PSA bounce after permanent implant prostate brachytherapy may mimic a biochemical failure: A study of 295 patients with a minimum 3-year followup

Prostate-Specific Antigen Bounce after 125I Brachytherapy Using Stranded Seeds with Intraoperative Optimization for Prostate Cancer

Prostate-specific antigen (PSA) bounce is common in patients undergoing 125I brachytherapy (BT), and our study investigated its clinical features. A total of 100 patients who underwent BT were analyzed. PSA bounce and large bounce were defined as an increase of ≥0.2 and ≥2.0 ng/mL above the initial PSA nadir, respectively, with a subsequent decline without treatment. Biochemical failure was defined using the Phoenix definition (nadir +2 ng/mL), except for a large bounce. With a median follow-up of 49 months, 45% and 7% of the patients experienced bounce and large bounce, respectively. The median time to bounce was 24 months, and the median PSA value at the bounce spike was 1.62 ng/mL, a median raise of 0.44 ng/mL compared to the pre-bounce nadir. The median time to bounce recovery was 4 months. The post-bounce nadir was obtained at a median of 36 months after low-dose-rate BT. On univariate analysis, age, the PSA nadir value at 2 years, and prostate volume were significant factors for PSA bounce. The PSA nadir value at 2 years remained significant in multivariate analysis. We should carefully monitor young patients with high prostate volume having a >0.5 PSA nadir value at 2 years for PSA bounce.

Time to PSA rise differentiates the PSA bounce after HDR and LDR brachytherapy of prostate cancer

Purpose

To investigate the differences in prostate-specific antigen (PSA) bounce (PB) after high-dose-rate (HDR-BT) or low-dose-rate (LDR-BT) brachytherapy alone in prostate cancer patients.

Materials and methods

Ninety-four patients with localized prostate cancer (T1-T2cN0), age ranged 50-81 years, were treated with brachytherapy alone between 2008 and 2010. Patients were diagnosed with adenocarcinoma, Gleason score ≤ 7. The LDR-BT total dose was 144-145 Gy, in HDR-BT - 3 fractions of 10.5 or 15 Gy. The initial PSA level (iPSA) was assessed before treatment, then PSA was rated every 3 months over the first 2 years, and every 6 months during the next 3 years. Median follow-up was 3.0 years.

Results

Mean iPSA was 7.8 ng/ml. In 58 cases, PSA decreased gradually without PB or biochemical failure (BF). In 24% of patients, PB was observed. In 23 cases (24%), PB was observed using 0.2 ng/ml definition; in 10 cases (11%), BF was diagnosed using nadir + 2 ng/ml definition. The HDR-BT and LDR-BT techniques were not associated with higher level of PB (26 vs. 22%, p = 0.497). Time to the first PSA rise finished with PB was significantly shorter after HDR-BT then after LDR-BT (median, 10.5 vs. 18.0 months) during follow-up. Predictors for PB were observed only after HDR-BT. Androgen deprivation therapy (ADT) and higher Gleason score decreased the risk of PB (HR = 0.11, p = 0.03; HR = 0.51, p = 0.01). The higher PSA nadir and longer time to PSA nadir increased the risk of PB (HR 3.46, p = 0.02; HR 1.04, p = 0.04). There was no predictors for PB after LDR-BT.

Conclusions

HDR-BT and LDR-BT for low and intermediate risk prostate cancer had similar PB rate. The PB occurred earlier after HDR-BT than after LDR-BT. ADT and higher Gleason score decreased, and higher PSA nadir and longer time to PSA nadir increased the risk of PB after HDR-BT.

Assessment of lower urinary symptom flare with overactive bladder symptom score and International Prostate Symptom Score in patients treated with iodine-125 implant brachytherapy: long-term follow-up experience at a single institute

Background

The aim of this study was to evaluate the combined use of the overactive bladder symptom score (OABSS) and International Prostate Symptom Score (IPSS) as an assessment tool for urinary symptom flare after iodine-125 (¹²⁵I) implant brachytherapy. The association between urinary symptom flare and prostate-specific antigen (PSA) bounce was investigated.

Methods

Changes in the IPSS and OABSS were prospectively recorded in 355 patients who underwent seed implantation. The percentage distribution of patients according to the difference between the flare peak and post-implant nadir was plotted to define significant increases in the scores. The clinicopathologic characteristics, treatment parameters, and post-implant dosimetric parameters were compared between the non-flare and flare groups. PSA bounce was defined as an elevation of ≥0.1 ng/mL or ≥0.4 ng/mL compared to the previous lowest value, followed by a decrease to a level at or below the pre-bounce value.

Results

A clinically significant increase required an IPSS increase of at least 12 points and an OABSS increase of at least 6 points based on a time-course analysis of total scores and the QOL index. Assessment only by IPSS failed to detect 40 patients (11%) who had urinary symptom flare according to the OABSS. Univariate and multivariate analyses revealed that patients treated with higher biologically effective doses and those without diabetes mellitus had higher risks of urinary flare. There was no statistical correlation between the incidence and time of urinary symptom flare onset and that of a PSA bounce.

Conclusions

To our knowledge, this is the first report to prove the clinical potential of the OABSS as an assessment tool for urinary symptom flare after seed implantation. Our findings showed that persistent lower urinary tract symptoms after seed implantation were attributed to storage rather than to voiding issues. We believe that assessment with the OABSS combined with the IPSS would aid in decision-making in terms of timing, selection of a treatment intervention, and assessment of the outcome.

