Managing prostate cancer in primary care
According to the Singapore National Registry of Diseases Office (NRDO), prostate cancer is the third most common cancer and the sixth most common cause of cancer-related deaths affecting men in Singapore. Dr Daniel Tan, radiation oncologist and medical director of Asian American Radiation Oncology at Gleneagles Hospital, Singapore, speaks to Roshini Claire Anthony on the importance of early detection of prostate cancer and the challenges associated with diagnosing and treating this condition.
Prostate cancer in its early stages is curable with many treatment options available. Hence, early detection is essential for patients to have the best chance of cure and also to have the option of the widest range of therapeutic options based on their acceptance of each side effect profile.
Prostate cancer is often silent in its early stages. Patients may present with urinary symptoms of obstruction such as hesitancy, dysuria, frequency, nocturia, poor stream, and occasionally, haematuria. In the GP clinic, digital rectal exam (DRE) and prostate-specific antigen (PSA) testing are useful in picking up prostate cancer. Patients with suspicious results are then referred to an urologist for a prostate biopsy to confirm the diagnosis.
There is controversy over routine population-based screening for prostate cancer, mainly because it has not been shown to save lives and may also lead to extra tests and treatments which may be harmful to those who undergo them.
Anecdotally, most oncologists have treated the screening-diagnosed prostate cancer patient which demonstrates that screening does pick up asymptomatic prostate cancers. The problem is what may work for an individual may not benefit the population at large. Thus, patients who wish to pay for their own prostate cancer screening may do so after being adequately counselled about the pros and cons of doing so.
Men who are at higher risk of prostate cancer (eg, those who have a familial history due to faulty genes) may benefit from regular PSA screening. This is still an ongoing research question.
The main challenge in diagnosing prostate cancer is that presenting symptoms are similar to other conditions such as benign prostate hyperplasia, prostate infection (prostatitis), or physiological activities such as exercise or sexual activity. This may result in false alarms which may lead to unnecessary anxiety and additional tests for the patient. GPs can overcome these by adequately counselling patients (before they undergo screening) about the possible outcomes and tests, and for patients not to be unduly alarmed until a final diagnosis is made.
Prior to commencing treatment, patients should be adequately worked up and staged so that the appropriate treatments can be determined. GPs should refer patients to an urologist for a transrectal ultrasound (TRUS)-guided biopsy to confirm the diagnosis and thereafter refer their patients to the various treating specialists for an informed discussion of the most appropriate treatment option. Given that there are different treatments which are equally effective for prostate cancer, it is important for patients to understand the available options and their possible side effects before making their decision.
Treatment of prostate cancer varies from active surveillance in early, low-risk prostate cancers, to radical prostatectomy or radiation therapy alone or in combination with hormonal therapy in localized prostate cancer, to hormonal therapy or chemotherapy in late, advanced prostate cancer.
There are different types of radiation therapy such as internal radiotherapy (brachytherapy), external beam radiotherapy in the form of intensity-modulated radiation therapy or stereotactic body radiation therapy, and proton beam therapy. Each of these treatment options has their own efficacy, cost, duration, and side effect profile.
Recently, a new scanning technique called multi-parametric Magnetic Resonance Imaging (mpMRI) was shown to be able to better identify men who would benefit from a prostate biopsy among those screened using PSA and DRE. Furthermore, the ability to visualize the suspicious nodules within the prostate using this scan enables the biopsy to be more focused. Finally, the MRI scan would also demonstrate the extent of tumour invasion, which will help specialists decide whether surgery or radiation is a better treatment option for the patient.
GPs should keep in contact with the treating specialist to be updated of their patient’s treatment details and expected side effects. The treating specialist will be able to advise the GP what side effects to look out for and how to optimally manage them.
Society for Men’s Health Singapore
National Comprehensive Cancer Network (NCCN)
European Society for Medical Oncology (ESMO)
Prostate cancer is increasing in incidence due to an ageing population as well as the widespread practice of PSA screening. Not all prostate cancers need to be treated and for those which need treatment, many equally effective modern treatments exist. These options vary in cost, duration, and side effect profile, and patients should be given their full options so that they will receive the most appropriate treatment and the option they are most comfortable with. GPs can work together with the patient’s urologist or radiation oncologist to understand the patient’s condition so as to provide seamless continuum of care from the point of diagnosis to treatment and post-treatment surveillance.