Swinging on biases and outcomes
James Fleck, MD, PhD: Anticancerweb 21 (11), 2021
Prostate cancer competes with lung cancer for the leading position in incidence of malignant diseases, in the world. Data from Global Cancer Observatory in 2020 show a crude incidence rate of 36.5 and 36.0 respectively for lung and prostate cancer. The epidemiological signature of prostate cancer in the United States is an exciting issue marked by mixed effects. Taking the year 1975 as a baseline, the incidence of prostate cancer markedly increased, especially around late eighties and early nineties, when the crude incidence rate more than doubled (close to 2.5 times, compared to baseline). The initiation of widespread PSA screening was the main responsible for this peak. During the same period, prostate cancer mortality showed a slightly increase followed by consistent decrease (almost half compared to the baseline). Curiously, incidence of metastatic prostate cancer (m-PC) at the diagnosis showed an expected decrease after initiation of PSA screening, followed, more recently, by a paradoxical increase. However, the recent increase in m-PC diagnosis may not be a real paradox, as long as it was associated to an issued PSA screening grade D recommendation by the US Preventive Service Task Force (USPSTF), issued in 2012. This recommendation was associated to an additional markedly decrease in prostate cancer incidence, but also to a slightly increase in the diagnosis of metastatic disease. A grade D means that USPSTF was against PSA screening method, arguing that there was moderate or high certainty that the method has no net benefit or that the harms outweigh the benefits. Fortunately, in 2018 the USPSTF issued a new grade C recommendation, stating that prostate cancer screening should be an individualized decision based on personal preference, when weighting the benefits and harms of the method (shared-decision making). Further analysis of the prostate cancer epidemiological signature will assess the impact of this most recent USPSTF policy review.
References:
1. Global Cancer Observatory: International Agency for Research on Cancer: World Health Organization, 2020
2. H. Gilbert Welch, Barnett S. Kramer and William C. Black: Epidemiologic Signatures in Cancer, N Engl J Med 381 (14), October 3rd, 2019
3. Centers for Disease Control and Prevention: Morbidity and Mortality Weekly Report 69 (41), October 16th, 2020
4. Jason M. Broderick: Incidence of Metastatic Prostate Cancer on the Rise, Oncology 460, November 2020
5. Virginia A. Moyer: Screening for Prostate Cancer: U.S. Preventive Services Task Force Recommendation Statement, Ann Intern Med 157:120-134, 2012
6. Photo by Colton Sturgeon on Unsplash
Screening for prostate cancer has made great strides in recent years. Even prostate cancer having an incidence close to lung the mortality difference is high due to the difference in treatment and screening. A new grade C recommendation from the US Preventive Service Task Force increased patient independence and joint decision with the doctor. Due to the change in survival time depending on the stage of prostate cancer early diagnosis may be essential
This article is amazing and show how science is constantly evolving !! While once believed to revolutionize the diagnosis of this disease, today the PSA is frequently charged with leading to unnecessary treatment as well as causing unnecessary anxiety. The PSA is a marker of prostate bulk and size, but it's highly expressed in benign prostate disease as well as cancer so in that context it's not a specific marker.
The screening of prostate cancer is a tricky matter. Although, the screenig can detect cancer in its inicial state it also can reveal a false positive witch can lead to invasive procidures such as biopsy and also unecessary treatments.
Fortunately, shared decisions between patient and doctor are becoming more and more common. Each patient perceives life in a unique way, and this is also reflected in how he sees the possibility of having prostate cancer. It is important to instruct the patient with the necessary information about the screening process and let him choose whether to do it or not.
In the last 40-50 years, we observed a significant growth in prostate cancer screening. During this time we can notice how such screening has evolved. Some years ago there was a widespread use of PSA, and now what we see is a reduction in the use of this marker, since there has been questions to its efficacy in actually decreasing prostate cancer mortality and other outcomes.
One of the problems in screening for prostate cancer is that an elevated PSA does not necessarily indicate a tumor alteration. However, many times this test precedes even the rectal examination, and the patient is referred for biopsy, thus increasing the number of false-positive cases. Much of this is the result of marketing issues where doctors tend to reduce the time of consultations to increase financial gain, and end up requesting more tests than normal to assess the complete state of the patient.
Considering PSA elevations doesn't always mean prostatic cancer (it can also happen in benign prostatic hyperplasia, for instance), it can be hard to decide when to dose PSA. Fortunately, discussion between physician and patient is increasing over time and this decision can be made with more transparency. In this discussion it is vital to consider that early diagnosis of prostate cancer and, most importantly, metastatic prostate cancer, means a much higher rate of cure, and that can be accomplished by dosing PSA and, if the results are above normal range, performing further investigation.
The complexity of screening for prostate cancer requires the physician to have a keen eye on the issue, which will define actions to be taken or not, and this act must be shared with the patient so that together they obtain the best form of treatment.
Please login to write your comment.
If you do not have an account at Anticancerweb Portal, register now.