Electronic supplementary material

The online version of this article (doi:10.1186/s12894-017-0251-1) contains supplementary material, which is available to authorized users.

Tumour and immune cell dynamics explain the PSA bounce after prostate cancer brachytherapy

BACKGROUND

Interstitial brachytherapy for localised prostate cancer may be followed by transient increases in prostate-specific antigen (PSA) that resolve without therapy. Such PSA bounces may be associated with an improved outcome but often cause alarm in the patient and physician, and have defied explanation.

METHODS

We developed a mathematical model to capture the interactions between the tumour, radiation and anti-tumour immune response. The model was fitted to data from a large cohort of patients treated exclusively with interstitial brachytherapy. Immunohistological analysis for T-cell infiltration within the same tumours was also performed.

RESULTS

Our minimal model captures well the dynamics of the tumour after therapy, and suggests that a strong anti-tumour immune response coupled with the therapeutic effect of radiation on the tumour is responsible for the PSA bounce. Patients who experience a PSA bounce had a higher density of CD3 and CD8 cells within the tumour that likely contribute to the PSA bounce and the overall better outcomes observed.

CONCLUSIONS

Our observations provide a novel and unifying explanation for the PSA bounce in patients with early prostate cancer and also have implications for the use of immune-based therapies in such patients to improve outcomes.

Curative brachytherapy for prostate cancer in African-Caribbean patients: A retrospective analysis of 370 consecutive cases

PURPOSE

Prostate cancer is the most frequent malignancy in African-Caribbean men, a population sharing common genetic traits with African-American (AA) but presenting also genomic and epidemiologic specificities. Despite socioeconomic disparities with French mainland, all patients were treated within the French state-financed equal-access health care system. In this study, we report biochemical outcomes of patients treated by brachytherapy in our department from 2005 to 2014 in an African-Caribbean population.

METHODS AND MATERIALS

Three hundred seventy consecutive patients receiving ¹²⁵I brachytherapy as a curative treatment for early-stage (localized) disease between 2005 and 2014 were recorded. Selected patients presented with low-risk disease: initial prostate-specific antigen (PSA) <10 ng/mL, clinical stage ≤ T2c, and Gleason score <7. Patients with intermediate risk of recurrence were also included on a case-to-case basis with prostate-specific antigen <15 or Gleason score 7 (3 + 4). Biochemical failure free-survival was defined according to the American Society for Radiation Oncology nadir+2 definition.

RESULTS

The 3-year and 5-year biochemical failure free-survival for the entire cohort were 98.3% and 91.6%, respectively. For patients with low- and intermediate-risk disease, the 5-year BBFS rates were 92.1% and 90.8%, respectively. In univariate and multivariate analyses, only Gleason score (<7 vs. 7; p =  0.030 vs. p < 0.05) was a significant predictor of biochemical failure. The overall rate of late and acute Grade 2 or higher genitourinary toxicity was 12.6% and 10.3%.

CONCLUSIONS

In this large single-center series, brachytherapy achieved excellent rates of medium-term biochemical control in both low and selected intermediate-risk localized prostate cancer in African-Caribbean patients. Brachytherapy seems to be an excellent choice of treatment, with excellent outcomes and limited morbidity for African-Caribbean populations.

Early and multiple PSA bounces can occur following high-dose prostate stereotactic body radiation therapy: Subset analysis of a phase 1/2 trial

PURPOSE

We hypothesized that high-dose stereotactic body radiation therapy (SBRT) would lead to faster time to nadir and lower nadir values compared with conventional radiation therapy experiences. We now report prostate-specific antigen (PSA) kinetics following high-dose SBRT in patients treated with radiation alone.

METHODS AND MATERIALS

Ninety-one patients were enrolled on the phase 1/2 dose escalation study of SBRT for localized prostate cancer. All patients with at least 36 months of follow-up and without hormone therapy were included in this analysis (n = 47). Treatment response parameters evaluated include time to nadir, nadir value, occurrence of PSA bounces (rise of ≥0.2 ng/mL followed by a subsequent fall), magnitude of bounces, duration of bounces, and correlation of bounces with clinical outcomes.

RESULTS

Median follow-up was 42 months (range, 36-78 months). Treatment dose levels were 45 Gy (n = 10), 47.5 Gy (n = 8), and 50 Gy (n = 29) in 5 fractions. Biochemical control rate was 98%. Median PSA at follow-up was 0.10 ± 0.20 ng/mL. Median time to nadir was 36 ± 11 months. A total of 24/47 (51.1%) patients had ≥1 PSA bounce. Median magnitude of PSA rise during bounce was 0.50 ± 1.2 ng/mL. Median time to first bounce was 9 ± 7.0 months. Median bounce duration was 3 ± 2.3 months for the first bounce and 6 ± 5.2 months for subsequent bounces. Prostate volumes <30 mL were associated with a decreased likelihood of bounce (P = .0202), and increasing prostate volume correlated with increasingly likelihood of having ≥2 bounces (P = .027). Patients reaching PSA nadir of ≤0.1 ng/mL were less likely to experience any bounce (P = .0044).

CONCLUSIONS

Compared with other SBRT experiences, our study demonstrated a higher PSA bounce rate, a similar or shorter median time to bounce, and a very low nadir. Prostate volume appears correlated with bounce.

Prostate specific antigen bounce after intensity-modulated radiation therapy in an Asian population

Objective

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.

Methods

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.

Results

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.

