The 71-year-old with a ‘normal’ PSA test result
Every GP has to go through lists of laboratory results looking out for the abnormal ones. But what happens when a ‘normal’ reading is anything but for that particular patient? Dr Sabby Kant remembers such a case
Every GP has to go through lists of laboratory results looking out for the abnormal ones. But what happens when a ‘normal' reading is anything but for that particular patient? Dr Sabby Kant remembers such a case
It was a busy morning and in the spare few minutes between patients, I was quickly filing my ‘normal' lab links results, leaving the abnormal ones to analyse later.
It just so happened that the next patient had come in to discuss and collect his latest PSA results. He wanted a copy of the results to take to his private consultant.
Earlier that morning I'd filed a number of PSA results falling within normal range. This patient's PSA result of 1.4ng/ml seemed normal and was filed into his records.
But this patient was a 71-year-old man who had presented 18 months before with a four-month history of obstructive urinary symptoms. Rectal examination had revealed a unilateral lobular firm asymmetrical prostate and his PSA had been 7ng/ml. He was fast-track referred to the local urologist as a suspected cancer case. Subsequent prostate biopsies confirmed prostate cancer and he was offered either radiotherapy or radical surgery with radiotherapy.
After seeking a second opinion, the patient had opted for radical prostatectomy done privately, which was successful and his consultant was confident that he had removed most – if not all – of the prostate. The patient was further encouraged that he was spared from incontinence.
Following the operation he underwent a course of post-operative radiotherapy. Since treatment his PSA had remained suppressed and unmeasurable at less than 0.01ng/ml. The patient had to travel some distance into central London for his subsequent private follow-ups.
However, as having a private blood test necessitated an extra trip into London prior to his appointment with the consultant, he had of his own accord requested the PSA level to be done by his GP. His plan was to take the results to his consultant. Hence his appointment to see me to collect a copy of the PSA result.
The patient's PSA might have been in the normal range but was highly abnormal for him. His result of 1.4ng/ml, though seemingly normal, represented a more than 14-fold rise over a period of five months. This strongly suggested the possibility of cancer regrowth.
A repeat PSA done by his private consultant's laboratory confirmed this rise and he underwent further radiological scanning. This confirmed regrowth of cancer in the prostatic bed.
The patient was subsequently treated by a further course of radiotherapy to the prostatic bed together with anti-androgen cover. His PSA within six months dropped back to 0.3ng/ml. Throughout this episode he remained surprisingly asymptomatic with respect to urinary symptoms.
Why it nearly went wrong
The normal range of PSA levels for our laboratory is automatically graded according to the patient's age. For this patient, the normal range was stated as less than 6.6ng/ml.
Most PSA tests performed in primary care are performed on symptomatic patients presenting with obstructive uropathy or as a screening test, albeit a controversial one.
With the increasing prevalence of prostate cancer, a significant number of patients in primary care have undergone treatment or are on surveillance. And for these patients, interpretation of the PSA requires careful study of their history and PSA trend. So every PSA result requires the clinician to look at the individual's records and hospital letters closely.
After a successful procedure such as radical prostatectomy, most if not all the prostate is removed. The postoperative PSA is normally unrecordable or extremely low (such as 0.01ng/ml).
Any increase, particularly a fast rise, should raise alarm bells about the likelihood of tumour regrowth from microscopic cancer cells left after surgery.
The problem is that the busy clinician is faced with hundreds of test results from lab links on a daily basis. Laboratories often highlight results in bold if they fall out of range to warn the clinician. But this does not help in post radical prostatectomy cases as results look normal – indeed, reassuringly low.
The moral of the story
For PSA levels, ‘normal' may not be normal, so double check the patient's clinical history. Check for a history of prostate cancer. Checking the PSA trend is fairly easy and can help identify aberrant results. This may be tedious when faced with hundreds of lab test results but could prevent a major disaster.
Dr Sabby Kant is a GP in Hillingdon, north-west LondonHave you had a Near Miss? Have you had a Near Miss?
If you've had a case where something nearly went badly wrong - but didn't - and you feel other GPs could learn from it, please contact Pulse clinical editor Adam Legge on 020 7921 8097 or email him at email@example.comNear miss - 71 year old patient with abnormal PSA test