There are 4 stages of Prostate Cancer. Stages 1 and 2 relate to the situation in which the cancer is found entirely within the Prostate Gland. Stage 3 is where the cancer has broken out of the Prostate Gland but is still local to that gland. In all these cases the treatment aims to cure the cancer completely. In many cases it does not recur when initially cured, but a recurrence can occur even after many years – and this recurrence may involve cancer which has moved out of the vicinity of the Prostate Gland and into other parts of the body. This is Stage 4.
If left undiagnosed and untreated for too long Prostate Cancer can also be at Stage 4 when first diagnosed and this is why it is wise to have your PSA measured regularly once you are over 50 years of age – or before if in a high risk category.
Stage 4 has no known “complete cure”. When Prostate Cancer is diagnosed as Stage 4 there are cancerous growths at one or more sites within the body, typically in Lymph Nodes and the Bones. These growths are called “Metastatic Disease”, often referred to as “Secondaries”. At this time, there is no known “cure” for metastatic prostate cancer, and the primary treatments such as Radiotherapy, Brachytherapy and Prostatectomy which are targeted at the Prostate Gland and its local area are not suitable to handle metastatic disease.
Chemotherapy can be used in this instance. A chemical compound that kills cancer cells is either taken by mouth or injected into the body and this chemical spreads throughout the body, substantially killing metastatic growths. Chemotherapy typically involves several day hospital treatments at intervals of a few weeks. Afterwards, the PSA level drops and this is called “remission”. Unfortunately this process does not remove the capacity for these metastatic centres to continue to grow. Consequently, after Chemotherapy has been used a check is kept on the patient so that when the metastatic centres reappear another round of Chemotherapy can be administered.
This type of Systemic Chemotherapy, although effective at controlling the cancer, can be toxic to healthy tissues particularly the bone marrow, suppressing the blood cell count, and leaving the patient more vulnerable to serious infections. Hence the blood is very closely monitored throughout.
Checking on the growth of the metastatic centres is usually performed by regular medical check-ups including a watch on the PSA level. When recurrent disease is suspected, further imaging tests will usually be performed to show where these growths are situated and how large they are – hence dictating when Chemotherapy should be applied. The imaging tests might include regular X-rays, CT or MRI scanning, Bone Scan, or PET/CT. The most sensitive of these tests is the PET/CT, which thankfully is becoming more widely available.
In many cases, Stage 4 Prostate Cancer can be viewed and managed as a “chronic” illness, to be kept under close surveillance, and potentially treated by Chemotherapy and hormones through cycles of remission and recurrence. This is a “best case” scenario with Stage 4, and is dependent on the aggressiveness of the cancer.