Conclusion

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.

Erectile function status is highly associated with prostate-specific antigen bounce in localized prostate cancer patients treated with permanent prostate brachytherapy

OBJECTIVES

To examine the relationship between erectile function status and prostate-specific antigen bounce after prostate brachytherapy for localized prostate cancer.

METHODS

We identified 154 patients who were followed up for at least 24 months after brachytherapy. Erectile function status was assessed prospectively before brachytherapy (baseline), and 3, 6, 12, 18, 24 and 36 months postoperatively using the International Index of Erectile Function-15 questionnaire. Prostate-specific antigen bounce was defined as an increase of at least 0.4 ng/mL from a previous prostate-specific antigen level with a subsequent decline equal to, or less than, the initial nadir without treatment. A logistic regression analysis was used to identify a significant set of independent predictors of prostate-specific antigen bounce after brachytherapy.

RESULTS

Prostate-specific antigen bounce was observed in 38 (24.7%) men. The prostate-specific antigen bounce group had a higher erectile function domain score, higher orgasmic function domain score, and higher total International Index of Erectile Function-15 score before (at baseline) and after brachytherapy (3, 6, 12, 18, 24 and 36 months after brachytherapy) than their counterparts (P < 0.05). Of the 77 patients who completed the International Index of Erectile Function-15 questionnaire 18 months after brachytherapy (the median time of prostate-specific antigen bounce), sexual desire and intercourse satisfaction domain scores, and total International Index of Erectile Function scores 18 months after brachytherapy correlated with the occurrence of prostate-specific antigen bounce. A multivariate analysis identified the intercourse satisfaction domain score 18 months after brachytherapy as an independent indicator for the occurrence of prostate-specific antigen bounce (P = 0.008).

CONCLUSIONS

International Index of Erectile Function-15 score seems to be correlated with the prostate-specific antigen bounce in prostate cancer patients undergoing brachytherapy, and an occurrence of prostate-specific antigen bounce seems to be more likely in those who are more sexually active.

Prostate-specific antigen bounce after curative brachytherapy for early-stage prostate cancer: A study of 274 African-Caribbean patients

BACKGROUND

Prostate cancer incidence in the African-Caribbean population ranks among the highest worldwide. We aim to evaluate the prostate-specific antigen (PSA) kinetics after brachytherapy, which so far remains unknown in this population.

METHODS AND MATERIALS

From 2005 to 2013, 371 patients received (125)I brachytherapy of 145 Gy for early-stage prostate cancer. Eligibility criteria were cTNM ≤T2c, Gleason score ≤7, and initial PSA ≤15 ng/mL. Pretreatment androgen deprivation therapy was allowed. PSA bounce was defined as an increase of ≥0.4 ng/mL, lasting ≥6 months, followed by a decrease without any anticancer therapy. We examined PSA kinetics during followup.

RESULTS

For the 274 patients with at least 24 months followup, median age was 62 years old (range, 45-76). Initial PSA was <10 ng/mL in 244 and 10-15 ng/mL in 30 patients; 40 received androgen deprivation therapy. With a median followup of 50 months (range, 24-125), PSA declined continuously in 168 (61%) patients, bounced in 87 (31%), and initially declined and then rose in 22 (8%) patients. Among these latter patients, 18 presented clinical recurrence. Mean bounce intensity was 2.0 ng/mL (median, 1.2; range, 0.4-12.4). Bounces occurred in average 12 months after brachytherapy. Patients with bounce were significantly younger: mean age 59 vs. 63 years old in patients without bounce, p <0.001. Bounce was also significantly associated with the immediate post-brachytherapy PSA, mean 4.0 among bounce cases vs. 2.9 among non-bounce cases, p < 0.001. Bounce was not associated with recurrence.

CONCLUSIONS

PSA bounce in our African-Caribbean population seemed earlier and was more intense than described in other populations. Early increase of PSA should not be ascribed to treatment failure.

Kinetics differences between PSA bounce and biochemical failure in patients treated with 125I prostate brachytherapy

OBJECTIVE

To determine the helpful factors to distinguish prostate-specific antigen failure from prostate-specific antigen bounce with large magnitude.

METHODS

From October 2004 to December 2009, 242 patients with prostate cancer treated with (125)I brachytherapy were analyzed, 88 patients were excluded because the follow-up durations were shorter than 5 years. Their median follow-up was 80.4 months (60.0-123.9). Prostate-specific antigen failure was determined using the Phoenix definition. Prostate-specific antigen bounce was defined as an increase ≥0.2 ng/ml above the nadir, followed by a spontaneous return to the nadir. Prostate-specific antigen bounce +2 was defined as a prostate-specific antigen rise by 2.0 ng/ml or more above the nadir.

RESULTS

The 5-year biochemical relapse-free survival rate was 90.2%. Prostate-specific antigen failure and prostate-specific antigen bounce +2 were seen in 23 patients (14.9%) and 12 patients (7.8%), respectively. On univariate analysis, age at implant (P = 0.028), T stage (P = 0.020), time to prostate-specific antigen failure or prostate-specific antigen bounce (time to onset) (P = 0.0008), prostate-specific antigen velocity (P = 0.0003) and prostate-specific antigen doubling time (P = 0.0004) were significant for the distinction between prostate-specific antigen failure and prostate-specific antigen bounce +2. On multivariate analysis, no factor was the statistically significant factor. On receiver operating characteristic curve analysis, time to onset with a cutoff value of 29.8 months, prostate-specific antigen velocity of 0.18 ng/ml/month and prostate-specific antigen doubling time of 6.3 months had the highest accuracy of 82.9, 82.9 and 82.9% for prostate-specific antigen failure, respectively.

