Skip to content

Tag: prostate specific antigen (PSA)

Published on Leave a comment on Treat Localized Prostate Cancer Or Not?

This is similar to what Dr. Gilbert Welch and others have been saying for a while - that studies show much cancer screening leads to overdiagnosis and overtreatment with no real differences in rates of mortality (death). Which was the whole point of cancer screening - to catch cancers early and so reduce rates of death. (For more on this topic see here, here, here, and here.) There are harms from overtreatment (unnecessary treatment), and with prostate cancer treatment there can be adverse effects on sexual (erectile dysfunction) , urinary, or bowel function, and sometimes even death from surgery. Remember that many prostate cancers are "indolent" or very slow growing, and may remain asymptomatic throughout the man's lifetime. Currently the U.S. Preventive Services Task Force (USPSTF) recommends against prostate-specific antigen (PSA)-based screening for prostate cancer for these reasons.

This study in the New England Journal of Medicine reported on men diagnosed with prostate cancer, with the men then assigned to either monitoring or treatment (surgery or radiation), and then followed for 10 years. Much to the researchers' surprise, the survival rates from prostate cancer were equally high in all the groups - 99%. Now, as the researchers themselves point out - the groups of men need to be followed for more years. Will there be differences after 15 or 20 years? Also, if there is prostate cancer progression in the monitored group (and more men did have disease progression in this group after 10 years, even though the numbers were low), can it still be treated just as successfully? More studies are needed. Note that there was cancer progression among some men even in both treatment groups.

Other important prostate cancer studies are also needed. Are there differences among those men for whom cancer progresses and for those that it doesn't? Does intense exercise make a difference (as some think)? Dietary differences, such as a plant based diet? Body fat or weight? From Science Xpress: Treat or monitor early prostate cancer? 10-yr survival same

Men with early prostate cancer who choose to closely monitor their disease are just as likely to survive at least 10 years as those who have surgery or radiation, finds a major study that directly tested and compared these options. Survival from prostate cancer was so high—99 percent, regardless of which approach men had—that the results call into question not only what treatment is best but also whether any treatment at all is needed for early-stage cases. And that in turn adds to concern about screening with PSA blood tests, because screening is worthwhile only if finding cancer earlier saves lives.

The study involved more than 82,000 men in the United Kingdom, aged 50 to 69, who had tests for PSA, or prostate specific antigen. High levels can signal prostate cancer but also may signal more harmless conditions, including natural enlargement that occurs with age. Researchers focused on the men diagnosed with early prostate cancer, where the disease is small and confined to the prostate. Of those men, 1,643 agreed to be randomly assigned to get surgery, radiation or active monitoring. That involves blood tests every three to six months, counseling, and consideration of treatment only if signs suggested worsening disease.

A decade later, researchers found no difference among the groups in rates of death from prostate cancer or other causes. More men being monitored saw their cancers worsen—112 versus 46 given surgery and 46 given radiation. But radiation and surgery brought more side effects, especially urinary, bowel or sexual problems....PSA testing remains popular in the U.S. even after a government task force recommended against it, saying it does more harm than good by leading to false alarms and overtreatment of many cancers that would never threaten a man's life. In Europe, prostate cancer screening is far less common.

From the original study in the The New England Journal of Medicine: 10-Year Outcomes after Monitoring, Surgery, or Radiotherapy for Localized Prostate Cancer

The comparative effectiveness of treatments for prostate cancer that is detected by prostate-specific antigen (PSA) testing remains uncertain.  In the United States alone, an estimated 180,890 cases will be diagnosed in 2016, and 26,120 men will die from the disease.1 The widespread use of PSA testing has resulted in a dramatic increase in the diagnosis and treatment of prostate cancer, but many men do not benefit from intervention because the disease is either indolent or disseminated at diagnosis. Prostate cancer often progresses slowly, and many men die of competing causes. In addition, interventions for prostate cancer can have adverse effects on sexual, urinary, or bowel function. Two treatment trials have evaluated the effectiveness of treatment, but they did not compare the most common contemporary methods: surgery, radiotherapy, and monitoring or surveillance

We compared active monitoring, radical prostatectomy, and external-beam radiotherapy for the treatment of clinically localized prostate cancer. Between 1999 and 2009, a total of 82,429 men 50 to 69 years of age received a PSA test; 2664 received a diagnosis of localized prostate cancer, and 1643 agreed to undergo randomization to active monitoring (545 men), surgery (553), or radiotherapy (545). The primary outcome was prostate-cancer mortality at a median of 10 years of follow-up. Secondary outcomes included the rates of disease progression, metastases, and all-cause deaths.

