Treatment of PSA-Relapsed Prostate Cancer

Even though PSA usage has been questioned for screening, it's considered the “gold standard” for detecting cancer recurrence.  However, not all relapses are serious enough to require treatment. The difference between a low-grade recurrence and a high-grade recurrence is heavily influenced by the rate of cancer growth, which is signaled by the PSA doubling time.

PSA doubling time correlates with the rate of cancer growth.

When PSA requires more than 12 to 15 months to double, the disease is considered low grade and treatment can usually be withheld. PSA doubling times that fall into the 6 to 12-month range are usually a sign that some sort of treatment will be required. PSA doubling time of less than three months are a sign that the disease is aggressive. Multimodality therapy is probably indicated.

Treatment for men with doubling times in the in-between range, say of 6 to 12-months, can progress down one of two pathways. One alternative is to simply suppress the disease with Lupron, given intermittently. For example, after Lupron is started, PSA usually drops to less than 0.1. Lupron is continued for 8 to 12 months and stopped.  Once the effects wear off and testosterone recovers the PSA will begin to rise. A second cycle of Lupron is restarted when the PSA reaches a certain threshold (usually between 3 and 6).

This constitutes one cycle of therapy. This intermittent approach is quite effective and will keep the PSA in check for an average of 11 years.  The side effects, however, such as tiredness, low sex drive and hot flashes, can be a problem.

The alternative to intermittent Lupron is to make a second run for an out and out cure.

If the PSA level is not too high and if thorough evaluation with scans seem to indicate that the cancer is still localized in prostate gland (after radiation) or in the prostate fossa (after surgery), further local therapy to eradicate the residual disease may be curative. Relapses in the prostate after radiation are usually managed with cryotherapy, which is generally less toxic than surgery. Relapse in the fossa after surgery is managed with radiation.

Choosing between these two different pathways is one of personal preference. Hormone therapy as a first step may be attractive because the side effects are reversible. Treatment can be stopped if the side effects are unpleasant and cryotherapy or radiation can be used as a backup.  Conversely, men who prefer to avoid hormone-related side effects may want to attempt to cure the disease with cryotherapy or radiation. In this scenario, hormone therapy is held in reserve as a backup in case the cryotherapy or radiation is not curative.

Men with PSA doubling times less than 3 months face a significantly more dangerous circumstances.

 In this situation, adopting an aggressive treatment plan with multi-modality therapy aimed at controlling local disease and potential early metastatic disease is probably best. The first step is to use optimal scanning technology.  Presently, F18 PET bone scans and C11 Choline or Acetate PET scans are the most effective methods for detecting small metastases.  Once these scans determine the extent of disease, assuming the number of metastases is relatively limited (say less than a maximum of 5), initial treatment with Lupron and Casodex is initiated and continued for at least a year. A couple of months after starting Lupron, radiation is administered to the known metastatic sites that were detected by scanning. Men who also have residual cancer in the prostate (after radiation) or the fossa (after surgery), can consider adding cryotherapy or radiation, respectively.

In addition to the combination approach outlined in the previous paragraph, recent reports also indicate that the addition of chemotherapy with six cycles of Taxotere is likely to further improve survival.  Also, studies are presently in progress to evaluate the effectiveness of adding more potent hormonal agents such as Zytiga or Xtandi to standard Lupron and Casodex therapy.

Continue Reading