CONCLUSIONS

Time to onset, prostate-specific antigen velocity and prostate-specific antigen doubling time would be helpful for distinction between prostate-specific antigen failure and prostate-specific antigen bounce +2.

Unusually high prostate-specific antigen bounce after prostate brachytherapy: Searching for etiologic factors

PURPOSE

Determine whether fat distribution, body mass index, or clinical and dosimetric factors are associated with prostate specific antigen (PSA) bounce (PSAb) of ≥1.6 ng/mL in patients treated with permanent seed (125)I prostate brachytherapy (PB).

METHODS AND MATERIALS

We identified 23 patients with a PSAb of ≥1.6 ng/mL. For each patient with a bounce, at least one control with similar age (age ± 2 years, n=31) was identified. Control patients had to have no bounce (≤0.2 ng/mL) and a most recent PSA of <1 ng/mL. CT at Day 30 after PB was used to determine the volume of subcutaneous adipose tissue, visceral adipose tissue, and peri-prostatic fat. Univariate and multivariate logistic models were used to assess the association between PSAb and adipose tissue distribution and clinical and dosimetric factors.

RESULTS

Mean patient age was 62.3 ± 5.3 years. Mean PSAb height was 2.7 ± 0.8 ng/mL, and mean time to bounce was 9.6 ± 4 months. More than 90% of the patients reached a PSA nadir before PSAb within 12 months post-PB. Patients showing PSAb were more likely to have a T1c disease vs. T2a (odds ratio = 18.87; 95% confidence interval: 2.32-454.55; p=0.019) and a lower seed activity per cc of prostate volume (odds ratio=0.02; 95% confidence interval=0.42-2.22; p=0.026). Neither fat distribution nor body mass index was associated with PSAb (p=0.11-0.597).

CONCLUSIONS

Clinical and dosimetric factors play a role in PSAb of ≥1.6 ng/mL. Fat distribution is not associated with a PSAb. There is presently no satisfactory theory to explain the etiology of PSAb.

[Role of hypofractionated radiotherapy in the treatment of prostate cancer: a review]

BACKGROUND

Radiotherapy of prostate cancers, over the last few years, has been an alternative choice to radical prostatectomy in the case of localised cancers as well as being the preferred treatment in both advanced localised cancers and those of the elderly. A conventional course of prostate radiotherapy consisting of four to five sessions a week, lasts between 7 and 8 weeks plus about one week of preparation.

MATERIALS AND METHODS

A systematic review of the scientific literature based on Pubmed, along with an exhaustive review of randomised studies presented at international congresses, have made it possible to analyse the numerous therapeutic regimens available other than the conventional normofractioned one (i.e. with doses per session ranging between 1.8 and 2.2 grays).

RESULTS

Five randomised trials reported since 2005, plus several thousand patients treated by stereotaxic radiotherapy, have given rise to numerous scientific questions; these alternative hypofractioned courses (dose per fraction higher than 2.2 grays) have a potentially enhanced antitumoral efficacity along with the practical advantages of a shortened duration of radiotherapy.

CONCLUSION

The aim of this analysis of the scientific literature on hypofractioning in prostate cancer radiotherapy is to gather all the scientific evidence we currently have at our disposal. Further mature results of future randomised trials will have to be examined before modifying current practice.

Minimal percentage of dose received by 90% of the urethra (%UD90) is the most significant predictor of PSA bounce in patients who underwent low-dose-rate brachytherapy (LDR-brachytherapy) for prostate cancer

BACKGROUND

To clarify the significant clinicopathological and postdosimetric parameters to predict PSA bounce in patients who underwent low-dose-rate brachytherapy (LDR-brachytherapy) for prostate cancer.

METHODS

We studied 200 consecutive patients who received LDR-brachytherapy between July 2004 and November 2008. Of them, 137 patients did not receive neoadjuvant or adjuvant androgen deprivation therapy. One hundred and forty-two patients were treated with LDR-brachytherapy alone, and 58 were treated with LDR-brachytherapy in combination with external beam radiation therapy. The cut-off value of PSA bounce was 0.1 ng/mL. The incidence, time, height, and duration of PSA bounce were investigated. Clinicopathological and postdosimetric parameters were evaluated to elucidate independent factors to predict PSA bounce in hormone-naïve patients who underwent LDR-brachytherapy alone.

RESULTS

Fifty patients (25%) showed PSA bounce and 10 patients (5%) showed PSA failure. The median time, height, and duration of PSA bounce were 17 months, 0.29 ng/mL, and 7.0 months, respectively. In 103 hormone-naïve patients treated with LDR-brachytherapy alone, and univariate Cox proportional regression hazard model indicated that age and minimal percentage of the dose received by 30% and 90% of the urethra were independent predictors of PSA bounce. With a multivariate Cox proportional regression hazard model, minimal percentage of the dose received by 90% of the urethra was the most significant parameter of PSA bounce.

CONCLUSIONS

Minimal percentage of the dose received by 90% of the urethra was the most significant predictor of PSA bounce in hormone-naïve patients treated with LDR-brachytherapy alone.

