Tan Yu Guang, Lau Kam On Weber, Huang Hong Hong, Tan Wee Kiat Terence
Department of Urology, Singapore General Hospital, Singapore.
Department of Radiotherapy, National Cancer Centre Singapore, Singapore.
Asian J Urol. 2016 Apr;3(2):59-63. doi: 10.1016/j.ajur.2015.12.001. Epub 2016 Jan 13.
Serum prostate specific antigen (PSA) is commonly used to evaluate treatment response after definitive radiation therapy (RT). However, PSA levels can temporarily rise without a clear reason, termed "PSA bounce", and often engender great anxiety for both patients and physicians. The present study aimed to determine the prevalence and factors that predict "PSA bounce" after intensity-modulated radiation therapy (IMRT), and the relevance to biochemical failure and cancer recurrence in an Asian population.
We retrospectively reviewed 206 patients who received IMRT for prostate cancer from 2004 to 2012 in the National Cancer Centre Singapore. These patients were followed up with regular PSA monitoring. We defined "PSA bounce" as a rise of 0.1 ng/mL, followed by two consecutive falls. Patients with biochemical failure (PSA nadir + 2 ng/mL) were further evaluated for cancer recurrence.
Sixty-one patients (29.6%) experienced "PSA bounce", at a median time of 16 months and lasted for 12 months. Age remained the most consistent predictor of the incidence, duration and extent of "PSA bounce". Other contributory factors included baseline PSA, Gleason score and PSA nadir. Hormonal therapy and prostate volume did not affect this phenomenon. Sixteen patients (7.8%) developed biochemical recurrence, at median time of 32 months, of which 11 were confirmed to have metastatic disease. The median follow-up time was 71 months.
A younger age predicts PSA bounce incidence, duration and magnitude. The extent of bounce appears to be lower in Asian population. The interval to occurrence and extent of PSA elevation separates PSA bounce from disease recurrence.
血清前列腺特异性抗原（PSA）常用于评估根治性放射治疗（RT）后的治疗反应。然而，PSA水平可在无明确原因的情况下暂时升高，即所谓的“PSA反弹”，这常常给患者和医生带来极大的焦虑。本研究旨在确定亚洲人群中调强放射治疗（IMRT）后“PSA反弹”的发生率及预测因素，以及其与生化失败和癌症复发的相关性。
我们回顾性分析了2004年至2012年在新加坡国立癌症中心接受IMRT治疗前列腺癌的206例患者。这些患者接受定期PSA监测随访。我们将“PSA反弹”定义为PSA升高0.1 ng/mL，随后连续两次下降。对发生生化失败（PSA最低点+2 ng/mL）的患者进一步评估癌症复发情况。
61例患者（29.6%）经历了“PSA反弹”，中位时间为16个月，持续12个月。年龄仍然是“PSA反弹”发生率、持续时间和程度最一致的预测因素。其他促成因素包括基线PSA、Gleason评分和PSA最低点。激素治疗和前列腺体积不影响这一现象。16例患者（7.8%）发生生化复发，中位时间为32个月，其中11例确诊有转移疾病。中位随访时间为71个月。
较年轻的年龄可预测PSA反弹的发生率、持续时间和幅度。亚洲人群中反弹程度似乎较低。PSA升高的发生间隔和程度将PSA反弹与疾病复发区分开来。
