Abstract
A total of 347 patients with stages A2-C adenocarcinoma of the prostate treated with external beam radiotherapy and with pretreatment and 3-month prostate-specific antigen (PSA) levels were studied to evaluate the potential prognostic significance of the fall in PSA concentration from its baseline (PSAB) to its 3-month (PSA3) level. PSA levels fell in 333 patients (96%). With two exceptions, the patients whose PSA level did not fall had low PSAB and remained without evidence of disease. Since PSA levels fall virtually always, the fact that a fall occurs is of no prognostic value. When the magnitude of the fall relative to baseline was examined, patients with the largest falls had the worst outcomes. This paradoxical result was explained by the relationship between PSAB and PSA3. Regression analysis showed that the fall in PSA level was approximately proportional to the cube root of the baseline value. Thus, patients with high PSAB had high falls, but a high PSAB was an ovewhelming predictor for poor outcome. Hence, PSA fall relative to baseline was not a meaningful prognostic factor. The only factor of prognostic value was the absolute PSA3 value. Patients with PSA3 ≤2 ng/ml fared well at 4 years (freedom from relapse, 91%; incidence of rising PSA profile, 20%); patients with PSA3 > 2, but <-10 ng/ml had an intermediate, individually indeterminate outcome (freedom from relapse, 51%; incidence of rising PSA profile, 58%); patients with PSA3 >10 ng/ml can be said to have failed treatment (freedom from relapse, 50%; incidence of rising PSA profile, 90%). Although this analysis is based on short follow-up, it shows that the PSA value at 3 months after radiation provides a remarkably early assessment of response to treatment and the only patients who can be clearly stated to have responded well to treatment are those whose PSA level falls to ≤ 2 ng/ml. The long-term implications of 3-month PSA values await further follow-up.
| Original language | English |
|---|---|
| Pages (from-to) | 121-127 |
| Number of pages | 7 |
| Journal | Radiotherapy and Oncology |
| Volume | 30 |
| Issue number | 2 |
| DOIs | |
| State | Published - Jan 1 1994 |
| Externally published | Yes |
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Keywords
- Prostate cancer
- Prostate-specific antigen
- Radiation therapy
ASJC Scopus subject areas
- Oncology
- Radiology Nuclear Medicine and imaging
- Urology
Cite this
The serum prostate-specific antigen level three months after radiotherapy for prostate cancer : an early indicator of response to treatment. / Zagars, Gunar K.; Pollack, Alan.
In: Radiotherapy and Oncology, Vol. 30, No. 2, 01.01.1994, p. 121-127.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - The serum prostate-specific antigen level three months after radiotherapy for prostate cancer
T2 - an early indicator of response to treatment
AU - Zagars, Gunar K.
AU - Pollack, Alan
PY - 1994/1/1
Y1 - 1994/1/1
N2 - A total of 347 patients with stages A2-C adenocarcinoma of the prostate treated with external beam radiotherapy and with pretreatment and 3-month prostate-specific antigen (PSA) levels were studied to evaluate the potential prognostic significance of the fall in PSA concentration from its baseline (PSAB) to its 3-month (PSA3) level. PSA levels fell in 333 patients (96%). With two exceptions, the patients whose PSA level did not fall had low PSAB and remained without evidence of disease. Since PSA levels fall virtually always, the fact that a fall occurs is of no prognostic value. When the magnitude of the fall relative to baseline was examined, patients with the largest falls had the worst outcomes. This paradoxical result was explained by the relationship between PSAB and PSA3. Regression analysis showed that the fall in PSA level was approximately proportional to the cube root of the baseline value. Thus, patients with high PSAB had high falls, but a high PSAB was an ovewhelming predictor for poor outcome. Hence, PSA fall relative to baseline was not a meaningful prognostic factor. The only factor of prognostic value was the absolute PSA3 value. Patients with PSA3 ≤2 ng/ml fared well at 4 years (freedom from relapse, 91%; incidence of rising PSA profile, 20%); patients with PSA3 > 2, but <-10 ng/ml had an intermediate, individually indeterminate outcome (freedom from relapse, 51%; incidence of rising PSA profile, 58%); patients with PSA3 >10 ng/ml can be said to have failed treatment (freedom from relapse, 50%; incidence of rising PSA profile, 90%). Although this analysis is based on short follow-up, it shows that the PSA value at 3 months after radiation provides a remarkably early assessment of response to treatment and the only patients who can be clearly stated to have responded well to treatment are those whose PSA level falls to ≤ 2 ng/ml. The long-term implications of 3-month PSA values await further follow-up.
AB - A total of 347 patients with stages A2-C adenocarcinoma of the prostate treated with external beam radiotherapy and with pretreatment and 3-month prostate-specific antigen (PSA) levels were studied to evaluate the potential prognostic significance of the fall in PSA concentration from its baseline (PSAB) to its 3-month (PSA3) level. PSA levels fell in 333 patients (96%). With two exceptions, the patients whose PSA level did not fall had low PSAB and remained without evidence of disease. Since PSA levels fall virtually always, the fact that a fall occurs is of no prognostic value. When the magnitude of the fall relative to baseline was examined, patients with the largest falls had the worst outcomes. This paradoxical result was explained by the relationship between PSAB and PSA3. Regression analysis showed that the fall in PSA level was approximately proportional to the cube root of the baseline value. Thus, patients with high PSAB had high falls, but a high PSAB was an ovewhelming predictor for poor outcome. Hence, PSA fall relative to baseline was not a meaningful prognostic factor. The only factor of prognostic value was the absolute PSA3 value. Patients with PSA3 ≤2 ng/ml fared well at 4 years (freedom from relapse, 91%; incidence of rising PSA profile, 20%); patients with PSA3 > 2, but <-10 ng/ml had an intermediate, individually indeterminate outcome (freedom from relapse, 51%; incidence of rising PSA profile, 58%); patients with PSA3 >10 ng/ml can be said to have failed treatment (freedom from relapse, 50%; incidence of rising PSA profile, 90%). Although this analysis is based on short follow-up, it shows that the PSA value at 3 months after radiation provides a remarkably early assessment of response to treatment and the only patients who can be clearly stated to have responded well to treatment are those whose PSA level falls to ≤ 2 ng/ml. The long-term implications of 3-month PSA values await further follow-up.
KW - Prostate cancer
KW - Prostate-specific antigen
KW - Radiation therapy
UR - http://www.scopus.com/inward/record.url?scp=0028314295&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0028314295&partnerID=8YFLogxK
U2 - 10.1016/0167-8140(94)90040-X
DO - 10.1016/0167-8140(94)90040-X
M3 - Article
C2 - 7514308
AN - SCOPUS:0028314295
VL - 30
SP - 121
EP - 127
JO - Radiotherapy and Oncology
JF - Radiotherapy and Oncology
SN - 0167-8140
IS - 2
ER -