DECK VIEW FROM TI KANOT BY CHRIS DOYLE
Cruisers’ Health: A Message for the Men

It has become noticeable to me that I am not the only sailor getting older. Many other Caribbean cruisers look to be not far behind and I see very few 20- and 30-year olds hanging out on boats in the islands; we are an aging demographic. So, before I start my series “marinized-amphibious wheelchairs” I thought I’d write about the PSA test. If you are a woman or your first reaction is “What the hell is that?” stop reading and forget you ever heard the words mentioned. I’m talking to my fellow “boomer cruiser” guys here. My interest in the subject stems from recent personal experience.
All cruisers have our routine maintenance “to do” lists, for ourselves as well as for our boats. A regular PSA test might well be on your list. But right now, many long-accepted beliefs are being questioned in the light of new data, which you might not be aware of if you’ve been reading more engine manuals or cruising guides than medical journals.

We all know that cancer is something we really do not want. The conventional wisdom is that cancer is best caught early — find it, cut it out, use chemotherapy and radiation where necessary, and move on. In many cases this still applies; I would certainly want melanoma and many other cancers treated that way.
Prostate cancer, however, may be different. It can be aggressive and kill people quickly, but more often it is a slow-growing cancer and many men will die with prostate cancer, not of it. Depending on the study you look at, if you have prostate cancer, your chances of dying from it, as opposed to something else, is between ten and 35 percent. On the other hand, it is a leading cause of death: about 3.3 percent of men die from it. At the same time, autopsy studies* show that a third of men aged 40 to 60 have prostate cancer, which increases to 75 percent by the age of 75, and most died of something else. As you read on you might note that this is a much higher rate than that detected by biopsy. I assume this is because in biopsies surgeons take samples and can easily miss cancers, whereas in an autopsy you can examine the whole prostate. 

The PSA test is specific to the prostate and high PSA levels can be a sign of cancer, but high PSA levels can also result from infections, calcification and other prostate problems. Furthermore, the PSA test almost equally fails to detect cancer. The chart shown is from the Hopkins Center; it gives no clue as to the age of the subjects and the picture would surely change with age. According to this chart, eight out of a hundred people would have high PSA levels and three of those eight would have cancer. Of the remaining 92, two will have cancer that has not been detected. So the test is able to detect over half the cancers in the group, which is not all bad. Unfortunately, it will also lead to unnecessary invasive biopsies in five out of eight of those with a high PSA. Then again, a biopsy only takes a very small sample of your prostate, so it is quite possible for a cancer to be missed, so to be on the safe side those with high PSA will probably get annual biopsies for some years to come.

However, the PSA does catch over half the cancers and enables quick treatment. Early figures overestimated the success of this approach because of a statistical artifact known as “lead time bias”. I came across this when following one of the US elections where healthcare was an issue. One of the figures put out by people passionately campaigning against any kind of US government healthcare was that in US people diagnosed with cancer survived some years longer than those in other countries with national health care. I thought this a bit strange, so I did some checking on the age at which people died of cancer in several countries and it was about the same. The claim was true but misleading. People do survive longer after diagnosis in the US, not because they were living longer, but because their cancer was diagnosed at an earlier stage. 
There is also a downside to both biopsy and treatment. With biopsy it is relatively minor. According to the Annals of Internal Medicine** about a third will experience anything from bleeding and pain to infection that will demand a follow-up, and one percent will need hospitalization. When cancer is detected, most people want it removed by radiation or surgery. As a result five in a thousand will die within a month of prostate surgery of various complications, between one and seven percent will have serious complications and survive, and 20 to 30 percent will have more minor, but sometimes permanent complications such as urinary incontinence and erectile dysfunction in the case of surgery, and bowel dysfunction in the case of radiation.

All this might be worth it if this saves many lives, but does it? This is a much trickier question because such studies generally run for a long time, usually ten to 20 years, and people are still alive at the end who may yet die of cancer, so the full benefits of early testing may not be showing up.
In the studies that have been done, the results are unimpressive. If groups who had a PSA test are compared with those who did not, almost no studies show a significant change in mortality, though some do show fewer deaths from prostate cancer. At best, we may be saving one cancer death per thousand people screened, while over-treatment will do damage to 30 or 40 per thousand.
To get a clear picture, a study is needed in which patients whose early cancer was detected by PSA are separated into “treatment” and” no treatment” groups, as was done in a recent study published in the New England Journal of Medicine**. Seven hundred and thirty-one men with localized prostate cancer were divided into two randomized groups; in one group the prostate was removed and the others were simply observed. The men were followed from 1994-2002, and the benefits were analyzed in 2010. Their conclusion: “Among men with localized prostate cancer detected during the early era of PSA testing, radical prostatectomy did not significantly reduce all-cause or prostate-cancer caused mortality, as compared with observation, through at least 12 years of follow-up.” (Italics mine.) This is a rather small study; a larger one may show a benefit.
All this has led the US Preventive Services Task Force to conclude, “men deserve to know what the science tells us about PSA screening: there is a very small potential benefit and significant potential harms.”
It should be noted that this conclusion is controversial, both among urologists and patients. If you read blogs on the subject, you will find many stories of men who have had treatment, are happy to be alive, and conclude that treatment has saved their lives. The results of some studies suggest many of those treatments were unnecessary.

Many men die of prostate cancer and it would be a boon if we could detect and effectively treat it. At the present, it can be detected, but doctors are unable to tell which cancers are going to kill. Now, when the prostate is removed in the early stages, there is no clear evidence that this does much good. So if you have no prostate problems or symptoms and are considering the PSA test as a routine measure, you may want to go sailing instead.

* www.nytimes.com/2011/10/07/health/07prostate.html?_r=0
** http://annals.org/article.aspx?articleid=1216568
*** www.nejm.org/doi/full/10.1056/NEJMoa1113162?query=featured_home&

From a sailing family on the south coast of England, Chris Doyle earned a doctorate in psychology before sailing to the Caribbean in 1969 and becoming a resident of Grenada. He is the author of several regional cruising guides. Visit his website at www.sailorsguide.com.