Interpreting a rising prostate-specific antigen after brachytherapy for prostate cancer

The aim of the present study was to review the English language literature on the topic of prostate-specific antigen bounce after brachytherapy and present a summary of the current knowledge. Although ultimately prostate-specific antigen is a reliable measure of success after prostate brachytherapy, it can be very misleading in the first 3 years because of the frequency with which temporary benign rises in prostate-specific antigen occur. We have reviewed the English language literature on the topic of prostate-specific antigen bounce under the following headings: prostate neoplasms, brachytherapy, biochemical definition of prostate-specific antigen failure, "benign prostate-specific antigen bounce" and "prostate-specific antigen spike". We included brachytherapy delivered as either low dose rate or high dose rate, and either as monotherapy or as a boost combined with external beam radiotherapy. A benign self-limited rise in prostate-specific antigen after prostate brachytherapy is seen in an average of 35% of patients, but increases in frequency with younger age. In patients aged less than 55 years, it is observed in up to 68%. Other factors, such as sexual activity, dose, prostate volume and the use of high dose rate versus low dose rate have been implicated in affecting the frequency of the benign bounce. Benign increases in prostate-specific antigen are frequent after prostate brachytherapy. It is important to recognize and correctly diagnose this phenomenon in order to avoid unnecessary salvage treatment.

Prostate-specific antigen spikes with ¹³¹Cs brachytherapy. Is there a difference with other radioisotopes?

PURPOSE

There is a suggestion that a dose-rate effect exists for the prostate-specific antigen (PSA) spike after brachytherapy. ¹³¹Cs is a newer radioisotope with a half-life of 9.7 days that is being used for prostate brachytherapy. There is no published data on the PSA spike with this radioisotope and the goal of this study was to quantify PSA spikes with ¹³¹Cs and compare it with published data for other isotopes.

METHODS AND MATERIALS

We have been maintaining a prospective database for all patients treated with ¹³¹Cs prostate brachytherapy at our institution. We selected patients for whom followup PSA was available for at least 24 months. The PSA spike was defined as an increase of 0.2 ng/mL, followed by a decline to prespike level.

RESULTS

One hundred twenty-three patients had monotherapy, whereas 32 had external beam radiation therapy followed by a brachytherapy boost. Median followup was 36 months and mean numbers of PSAs obtained were 7. Forty-six (29.7%) patients had a PSA spike. The mean time and duration for the PSA spike were 12.5 and 8.8 months, respectively. The mean magnitude of increase and mean PSA value at increase were 0.63 and 1.56 ng/mL, respectively.

CONCLUSIONS

The incidence of a PSA spike in our series is consistent with reported numbers for other radioisotopes. The occurrence of the spike at 12.5 months appears to be at the early end of the spectrum reported for (125)I, but the duration and magnitude are similar to other radioisotopes.

Permanent 125I-seed prostate brachytherapy: early prostate specific antigen value as a predictor of PSA bounce occurrence

Purpose

To evaluate predictive factors for PSA bounce after ¹²⁵I permanent seed prostate brachytherapy and identify criteria that distinguish between benign bounces and biochemical relapses.

Materials and methods

Men treated with exclusive permanent ¹²⁵I seed brachytherapy from November 1999, with at least a 36 months follow-up were included. Bounce was defined as an increase ≥ 0.2 ng/ml above the nadir, followed by a spontaneous return to the nadir. Biochemical failure (BF) was defined using the criteria of the Phoenix conference: nadir +2 ng/ml.

Results

198 men were included. After a median follow-up of 63.9 months, 21 patients experienced a BF, and 35.9% had at least one bounce which occurred after a median period of 17 months after implantation (4-50). Bounce amplitude was 0.6 ng/ml (0.2-5.1), and duration was 13.6 months (4.0-44.9). In 12.5%, bounce magnitude exceeded the threshold defining BF. Age at the time of treatment and high PSA level assessed at 6 weeks were significantly correlated with bounce but not with BF. Bounce patients had a higher BF free survival than the others (100% versus 92%, p = 0,007). In case of PSA increase, PSA doubling time and velocity were not significantly different between bounce and BF patients. Bounces occurred significantly earlier than relapses and than nadir + 0.2 ng/ml in BF patients (17 vs 27.8 months, p < 0.0001).

Conclusion

High PSA value assessed 6 weeks after brachytherapy and young age were significantly associated to a higher risk of bounces but not to BF. Long delays between brachytherapy and PSA increase are more indicative of BF.

High-dose-rate brachytherapy and external-beam radiotherapy for hormone-naïve low- and intermediate-risk prostate cancer: a 7-year experience

PURPOSE

To report clinical outcomes and early and late complications in 264 hormone-naïve patients with low- and intermediate-risk prostate cancer treated with high-dose-rate brachytherapy (HDR-BT) in combination with external-beam radiotherapy (EBRT).

METHODS AND MATERIALS

Between February 2000 and July 2007, 264 patients underwent HDR-BT in combination with EBRT as a treatment for their low- to intermediate-risk prostate cancer. The HDR-BT was performed using ultrasound-based implantation. The total HDR-BT dose was 18 Gy in 3 fractions within 24 h, with a 6-h minimum interval. The EBRT started 2 weeks after HDR-BT and was delivered in 25 fractions of 1.8 Gy to 45 Gy within 5 weeks.

RESULTS

After a mean follow-up of 74.5 months, 4 patients (1.5%) showed prostate-specific antigen progression according to the American Society for Radiation Oncology definition and 8 patients (3%) according to the Phoenix definition. A biopsy-proven local recurrence was registered in 1 patient (0.4%), and clinical progression (bone metastases) was documented in 2 patients (0.7%). Seven-year actuarial freedom from biochemical failure was 97%, and 7-year disease-specific survival and overall survival were 100% and 91%, respectively. Toxicities were comparable to other series.

