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'Watching' prostate cancer

Tuesday 17 March 2009

The Daily Mail has reported that “men diagnosed with low-risk prostate cancer can safely opt to have no treatment if they are closely monitored”. The newspaper said a US study found that most patients who chose to be monitored, under a method called ‘active surveillance’, did not experience a spread of the disease.

Active surveillance is already a NICE-recommended treatment option for men in the UK with low-risk, localised prostate cancer.

This study has some limitations in that it is a small observational study of men treated in the US. However, overall the study supports the NICE recommendation. Also, the study did not compare active surveillance with other treatment methods, but simply describes 262 men who were treated through an active surveillance approach for low-risk prostate cancer.

Where did the story come from?

Dr Scott E. Eggener and colleagues from the University of Chicago, Memorial Sloan-Kettering Cancer Center, the University of Miami, Cleveland Clinic Foundation, and the University of British Columbia carried out this research. It is not clear how the research was funded, although one author received a National Institutes of Health research award. The study was published in the peer-reviewed medical journal Journal of Urology .

What kind of scientific study was this?

In this case series study, the researchers reviewed and discussed the records of men who had undergone active surveillance for low-risk prostate cancer. Active surveillance involves close monitoring of serum PSA levels (prostate specific antigen – a marker for prostate cancer) and repeat prostate biopsies. It is a recognised treatment option for men with low-risk localised prostate cancer and, according to NICE guidance, even those who are considered suitable for radical treatment should first be offered this. The researchers were interested in what made men discontinue active surveillance and begin treatment. They were also interested in how many of them progressed to a more serious grade of cancer.

The researchers reviewed the records of 262 men aged 75 or younger who had attended one of four academic medical centres for treatment of low-risk prostate cancer between 1991 and 2007. To be eligible for inclusion in the study, their tumour had to either be too small to be felt or seen on scans, or be completely confined to the prostate and only in one half of one of the lobes. These features correspond to prostate cancer at clinical stages T1-T2a. Based on age and risk of cancer, each eligible individual had been offered multiple treatment options, and had chosen active surveillance.

The men were followed-up (retrospectively) from the date of their second biopsy for an average of 29 months. Several general health, urinary symptom checks, digital rectal examinations and PSA measurements were carried out every six to 12 months. Biopsies were recommended within 18 months of beginning active surveillance, followed by every one to three years, or if clinical examination had found notable changes. The researchers describe the characteristics of this population of cases, and then assess how many of the men remained on active surveillance during follow-up and what factors played a role in this.

What were the results of the study?

During the follow-up period, 157 (60%) of the men had at least one additional biopsy. There were 19 patients whose prostate cancer had progressed in grade (based on the Gleason score, which is a way to grade prostate cancer based on microscopic appearance of cells). These 19 men accounted for 7% of all patients and 12% of the 157 men who had at least one biopsy after beginning surveillance.

The researchers found that the men’s likelihood of discontinuing active surveillance was linked to the number of positive biopsy results they had, and whether their cancer was identified before they began active surveillance. The researchers say that the likelihood of staying on active surveillance after two years was 91%, and after five years was 75%. Of the 42 men who stopped surveillance, 26 had their prostate remove (prostatectomy).

What interpretations did the researchers draw from these results?

The researchers say that their study provides an overview of the experience of active surveillance in men with low-risk prostate cancer who were also candidates for other treatment options due to their estimated life expectancy. The researchers say that they have provided further evidence that for “highly select patients”, active surveillance is safe, durable and associated with a “low but finite risk of disease progression”.

What does the NHS Knowledge Service make of this study?

This retrospective case series describes the experiences of active surveillance in a group of men with low-risk prostate cancer. Interpretation of the results is limited in that the study is not a comparative study and did not compare active surveillance with other forms of treatment for men with these particular characteristics. An important point acknowledged by the researchers is that the study has a relatively short follow-up period, and the findings cannot be used to “justify active surveillance as a long-term management strategy”.

The researchers also point out that they may not be able to generalise their findings to other populations because this is a selected group of patients who were treated in particular ways at different treatment centres. The study was also conducted in the US, therefore the results are not directly applicable to practice in the UK.

Active surveillance is a NICE-recommended treatment option for men with low-risk localised prostate cancer. NICE is a regulatory body, and its recommendations about when to offer active surveillance are likely to be followed by most clinicians. Despite this study’s limitations, it reinforces this recommendation as a valid treatment option. However, this study should be interpreted as it is – an observational description of treatment patterns and short-term outcomes for a small group of patients treated in US medical centres.

Analysis by Bazian
Edited by NHS Website

Links to the headlines

When it's safer NOT to treat prostate cancer.

Daily Mail, 17 March 2009

Links to the science

Eggenera SE, Muellerb A, Berglundb RK, et al.

A Multi-Institutional Evaluation of Active Surveillance for Low Risk Prostate Cancer.

Journal of Urology 2009; published online 23 February