There were 17 prostate-cancer–specific deaths overall: 8 in the active-monitoring group (1.5 deaths per 1000 person-years; 95% confidence interval [CI], 0.7 to 3.0), 5 in the surgery group (0.9 per 1000 person-years; 95% CI, 0.4 to 2.2), and 4 in the radiotherapy group (0.7 per 1000 person-years; 95% CI, 0.3 to 2.0); the difference among the groups was not significant (P=0.48 for the overall comparison). In addition, no significant difference was seen among the groups in the number of deaths from any cause (169 deaths overall; P=0.87 for the comparison among the three groups). Metastases developed in more men in the active-monitoring group (33 men; 6.3 events per 1000 person-years; 95% CI, 4.5 to 8.8) than in the surgery group (13 men; 2.4 per 1000 person-years; 95% CI, 1.4 to 4.2) or the radiotherapy group (16 men; 3.0 per 1000 person-years....). Higher rates of disease progression were seen in the active-monitoring group (112 men; 22.9 events per 1000 person-years; 95% CI, 19.0 to 27.5) than in the surgery group (46 men; 8.9 events per 1000 person-years; 95% CI, 6.7 to 11.9) or the radiotherapy group (46 men; 9.0 events per 1000 person-years....).

At a median of 10 years, prostate-cancer–specific mortality was low irrespective of the treatment assigned, with no significant difference among treatments. Surgery and radiotherapy were associated with lower incidences of disease progression and metastases than was active monitoring.

Published on Leave a comment on Report Says Mammograms Haven’t Reduced Rate Of Metastatic Cancer

A report by 3 prominent specialists (including Gilbert Welch - who has been discussed in earlier posts) about trends in metastatic breast and prostate cancer came out today in the New England Journal of Medicine. The biggest finding was that mammograms have not cut the rate of metastatic breast cancer. Mammography screening is based on the hope that cancer that is detected in an early, localized phase can then be treated more easily and that it would reduce the numbers of metastastic cancers (that spread to lymph nodes and to more distant organs) that eventually kill. However, this has not happened.The incidence of metastatic breast cancer has been stable since 1975, and the average age of diagnosis among women older than 40 is still 63.7 years . The authors theorize that "breast cancer is a systemic disease by the time it's detectable". From Medical Xpress:

Study: Mammograms haven't cut rate of advanced breast cancer

A new report raises fresh questions about the value of mammograms. The rate of cancers that have already spread far beyond the breast when they are discovered has stayed stable for decades, suggesting that screening and early detection are not preventing the most dangerous forms of the disease. The report, in Thursday's New England Journal of Medicine, is by three prominent cancer specialists and is based on federal statistics going back to the 1970s.

"We're undergoing what I think for the public is a very confusing debate" about screening, but it's really "a course correction" prompted by more awareness of its risks and benefits to various groups of women, said Dr. H. Gilbert Welch, a health policy expert at Dartmouth Medical School. "All they heard for years was, 'there are only benefits.'" He is the lead author of the report, co-written with Dr. David Gorski of Wayne State University School of Medicine in Detroit and Dr. Peter Albertsen of the University of Connecticut Health Center in Farmington.

"Screening offers hope that cancer can be detected in an early, localized phase when it's more amenable to treatment," they write, but that assumes that cancer starts in one place, grows and then spreads. If that was always true, screening would reduce the rate of advanced cancers. And that has not happened. The rate of breast cancers detected at an advanced stage has been stable since 1975, despite wide use of mammography since the 1980s. The average age of women diagnosed with cancer also has remained around 63, another sign cancers are not being found sooner.