CONCLUSIONS

Treatment with interstitial HDR-BT plus EBRT shows a low incidence of late complications and a favorable oncologic outcome after 7 years follow-up.

Dynamic gadolinium-enhanced perfusion MRI of prostate cancer: assessment of response to hypofractionated robotic stereotactic body radiation therapy

OBJECTIVE

The purpose of this study was to evaluate the utility of dynamic gadolinium-enhanced perfusion MRI for monitoring the response to robotic stereotactic body radiation therapy for prostate cancer.

MATERIALS AND METHODS

Eighty-seven patients with prostate cancer underwent dynamic gadolinium-enhanced MRI before robotic stereotactic body radiation therapy, and prostate volume was calculated. Pharmacokinetic analysis postprocessing software was used to generate colorized parametric maps showing perfusion of enhancing tumors. The transfer constant K(trans) was calculated for identified tumors. Follow-up MRI was performed 2 months after treatment for 22 patients, 6 months for 71 patients, 12 months for 54 patients, and 24 months for 27 patients with repeated measurements of prostate volume and K(trans).

RESULTS

Perfusion MRI depicted focal enhancing prostate tumors that correlated with the biopsy results in 82 of 87 patients (94%). The median K(trans) of tumors before robotic stereotactic body radiation therapy was 1.79 minutes(-1). Follow-up MRI showed decreases in the size and degree of enhancement of tumors. The median tumor K(trans) decreased to 1.21 minutes(-1) 2 months, 0.39 minutes(-1) 6 months, 0.30 minutes(-1) 12 months, and 0.22 minutes(-1) 24 months after treatment. Prostate volume had decreased 23% 2 months, 26% 6 months, 33% 12 months, and 37% 24 months after robotic stereotactic body radiation therapy. The corresponding median prostate-specific antigen concentration before treatment was 6.45 ng/mL. After treatment, the concentration was 2.90 ng/mL at 2 months, 1.30 ng/mL at 6 months, 1.10 ng/mL at 12 months, and 0.59 ng/mL at 24 months.

CONCLUSION

Dynamic gadolinium-enhanced MRI is a useful tool for monitoring the response of prostate cancer to robotic stereotactic body radiation therapy, yielding both qualitative and quantitative data.

[PSA bounce after brachytherapy with permanent seed implantation for prostate cancer]

PURPOSE

To evaluate prostate specific antigen (PSA) bounce that may occur as a time PSA rise phenomenon during follow up period after brachytherapy (BT) with permanent seed implantation for prostate cancer. (Materials and methods) Seven hundred and forty-six patients had undergone BT from November 2003 to April 2007 in a single institute, and of 130 patients who did not receive hormone therapy and had minimal 3-year follow up are analyzed. PSA bounce was defined as a rise of at least 0.4 ng/ml with spontaneous return to pre-bounce level or lower.

RESULT

Among the 130 patients, 40 patients (30.8%) developed PSA bounce, and median time to PSA bounce was 18 months after the BT. With univariate analysis, younger patients (P = 0.027) and larger prostate (P = 0.030) had statistically significant correlation with PSA bounce. With multivariate analysis, younger patients were identified as only independent factor for predicting PSA bounce. Eight patients out of 130 patients (6.2%) triggered the Phoenix definition (nadir + 2 ng/ml) of PSA failure, however, clinical failure was seen only in 3 patients, and other 5 patients were considered as PSA bounce.

CONCLUSION

PSA bounce is likely to occur in younger patients within 3 years after BT. It is clinically important to distinguish PSA bounce from PSA failure during following period after BT.

Does the outcome of prostate cancer patients with large prostates differ from small prostate size in permanent seed, low dose-rate brachytherapy?

OBJECTIVE

Brachytherapy has good results in the treatment of early prostate cancer (PC). The procedure is challenging in large prostates, and the optimal prostate volume for brachytherapy was previously defined as ≤40 ml. This study analysed the outcome of PC patients with small (group A) and large (group B) prostate volume in prospective data.

MATERIAL AND METHODS

The material consisted of 535 consecutive patients treated with brachytherapy in Kuopio University Hospital. The mean follow-up time was nearly 6 years. Prostate-specific antigen (PSA) failure was defined as PSA rising ≥2.0 μg/l above nadir. A PSA bounce was defined as a rise in PSA of ≥0.2 μg/l. The causes of death were recorded.

RESULTS

A bounce was recorded more frequently in group A (30%) than in group B (18%) (p = 0.006). A bounce correlated with young age predicted a favourable outcome in both groups. PSA failure rate was similar in both groups: 13% and 12% in groups A and B, respectively. Post-treatment PSA ≤0.5 μg/l was the only independent prognostic factor associated with PSA failure in both groups (p < 0.0001, both groups). PC survival was 98.4% in both groups. Overall survival was 91% and 94% in groups A and B, respectively (p = not significant).

CONCLUSIONS

There were no differences between the PC patients with small and large prostate volumes treated with brachytherapy with respect to PSA failure rate, PC survival or overall survival. All patients, independent of prostate size, are potential candidates for brachytherapy.

Relationship between prostate-specific antigen bounce body fat distribution and body mass index in permanent seed brachytherapy for prostate cancer

PURPOSE

To analyze the influence of body mass index (BMI) and adipose tissue distribution on prostate-specific antigen (PSA) bounce after iodine-125 prostate brachytherapy.

