Introduction
Prostate cancer is synonymous with prostate, a gland found in the human reproductive system. The cancer grows slowly, but some types are very aggressive. The cancerous cells normally spread from the prostate to the other body parts like the lymph nodes. This article intends to review Carter et al’s work on detection of life threatening prostate-PSA velocity (Huggins 210).
The Observations
Carter et al show that in unselected cohort of men that were enrolled in BLSA, the PSA velocity facilitate access to information early in the disease course related to chances of dying of prostrate cancer. Carter et al study shows that PSA velocity can be used in identification of men with prostrate cancer at a time when either surgery or radiation can be used to contain the disease. They suggest that men with low PSA velocity should be major targets of observation. The study further show that the association of prostate cancer with PSA velocity does not differ between pre-PSA and PSA eras. Moreover, there is no statistically significant relationship between PSA velocity and the date when prostrate cancer is diagnosed. Carter et al findings differ with those of D’Amico et al in that D’Amico et al showed that a high PSA velocity prior to diagnosis and surgery was correlated to increased risk of harboring prostrate cancer that cannot be treated by surgical intervention alone, a thing which Carter et al’s study differ with on grounds that their study show that values above a lower threshold of PSA velocity are prompted by presence of life threatening disease when prospects of getting cure may be there because PSA levels at PSA velocity determination were in a range when men had curable diseases (Carter 1523). Moreover, the PSA velocity in Carter et al study was lower than that of D’Amico (0.35 against 2.0). The difference is attributed to direct increase of PSA velocity relative to PSA level. The implications of Carter et al study included use of single PSA value as an indication for biopsy for men. This approach can detect unimportant cancers or miss important cancers especially if the value is lowered for all men. Low PSA levels would imply that enlargement of prostrate cancer is absent. Carter et al further advances that not all men in BLSA had their serum available for PSA testing and that precise estimate of risk of death from prostrate cancer from this study was small.
The Formulated Hypothesis
Prostrate specific velocity can be an important indicator of prostrate cancer.
What the Testable Prediction of the Articles Were
Evaluation of Prostrate Specific Antigen velocity and survival.
The Experiments used by Researchers
Carter et al study subjects participated in the BLSA a study instituted by National Institute of Aging. A total of 1806 males participated. The subjects underwent medical, physical, and neuropsychological examination after every 2 years. Participants signed a consent form before taking part in the study. At each evaluation, PSA measurements and digital rectal examination were done. Subjects with PSA levels higher than 4.0ng/gmL were subjected to transrectal ultrasound directed prostrate biopsy. Frozen sera samples stored at -70oC were used to measure PSA levels. Standard monoclonal immunoradiometric assay was used to perform all PSA measurements. Men totaling 38 with diagnosis of prostrate cancer with no PSA data before their diagnosis; 80 who had simple prostatectomy with no PSA data before surgical intervention; 47 who had administered finasteride; 54 who had unknown cause of death; and those with single PSA value were excluded from the study. After the exclusions, the study had 980 men, 124 of them having had prostate cancer diagnosis, and 856 with unknown prostrate cancer diagnosis. 79 per cent of the men were white; 17 % African American; and 4% Asians and other ethnic groups. Cause of death for subjects was determined from BLSA death file. Deceased BLSA subjects’ cause of death was arrived at after 3 physician’s unanimous agreement supported by autopsy report and medical records. Participants whose prostrate cancer was detected by the use of autopsy were categorized in group of those without cancer. Carter et al used Cox proportional hazards regression in evaluation of associations between PSA level and PSA velocity, participant’s age at diagnosis, date when diagnosis was undertaken, and death caused by prostrate cancer.
Conclusions that were Drawn from the Experiments
Carter et al study assert that PSA velocity can be used in identifying men with chronic prostrate cancer at a time when the individuals PSA levels have correlation with the presence of curable disease. Level of prostrate specific antigen in the serum is used to screen for prostrate cancer. Clinicians are unanimous that PSA screening detects early stage cancers. Controversy still looms on the threshold value at which prostrate biopsy should be recommended. A section of clinicians have accepted a threshold of 4.0ng/mL as a limit for recommending prostrate cancer biopsy. Some urologist have endorsed the use of a threshold of 4.0ng/mL but some are still concerned that lower thresholds risk leading to further increases in prostrate cancer over diagnosis and over treatment.
Works Cited
Carter Ballentine, Luigi Ferrucci, Kettermann Anna, Patricia Landis, Wright James, Epstein Jonathan, Trock Bruce and Metter Jeffrey. Detection of Life-Threatening Prostate Cancer with Prostate-Specific Antigen Velocity during a Window of Curability. J Natl Cancer Inst. 2006 November 1; 98.21 (2OO6): 1521–1527.
Huggins Charles, Steven, and Hodges. “Studies on prostatic cancer”. Arch. Surg. 43 (1941): 209–223.
Carter et al Fig. 1.
Average prostate-specific antigen (PSA) levels in ng/mL as a function of years before diagnosis (Prostate cancer) or last visit (no prostate cancer).
