In my last post, I discussed lymph node dissection for men undergoing prostatectomy. Specifically, I focused on who does and does not need a lymph node dissection based on the risk of lymph node involvement by prostate cancer. But what happens when prostate cancer is actually identified in the lymph nodes? In the past, managing men with lymph node positive prostate cancer was not very complicated. Most men were monitored until symptomatic spread of the cancer was noted. After symptoms of metastatic disease emerged, palliative therapy with hormones was initiated. The prognosis was always poor. Today, however, the situation is quite different. First, the prognosis is not the same for all men with lymph node positive disease but, rather, varies with the extent of lymph node involvement. Also, therapy is usually initiated very soon after lymph node disease is diagnosed. Finally, different treatment modalities are being implemented beyond just hormonal therapy. In this post, I will describe these new approaches to treating men with prostate cancer in the lymph nodes.
Not All Lymph Node Positive Prostate Cancer Is The Same
When I was training to be an urologist, all men with prostate cancer found in the lymph nodes were lumped into one category. These men were generally given a relatively poor prognosis with a 10 year survival rate ranging from 50-80% depending on whether or not they received hormonal therapy. Recently, however, studies have demonstrated that not all lymph node disease is the same. Men with greater than 2 lymph nodes involved by prostate cancer, for example, have been shown to have more than twice the likelihood of dying from prostate cancer as compared to those men with 2 or fewer positive lymph nodes. After 10 years of follow up, the cancer-specific survival rates (chances of surviving prostate cancer) for these two groups were reported to be 33% and 79%, respectively. Similar differences were noted based on the density of positive lymph nodes. One study, for example, compared the outcomes of men in whom less than 20% of the lymph nodes removed (during a dissection) were found to harbor cancer with those of men in whom greater than or equal to 20% of the lymph nodes removed were cancerous. The study reported that those men with the lower percentage of positive lymph nodes (<20%) enjoyed a 72% chance of living free of metastatic disease after 10 years as compared to only 47% of men with the greater density of positive lymph nodes.
When Should You Start Treatment For Lymph Node Positive Prostate Cancer?
When prostate cancer invades the lymph nodes, it is considered to be metastatic. As a result, as I mentioned previously, treatment for men with lymph node positive disease in the past was often delayed until symptoms were noted. The reasoning for this treatment approach was that, because the cancer is already metastatic and hormonal therapy is palliative as opposed to curative, there is no compelling reason to start treatment right away. After all, what is the rush in treating a cancer that you cannot cure, right? In 1999, however, a study was published in the New England Journal of Medicine, which completely refuted this line of thinking. The study evaluated a group of about 100 men diagnosed with lymph node positive prostate cancer. About half of these men received hormonal therapy immediately after diagnosis, while the other half did not receive treatment until they developed symptomatic metastatases. The study reported that after 7 years, 85% of men undergoing immediate hormonal therapy were alive as opposed to only 64% of men receiving delayed therapy. This study led to a paradigm shift in treatment. Since that time, most men with positive lymph nodes will undergo immediate hormonal therapy. Interestingly, however, the recent data suggesting significantly better prognoses for men with a small number of positive lymph nodes has led many experts to rethink the need for immediate hormonal therapy in all men. Some have argued that men with minimal lymph node spread may be better served with observation rather than immediate hormonal therapy, particularly in the context of the side effects and dangers of hormonal therapy. Unfortunately, no good data yet exists to support or refute this approach.
Is Hormonal Therapy The Only Option For Managing Lymph Node Disease?
Until recently, the answer was a resounding yes. As I mentioned above, lymph node involvement by prostate cancer has always been considered to be metastatic disease. As such, it has not been considered curable and any treatment has been considered palliative. The mainstay of treatment for metastatic disease has been hormonal therapy, which works to prevent the prostate cancer from spreading further by restricting the fuel for its growth, the male hormone Testosterone.
Recently, however, studies out of Europe have demonstrated that, when added in combination with hormonal therapy, radiation therapy can substantially increase survival in men with lymph node positive disease. A study published just this year, for example, evaluated approximately 360 men with prostate cancer found in their lymph nodes. Of these men, 117 underwent a combination of hormonal therapy and radiation while 247 underwent hormonal therapy alone. The study reported that , after 10 years of follow up, men undergoing the combination therapy enjoyed a cancer specific survival rate of 86% versus only 70% for those men undergoing hormonal therapy alone. Similarly, the overall survival rate of men undergoing the combination therapy was also higher at 10 years as compared to those undergoing hormonal therapy alone (74% versus 55%, respectively). I should stress that the results of this study, while impressive, are by no means definitive and have not yet changed the standard treatment protocol for men with lymph node positive disease. Nonetheless, the data provides food for thought and a topic for discussion between men with lymph node positive prostate cancer and their urologists/oncologists.
Take Home Message
The treatment of men with prostate cancer found in their lymph nodes has undergone significant changes. Lymph node positive disease is no longer one entity but, rather, a spectrum of diseases with varying severities and prognoses depending on the number of positive lymph nodes. While considered metastatic disease, lymph node positive prostate cancer should still be managed early as such expedient treatment has been demonstrated to improve survival. Similarly, early data seems to support the combination of radiation with hormonal therapy in order to optimize survival outcomes for men with lymph node positive prostate cancer. As always, men should thoroughly discuss these and other issues pertaining to the management of prostate cancer with an urologist and/or oncologist prior to making any decisions about their care.