METHODS AND MATERIALS

We studied 20 patients who had PSA bounce (≥0.50ng/mL) after exclusive prostate brachytherapy. These patients were compared with 48 patients without a bounce (<0.50ng/mL). All patients in the comparison group had a followup of ≥24 months and a last PSA ≤0.5ng/mL. Within these 48 patients, there was a group matched for age (n=20). Univariate and multivariate logistic models were estimated to assess the association between age, baseline PSA, prostate volume, D(90), visceral fat (VF) volume, and BMI on PSA-bouncing status.

RESULTS

When comparing the patients with a bounce to those without, only BMI showed a significantly different distribution (mean, 25.18 vs. 27.47kg/m(2); p=0.0342). On a multivariate analysis, BMI had an odds ratio of 0.85 (95% confidence interval, 0.71-0.99, p=0.049), indicating that an increase of 1kg/m(2) in BMI is associated with a 15% reduction in the odds of having a bounce. In the univariate analysis with the matching patients, BMI was a significant predictor of a bounce (p=0.0147). In the multivariate conditional logistic model, BMI showed a trend toward an influence on a bounce (p=0.0615). All other factors, including VF, did not have any influence on a PSA bounce.

CONCLUSIONS

Patients with a lower BMI are more likely to experience a PSA bounce ≥0.50ng/mL. VF did not have an influence on a PSA bounce.

Early choline levels from 3-tesla MR spectroscopy after exclusive radiation therapy in patients with clinically localized prostate cancer are predictive of plasmatic levels of PSA at 1 year

PURPOSE

To investigate the time course response of prostate metabolism to irradiation using magnetic resonance spectroscopy (MRS) at 3-month intervals and its impact on biochemical control.

METHODS AND MATERIALS

Between January 2008 and April 2010, 24 patients with localized prostate cancer were prospectively enrolled in the Evaluation of the Response to Irradiation with MR Spectroscopy (ERIS) trial. All the patients had been treated with intensity-modulated radiation therapy with or without long-term adjuvant hormonal therapy (LTHT) and underwent 3-T MRS and prostate-specific antigen (PSA) assays at baseline and every 3 months thereafter up to 12 months.

RESULTS

After radiation, the mean normalized citrate level (citrate/water) decreased significantly over time, both in the peripheral zone (PZ) (p = 0.0034) and in the entire prostate (p = 0.0008), whereas no significant change was observed in mean normalized choline levels (choline/water) in the PZ (p = 0.84) and in the entire prostate (p = 0.95). At 6 months after radiation, the mean choline level was significantly lower in the PZ for patients with a PSA value of ≤0.5 ng/mL at 12 months (4.9 ± 1.7 vs. 7.1 ± 1.5, p = 0.0378). Similar results were observed at 12 months in the PZ (6.2 ± 2.3 vs. 11.4 ± 4.1, p = 0.0117 for choline level and 3.4 ± 0.7 vs. 16.1 ± 6.1, p = 0.0054 for citrate level) and also in the entire prostate (6.2 ± 1.9 vs. 10.4 ± 3.2, p = 0.014 for choline level and 3.0 ± 0.8 vs. 13.3 ± 4.7, p = 0.0054 for citrate level). For patients receiving LTHT, there was no correlation between choline or citrate levels and PSA value, either at baseline or at follow-up.

CONCLUSIONS

Low normalized choline in the PZ, 6 months after radiation, predicts which patients attained a PSA ≤0.5 ng/mL at 1 year. Further analyses with longer follow-up times are warranted to determine whether or not these new biomarkers can conclusively predict the early radiation response and the clinical outcome for patients with or without LTHT.

Tumor volume and metabolism of prostate cancer determined by proton magnetic resonance spectroscopic imaging at 3T without endorectal coil reveal potential clinical implications in the context of radiation oncology

PURPOSE

To determine whether a relationship exists between the tumor volume (TV) or relative choline content determined using magnetic resonance spectroscopy imaging (MRSI) at 3T and the clinical prognostic parameters for patients with localized prostate cancer (PCa).

METHODS AND MATERIALS

A total of 72 men (mean age, 67.8 ± 6.2 years) were stratified as having low-risk (n = 26), intermediate-risk (n = 24), or high-risk (n = 22) PCa. MRSI was performed at 3T using a phased-array coil. Spectra are expressed as the total choline/citrate, total choline plus creatine/citrate, and total choline plus polyamines plus creatine/citrate ratios. The mean ratio of the most pathologic voxels and the MRSI-based TV were also determined.

RESULTS

The mean values of the total choline/citrate, total choline plus creatine/citrate, and total choline plus polyamine plus creatine/citrate ratios were greater for Stage T2b or greater tumors vs. Stage T2a or less tumors: 7.53 ± 13.60 vs. 2.31 ± 5.65 (p = .018), 8.98 ± 14.58 vs. 2.56 ± 5.70 (p = .016), and 10.32 ± 15.47 vs. 3.55 ± 6.16 (p = .014), respectively. The mean MRSI-based TV for Stage T2b or greater and Stage T2a or less tumors was significantly different (2.23 ± 2.62 cm(3) vs. 1.26 ± 2.06 cm(3), respectively; p = .030). This TV correlated with increased prostate-specific antigen levels (odds ratio, 1.293; p = .012). Patients with high-risk PCa had a larger TV than did the patients with intermediate-risk PCa. A similar result was found for the intermediate-risk group compared with the low-risk group (odds ratio, 1.225; p = .041).