The trends suggest that some breast cancers are already "systemic" or widely spread from the start, and that finding them sooner has limited impact. "Screening mammography has been unable to identify those bad cancers, destined to become metastatic, at an earlier stage. That doesn't say mammography doesn't help less aggressive cancers," but those are less likely to prove deadly, Welch said.

Dr. Barnett Kramer, a screening expert at the National Cancer Institute, said the report shows the limitations of mammography. "I wouldn't want to say it has had no effect but it certainly has not lived up to the anticipated effect," he said. For every tumor detected early because of mammography, "you would hope to see ... an equal reduction in metastatic disease, and that has not occurred."

The situation is very different with prostate cancer. The rate of advanced cases of that disease has been cut in half since screening with PSA blood tests came into wide use around 1988, and the average age at which men are diagnosed has fallen—from 72 to 70, the authors write. However, this does not prove PSA testing is good. Shifting the stage at which a disease is diagnosed is "only the first step for successful screening," which also has to save lives to be worthwhile, Welch said. "Just because you find something earlier doesn't mean you can change its course."

Again, Kramer agreed. Prostate screening, "when put to a definitive test, did not show a clear reduction in prostate cancer mortality" in large, rigorously done trials, he said. The government task force recommends against PSA testing, and says its risks outweigh its benefits for most men.

"Screening is a close call," Welch said. "My guess is few people are helped" by prostate or breast cancer screening while many are harmed by false alarms that trigger unnecessary tests and treatments, he said.

The original report, which also includes a discussion on prostate cancer and the PSA test, in the New England Journal of Medicine:  Trends in Metastatic Breast and Prostate Cancer — Lessons in Cancer Dynamics

Published on Leave a comment on Nearly 70% of Prostate Cancers Can Just Be Watched?

The issue of overdiagnosis and overtreatment has recently been in the news, especially when discussing breast cancer, prostate cancer, and thyroid cancer. Meaning too much unnecessary treatment with harms, when the best approach would have been to do nothing, as studies have suggested or actually shown. Now here is an article in Medscape suggesting that rather than be quick to operate or treat, the best approach for nearly 70% of prostate cancers may be just "watching".

The U.S. Preventive Task Force, which analyzes the value of screening tests, in May 2012 recommended AGAINST routine prostate-specific antigen (PSA)-based screening for prostate cancer for all age groups. According to them, studies do not show that benefits of routine screening of asymptomatic prostate cancer and the resulting treatment outweigh the harms of treatment (e.g., surgical complications including death from surgery, erectile dysfunction, urinary incontinence, bowel dysfunction, and bladder dysfunction), or that prostate cancer treatment even reduces mortality (deaths).

They point out that: "There is convincing evidence that PSA-based screening programs result in the detection of many cases of asymptomatic prostate cancer. There is also convincing evidence that a substantial percentage of men who have asymptomatic cancer detected by PSA screening have a tumor that either will not progress or will progress so slowly that it would have remained asymptomatic for the man's lifetime. The terms "overdiagnosis" or "pseudo-disease" are used to describe both situations." (NOTE: others have argued against this recommendation)

When reading the full Medscape article, it was pointed out that in the study being discussed, one person who was offered active surveillance but declined and was treated with an immediate radical prostatectomy, still died of metastatic prostate cancer. This was an example of a case where when the disease is truly aggressive, it may have spread "like a bird" throughout the body (in Dr. H. Gilbert Welch's terms in his books Overdiagnosed and Less Medicine, More Health) from the very beginning, and may be unstoppable no matter what is done.

I have also noticed reading other prostate cancer studies that a certain percentage of prostate cancers regress from the point of diagnosis (the PSA test and biopsy). In other words, researchers are finding that cancer can have different paths: regresses, stays the same, grows slowly (and can be treated when symptoms appear), or grows very quickly and is so aggressive and unstoppable that it goes through the body "like a bird". And we don't know which will be the aggressive ones when we first find them, thus the controversies over what to do: screen or not?, and treat or not?  ...continue reading "Nearly 70% of Prostate Cancers Can Just Be Watched?"