes in these outcomes through five years of follow-up among the PSA testing frequencies.
Prostate cancer survivors and oncologists helped plan the study.
Results
Objective 1. In each of the six strata, researchers found no significant differences in overall survival, time to prostate cancer recurrence, or treatment for prostate cancer recurrence among the three post-treatment PSA testing frequencies.
Objective 2. Changes in patient-reported anxiety and prostate cancer-specific and global quality of life did not differ significantly by frequency of post-treatment PSA testing.
Limitations
The first-year PSA testing frequencies may not reflect testing frequencies in subsequent years. Study 1 may have been underpowered to detect meaningful differences in overall survival over a median follow-up of eight years. In study 2, response rates for patient-reported measures decreased with longer follow-up, leading to missing data that could bias results.
Conclusions and Relevance
Frequency of PSA testing in the first year after treatment with surgery or radiation therapy was not associated with differences in overall survival, detection of recurrence, or changes in prostate cancer-related anxiety or quality of life in men with localized prostate cancer.
Future Research Needs
Future research could follow patients for longer to evaluate the association between frequency of post-treatment PSA testing and prostate cancer recurrence or overall survival.
Final Research Report
View this project's final research report.
Peer-Review Summary
Peer review of PCORI-funded research helps make sure the report presents complete, balanced, and useful information about the research. It also assesses how the project addressed PCORI’s Methodology Standards. During peer review, experts read a draft report of the research and provide comments about the report. These experts may include a scientist focused on the research topic, a specialist in research methods, a patient or caregiver, and a healthcare professional. These reviewers cannot have conflicts of interest with the study.
The peer reviewers point out where the draft report may need revision. For example, they may suggest ways to improve descriptions of the conduct of the study or to clarify the connection between results and conclusions. Sometimes, awardees revise their draft reports twice or more to address all of the reviewers’ comments.
Peer reviewers commented and the researchers made changes or provided responses. Those comments and responses included the following:
- The reviewers asked why overall survival was chosen as the primary outcome to measure rather than counting deaths specifically caused by prostate cancer. The researchers explained that the database they used provided data on overall survival only and not the cause of death.
- The reviewers asked for more discussion about the effects of race, ethnicity, and socioeconomic status on the frequency of prostate-specific antigen (PSA) surveillance. The researchers agreed that post-cancer treatment surveillance should reflect risk factors that affect recurrence rates. The researchers commented that race appears to be an independent risk factor and added a paragraph about the effects of race to the report’s background section. However, the researchers declined to add a discussion about socioeconomic status, which they said does not appear to be an independent risk factor when race and other factors are also considered.
- The reviewers asked how the researchers accounted for changes in treatment modality in their cohorts. The researchers stated that in one cohort, they did not record specific treatment characteristics and would not have been able to compare groups based on these characteristics because of small numbers in each group. In the second cohort, the researchers did collect treatment modality information, but they found that the time period for tracking that cohort was too short to see significant changes in treatment modality over time.
- The reviewers asked if the study looked at how frequency of clinic visits affected PSA surveillance and outcomes. The researchers said that they did not have data regarding patients’ physician visits, so they could not evaluate whether the frequency of visits correlated with testing frequency, cancer recurrence, or survival.
- The reviewers said that an important problem with this study is that they powered the study to detect a 7 to 10 percent difference in mortality between groups of patients. The reviewers pointed out that this is a very ambitious expectation in a sample of patients who already had prostate cancer and had viable options to treat co-occurrences and prevent death. The researchers stated that they had originally planned the study to include about 14,000 patients and to have the ability to detect a 5 percent difference in survival. Unfortunately, the researchers were unable to recruit a sample of that size, so they needed a larger difference between groups to find it to be statistically significant.
Conflict of Interest Disclosures
Project Information
Key Dates
Study Registration Information
^This project was previously titled: Determining How Often Prostate Cancer Survivors Should Get Follow-up Testing