Vijayakumar S, Quadri S F, Sen S, Vaida F, Ignacio L, Weichselbaum R R
Michael Reese/University of Chicago Center for Radiation Therapy, Department of Radiation and Cellular Oncology, University of Chicago, IL, USA.
Int J Radiat Oncol Biol Phys. 1995 Apr 30;32(1):189-95. doi: 10.1016/0360-3016(94)00460-3.
To study the response of nonmalignant prostatic tissue to ionizing irradiation in terms of the resultant changes in serum prostate specific antigen (PSA) levels.
Weekly serum PSA values were determined during radiotherapy (RT) in nine patients ("treatment group") without clinical evidence of prostate cancer (PC), and who received pelvic RT for other indications. Slopes for the rate of change in PSA was determined using model: log PSA = beta 0 + beta 1week + beta 2week2 + error. These results are compared with 17 normal volunteers ("control group") who were not exposed to ionizing irradiation. An attempt is made to compare any similarities and differences in subsets of 64 T1-T4N0M0 PC patients who received pelvic RT.
An elevation in the serum PSA levels were noted in eight of nine patients in the "treatment group" with a median time of 4.2 weeks to reach the maximum serum PSA values. After an initial increase, PSA values declined. In some patients, manifold increase in PSA was noted, for example, from 1.8 to 13.5 ng/ml and 3.3 to 9.8 ng/ml in two patients. The PSA increase ranged from 50-650%. The median slope was 0.601 week-1 (range 0.192-3.045 week-1). No such increases were seen in the "control group" (median slope = 0.03 week-1; range, 0.18-0.13 week-1). When differences between the mean increase/decrease for each week compared to pretreatment values were analyzed, the irradiated group had statistically significant elevations in the PSA for weeks 3 (p = 0.034), 4 (p = 0.035), and 5 (p = 0.024). A similar trend of increasing PSA levels during radiotherapy was noted in prostate cancer patients whose initial PSA values were < or = 20 ng/ml: whereas positive slopes (i.e., increasing PSA levels during radiotherapy course) was seen in 7.1% of those with > 20 ng/ml preradiotherapy PSA values, such trends were seen in 52.7% of those with < or = 20 ng/ml preradiotherapy PSA values.
(a) Incidental exposure of noncancerous prostate to ionizing irradiation appears to lead to an initial elevation followed by a decline in serum PSA. (b) Similar elevations in serum PSA levels are seen in over 50% of prostate cancer patients with < or = 20 ng/ml pretreatment PSA. (c) Acinal cell death and sudden release of PSA into the circulation is the most likely explanation for our observations, although other mechanism cannot be excluded. (d) Our observations have to be considered in modeling PSA kinetics induced by RT and in correlating such kinetics to long-term outcomes. (e) Our findings in the control group indicate that there appears to be no significant variation in serum PSA over many weeks under physiological conditions in normal healthy ambulatory men.
根据血清前列腺特异性抗原（PSA）水平的变化，研究非恶性前列腺组织对电离辐射的反应。
在放疗（RT）期间，对9例无前列腺癌（PC）临床证据且因其他指征接受盆腔放疗的患者（“治疗组”）每周测定血清PSA值。使用模型log PSA = beta 0 + beta 1周 + beta 2周² + 误差来确定PSA变化率的斜率。将这些结果与17名未接受电离辐射的正常志愿者（“对照组”）进行比较。尝试比较64例接受盆腔放疗的T1 - T4N0M0 PC患者亚组中的异同。
“治疗组”9例患者中有8例血清PSA水平升高，达到最大血清PSA值的中位时间为4.2周。初始升高后，PSA值下降。在一些患者中，PSA出现了数倍的升高，例如，两名患者的PSA分别从1.8 ng/ml升至13.5 ng/ml和从3.3 ng/ml升至9.8 ng/ml。PSA升高幅度为50 - 650%。中位斜率为0.601周⁻¹（范围为0.192 - 3.045周⁻¹）。“对照组”未出现此类升高（中位斜率 = 0.03周⁻¹；范围为0.18 - 0.13周⁻¹）。当分析与治疗前值相比每周平均升高/降低的差异时，放疗组在第3周（p = 0.034）、第4周（p = 0.035）和第5周（p = 0.024）的PSA有统计学显著升高。在初始PSA值≤20 ng/ml的前列腺癌患者中，放疗期间也观察到类似的PSA水平升高趋势：放疗前PSA值>20 ng/ml的患者中，7.1%出现正斜率（即放疗过程中PSA水平升高），而放疗前PSA值≤20 ng/ml的患者中，52.7%出现此类趋势。
（a）非癌性前列腺意外暴露于电离辐射似乎导致血清PSA先升高后下降。（b）超过50%的治疗前PSA≤２０ｎｇ/ml的前列腺癌患者血清PSA水平出现类似升高。（c）腺泡细胞死亡以及PSA突然释放到循环中是对我们观察结果最可能的解释，尽管不能排除其他机制。（d）在建立放疗诱导的PSA动力学模型以及将此类动力学与长期结果相关联时，必须考虑我们的观察结果。（e）我们在对照组中的发现表明，在正常健康活动男性的生理条件下，数周内血清PSA似乎没有显著变化。
