September is Prostate Cancer Awareness Month. According to the Malaysia National Cancer Registry 2012-2016, prostate cancer ranks third in terms of the incidence among adult males.
The registry also noted an increased number of males presented at an advanced stage of the disease (Stage 4) in comparison to a previous time period (2007 to 2011).
As such, screening is recommended for Malaysian men aged 50 and older in order to identify the disease at an early, curable stage.
Screening for prostate cancer is done by a simple blood test known as the prostate-specific antigen (PSA) test. Men also undergo a digital rectal examination (DRE) to examine the prostate gland in the clinic.
The American Urology Association suggests that most men should receive a baseline PSA test between ages 45 to 50 years. Men with a family history or who are at increased risk of prostate cancer, should talk to their doctor about screening earlier.
For men in their 60s, a PSA score greater than 4.0 ng/ml is considered abnormal. A PSA score may also be considered abnormal if it rises a certain amount in a single year.
Only a prostate biopsy can definitively diagnose prostate cancer. Traditionally, this is carried out by a transrectal ultrasound (TRUS) guided biopsy of the prostate gland.
Recently, multiparametric-MRI (mp-MRI) of the prostate gland has been used that increases the accurate localisation of prostate cancer at the time of MRI targeted biopsy.
Radiotherapy is a locally focused, non-surgical curative intervention that is highly effective for prostate cancer in its early stages. It has a comparable cure rate to prostatectomy, with additional benefit of having minimal impact on urinary continence and fewer long-term sexual adverse effects.
One modality of radiotherapy is the highly precise stereotactic body radiation therapy (SBRT), which administers substantial daily radiation doses to the prostate with fewer treatments compared to traditional radiotherapy.
To achieve this, modern imaging modalities like mp-MRI and prostate specific membrane antigen-positron emission tomography (PSMA-PET) scans are used in combination with state-of-the-art SBRT planning, imaging and treatment delivery technology.
By optimising radiation dose delivery to prostate cancer cells, cure rates can be enhanced while doses to healthy tissues are minimised. Consequently, treatment-related toxicity and adverse effects can be substantially reduced.
SBRT has been shown to be safe and effective in treating prostate cancer in several studies, with safety and efficacy rates similar to traditional radiation therapy methods.
SBRT eliminates cancerous tissue with only five treatments administered over a period of one week. The expedited timetable is attractive to patients as it offers greater convenience than the conventional radiation regimen, which necessitates daily treatments for a duration of four to eight weeks.
Many studies employing SBRT reported that patients with low-risk, intermediate-risk, and high-risk localised prostate cancer had five-year biochemical (prostate specific antigen, PSA) progression-free survival rates of 95 per cent, 84 per cent, and 81 per cent respectively.
Fatigue, urinary and bowel irregularities, and fatigue are frequent adverse effects of SBRT for the prostate that are typically reversible and transient in nature.
There is a subset of patients with a restricted number of detectable metastases (1–5 sites, predominantly bone and nodal metastases), known as oligometastatic prostate cancer.
In these patients, SBRT targeted at prostate cancer and metastases identified by PSMA-PET scan has the potential to be a curative treatment option.
Additionally, SBRT can be combined with systemic therapies such as hormone therapy and chemotherapy to effectively eliminate micrometastases. SBRT exhibits considerable potential as a salvage treatment alternative for intraprostatic recurrence following conventional radiotherapy as well as prostate bed recurrence following prostatectomy.
The ProtecT (Prostate testing for cancer and Treatment) trial established that survival from clinically localized prostate cancer remains very high over a median of 15 years (about 97 per cent), irrespective of treatment allocation i.e., active monitoring, radical prostatectomy, or radical radiotherapy.
Therefore, the choice of therapy involves weighing the pros and cons of each treatment against the individual patient’s needs.
SBRT’s toxicity versus surgery for localised prostate cancer was established in the PACE-A trial, where at two years post procedure, patients receiving SBRT reported better urinary continence and less sexual bother compared with those who underwent surgery. However, SBRT patients reported more bowel bother symptoms than surgery patients.
SBRT was compared to traditional radiotherapy in the PACE-B trial and the efficacy were equivalent between the two arms (around 95 per cent at five years) with similar toxicity.
The investigators concluded that taking PACE-A and B together, that SBRT should be the new standard of care for low and intermediate risk localised prostate cancer. Patients being offered surgery should be given information from these trials before deciding on treatment options.
In conclusion, SBRT is an established, high precision radiation treatment modality for early stage and advanced prostate cancer.
With the availability of the highly sophisticated linear accelerator radiotherapy systems in Malaysia, this gives hope for prostate cancer patients and their families of greater chance of cure and better quality of life after treatment with SBRT. This is certainly the expectations of cancer patients of the 21st century.
Dr Aminudin Rahman Mohd Mydin is a consultant clinical and radiation oncologist at KPJ Damansara Specialist Hospital.
- This is the personal opinion of the writer or publication and does not necessarily represent the views of CodeBlue.
