Call for better use of prostate cancer biopsies

Routine collection of additional information from prostate cancer biopsies could allow better decisions about the best choice of treatment, according to a study published in the journal Cancer*.

Through a systematic review of the published evidence, scientists funded by the NHS Cancer Screening Programme, Cancer Research UK and Cancer Research Wales found evidence of a link between the spread of cancer to nerves in the prostate gland – called ‘perineural invasion’ or PNI – and a poorer outlook for prostate cancer patients.

The clinical significance of PNI has been unclear, and therefore current guidelines for pathologists make no mention of PNI, leaving it up to individual doctors to decide whether they check for it or not.

This review shows a significant association between PNI and the risk of disease recurrence but the risk associated with PNI remains impossible to fully quantify from the few studies that have been done so far. The researchers are recommending to the Royal College of Pathologists that PNI should be assessed in every case of prostate cancer. This would help determine more precisely the size of the associated risk and so aid future decisions about treatment.

Prostate cancer is the most common cancer in men, with more than 32,000 cases diagnosed each year in the UK, but the best approach to treatment is not always clear. Doctors currently have very little evidence to rely on when deciding on the most appropriate treatment option.

Widespread use in the US of the PSA (Prostate-Specific Antigen) test to identify asymptomatic prostate cancer has led to an increase in the number of prostate tumours detected, but the PSA test gives only limited information regarding a patient’s prognosis.

The best management of early diagnosed tumours is particularly hard to judge. Options include radical prostatectomy – surgical removal of the prostate – and active surveillance or so-called ‘watchful waiting’, which may be chosen on the basis that most prostate tumours are slow-growing and occur in elderly men in whom prostate cancer will not be their cause of death. If, however, the cancer turns out to be growing faster, then active treatment is offered.

Cancer Research UK’s Dr Patricia Harnden, lead author of the report, said: “We’ve shown that PNI increases the risk of recurrence in prostate cancer. If it is found in a prostate biopsy, it could mean the difference between choosing ‘watchful waiting’ and immediately treating the cancer, or perhaps giving a longer course of therapy. Pathology is not being used to its full potential in prostate cancer if PNI is not looked for.

” Making PNI a mandatory reporting item in the guidelines of the Royal College of Pathologists would have two effects – it would help gather more data on the exact association between PNI and risk of recurrence, and it would enable doctors to make more informed decisions on how best to treat their patients. We must also ensure that future studies of pathological prognostic factors such as PNI are designed well enough to properly assess their significance.”

Julietta Patnick, director of NHS Cancer Screening Programmes, said: “I am very pleased that the NHS Cancer Screening Programmes has been able to facilitate this significant work. The results of this review will assist health professionals in making the best treatment decisions for patients.”

Professor John Toy, medical director of Cancer Research UK, said: “Some prostate cancer patients have normal PSA levels, and some healthy men have high PSA levels that are not caused by cancer. It can often be extremely difficult to predict with certainty the prognosis for many men with early prostate cancer.

“Therefore, the identification of a prognostic marker that indicates an aggressive cancer would be of great value. PNI in a prostate biopsy may be such a marker. We must ensure that no opportunity to gather potentially important information about prostate cancer is wasted.”

Professor Adrian Newland, president of the Royal College of Pathologists, said: “The Royal College of Pathologists welcomes this systematic review of PNI in prostatic cancer biopsies, particularly the identification of PNI as a reliable predictor of adverse clinical outcome.

“Detailed histological evaluation by medically-trained histopathologists is essential in the assessment of cancer specimens, particularly the identification of features of clinical value to patients and their supervising clinicians alike. The Royal College of Pathologists endorses the view expressed in the paper that well designed studies using pre-defined stringent protocols are now required to provide robust objective estimates of risk, following identification of PNI in prostatic core biopsies, as an aid in the planning of treatment for men diagnosed with prostate cancer.”

ENDS

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