Prostate cancer screening

 

WHY?

According to 2000 statistics, prostate cancer is the most common male cancer (40,000 cases per year), and the second leading cause of cancer death in men (10 000 deaths per year). It occurs mostly beyond 50 years.

Prostate cancer screening

As with any cancer, the discovery of cancer at a very early stage when the disease is likely to be still localized to the prostate, offers the best chance of cure, also thanks to significant progress in the management therapy whose efficiency is now proved.

The advent of prostate-specific marker (but not cancer-specific) was a breakthrough which, in most cases, allows to the diagnosis at a very early time of the natural history of cancer prostate. Before the PSA (prostate specific antigen), 80% of cancers were diagnosed at an advanced or metastatic stage. Since the PSA, the proportion was reversed in favor of localized cancers.

The principle of screening is thus detect cancer in a patient free of symptoms, in order to offer the best chance of cure.

Table I. Probability of cancer according to the different threshold values.

Table I. Probability of cancer according to the different threshold values.

 

HOW?

Screening is based on the combination of DRE and PSA.

PSA dosage can guide the diagnosis to 9 times out of 10 rectal examination remains an essential element: in fact, DRE may be abnormal and indicative of cancer when the PSA is normal.

The higher standard deduction to discuss PSA prostate cancer diagnosis is 3 ng / mL (European Association of Urology).

However, controversy exists on the effective threshold value, knowing that the PSA is also a reflection of benign prostatic hyperplasia and prostatitis associated, elements to be taken into count in the interpretation of the assay.

The free PSA relative to the total PSA as a percentage, refines relative sensitivity of this biomarker, but not really specific, prostatitis or atrophy of the prostate glands which can give without lowering the percentage that there to be associated cancer. The value of this ratio below 10%, however, is clearly suspect.

Similarly, PSA velocity, assessed on the annual successive assays, has an indicative value if the annual increase in the PSA exceeds 0.75 ng / mL / year. However, at age 50, this value can be lowered to 0.40 ng / mL / year.

WHO?

The question, double entry, is essential: it is that of the population at risk definition early onset cancer (hereditary and familial forms) on one hand, and of the risk of overtreatment insignificant cancers low evolving risk in the hope of expected life on the other.

Indeed, the natural history of prostate cancer that between the time of initiation of cancer and eventual death, decades may pass. So everything depends on when the diagnosis is made: if there is “too much” early, at the first appearance of cancer cells, the evolutionary term is far away, and treatment, although effective, would bring the risk of side effects and urinary, sexual or digestive effects encumbering the quality of life of the patient. However, it is difficult today to know actually when the diagnosis is made for an individual patient when prostate biopsies show a very small cancer, to the extent that allows PSA to advance the date of diagnosis of several years. The practitioner must ask the question of an insignificant cancer, for which only one monitoring may be appropriate. Research in this maine do are to specifi c markers that indicate tumor scalability, now under evaluation.

It admits that the diagnosis of prostate cancer in the modern context of screening is most often in a window where the disease is significant and localized to the prostate gland, and the risk of an evolution beyond therapeutic resources there after 10 years of hindsight, term before which all treatments whatsoever, will be equivalent.

Morbidity risk and cost, broadly, a cancer treatment is not justified when there are other possible causes of death that prostate cancer. For example, it is assumed that 100 years, virtually all men are carrying a prostate cancer, but only 3% may die, whereas at 50 years the risk is 75 %.

This is why it is customary to begin screening at age 50, and not consider it after 75 years. This limit “maximum” of 75 years should not be absolute, date of birth is an approximate reflection of the general condition and life expectancy.It is likely that this limit will evolve over time given the anticipated increase in life expectancy at the rate of one year every 4 years. Today, at 75, the average life expectancy is 14.8 years.

Special population is that of family and inherited forms that represent 5-25% of cases of prostate cancer.

Hereditary forms are defined as achieving at least 3 cases of prostate cancer identified in 1st degree relatives, 3 cases of prostate cancer over 3 generations in the same family branch (paternal or maternal), or only 2 cases but early onset before 55 years. They represent 5 to 10% of prostate cancers. The risk of prostate cancer is multiplied by a factor of 10 compared to the sporadic forms.

Family forms, do not meet the criteria for hereditary forms account for 5-25% of prostate cancers, and the risk of prostate cancer is multiplied by 3.5.

The appearance of prostate cancer in these families is earlier, 5 to 10 years earlier than in sporadic cases. This justifies in this case offered screening from 40 years.

RECOMMENDATIONS:

The recommendations of the urological community (French Association of Urology) are proposing individual screening of prostate cancer in men between 50 and 75 years and from 40 years in case of hereditary or familial forms. Screening includes the DRE and PSA testing. The rate of detection is then adjusted based on the results, either annual or biennial or triennial.

This individual screening can only be conceived in a patient informed of the consequences in terms of diagnostic, therapeutic and side effects of any treatment.

CONCLUSIONS:

Beyond the controversy over oversensing and overtreatment, now screening can detect a majority of prostate cancers at a stage of the disease where the probability of cure is very strong. This strategy of effective screening against a common disease responsible for a significant number of deaths, however, has a cost, individually term patients (anxiety, repeated examinations, potential impact of treatment on quality of life) and in terms of health economics (repeat examinations, treatment and follow-up costs). Must therefore be adjusted individually screening strategy based on the PSA test and DRE, in order not only to offer the patients at risk, both because of their family history than their age group and according to life expectancy conditioned by comorbidity.

loading...
«
»

Share This Post

Related Articles

Powered by WordPress · Designed by Theme Junkie