CONCLUSION

Biomarkers expressing the relative choline content and TV were significant parameters for the localization of PCa and could be helpful for determining the prognosis more accurately.

PSA bounce and biochemical failure after brachytherapy for prostate cancer: a study of 820 patients with a minimum of 3 years of follow-up

PURPOSE

To determine clinical or dosimetric factors associated with a prostate-specific antigen (PSA) bounce, as well as an association between a PSA bounce and biochemical relapse-free survival (bRFS), in patients treated with iodine-125 brachytherapy.

METHODS AND MATERIALS

A variety of clinical and treatment factors were examined in 820 patients who had a minimum of 3 years of PSA follow-up with T1-T2cN0M0 prostate cancer. Four different PSA threshold values were used for defining a PSA bounce: a PSA rise of ≥ 0.2, ≥ 0.4, ≥ 0.6, and ≥ 0.8 ng/mL.

RESULTS

A PSA bounce of ≥ 0.2, ≥ 0.4, ≥ 0.6, and ≥ 0.8 ng/mL was noted in 247 patients (30.1%), 161 (19.6%), 105 (12.8%), and 78 (9.5%), respectively. The median time to the first PSA rise was 17.4, 16.25, 16.23, and 15.71 months, respectively, vs. 34.35 months for a biochemical failure (p < 0.0001). A PSA rise of ≥ 0.2 ng/mL was the only definition for which there was a significant difference in bRFS between bounce and non-bounce patients. The 5-year bRFS rate of patients having a PSA bounce of ≥0.2 was 97.7% vs. 91% for those who did not have a PSA bounce (p = 0.0011). On univariate analysis for biochemical failure, age, risk group, and PSAs per year had a statistically significant correlation with PSA bounce of ≥ 0.2 ng/mL. On multivariate analysis, age and PSAs per year remained statistically significant (p < 0.0001 and p = 0.0456, respectively).

CONCLUSIONS

A bounce definition of a rise ≥ 0.2 ng/mL is a reliable definition among several other definitions. The time to first PSA rise is the most valuable factor for distinguishing between a bounce and biochemical failure.

3D MR-spectroscopic imaging assessment of metabolic activity in the prostate during the PSA "bounce" following 125iodine brachytherapy

PURPOSE

A temporary increase in prostate-specific antigen (PSA) values is observed in 30%-40% of men following (125)I brachytherapy (BT) for prostate cancer. We present the results of a study to characterize prostate metabolic activity during the PSA "bounce" and to correlate metabolic changes with PSA levels using three-dimensional magnetic resonance spectroscopic imaging (3D-MRSI).

METHODS AND MATERIALS

3D-MRSI was performed in 24 patients during the PSA bounce. Eight of these had also had a baseline 3D-MRSI scan before BT for the purpose of tumor mapping. The 3D-MRSI was repeated at 6- and 12-month intervals, and PSA levels were monitored every 3 months. Twenty-one of the patients had favorable-risk prostate cancer, and 3 had intermediate risk.

RESULTS

The choline+creatine signal intensity, although markedly reduced, was observable following BT. Diffuse activity not corresponding to original biopsy-positive sites was observed in 22 cases, and 2 cases were documented to have local recurrence. No statistically significant correlation between metabolic activity and PSA levels at each interval was found.

CONCLUSION

Post-BT prostate 3D-MRSI shows evidence of diffuse metabolic activity unrelated to residual malignancy. This supports the benign nature of the PSA bounce and suggests an inflammatory etiology. In the situation of a rising PSA, observation of focal activity on MRI/3D-MRSI could be a useful adjunct to suggest local recurrence at an earlier interval after brachytherapy when prostate biopsies would still be unhelpful. Longer follow-up is necessary to confirm the complex relationship between metabolic activity and PSA levels.

Prostate-specific antigen bounce after permanent iodine-125 prostate brachytherapy--an Australian analysis

PURPOSE

To report on prostate-specific antigen (PSA) "bounces" after (125)I prostate brachytherapy to review the relationship to biochemical control and correlate both clinical and dosimetric variables.

METHODS AND MATERIALS

We analyzed 194 hormone-naive patients with a follow-up of ≥ 3 years. Four bounce definitions were applied: an increase of ≥ 0.2 ng/mL (definition I), ≥ 0.4 ng/mL (definition II), ≥ 15% (definition III), and ≥ 35% (definition IV) of a previous value with spontaneous return to the prebounce level or lower.

RESULTS

Using definition I, II, III, and IV, a bounce was detected in 50%, 34%, 11%, and 9% of patients, respectively. The median time to onset was 14-16 months, the duration was 12-21.5 months, and the magnitude of the increase was 0.5-2 ng/mL. A magnitude of >2 ng/mL, fulfilling the criteria for biochemical failure (BF) according to the American Society for Therapeutic Radiology and Oncology Phoenix definition, was detected in 11.3%, 16.9%, 47.6%, and 50% using definitions I, II, III, and IV, respectively; 11 patients (5.7%) had true BF. The PSA bounces occurred earlier than BF (p < 0.001). The prediction of BF remains controversial and is probably unrelated to biochemical control. The only statistically significant factor predictive of a PSA bounce was younger age (definitions I and II).

CONCLUSION

PSA bounces are common after brachytherapy. All definitions resulted in a high number of false-positive calls for BF during the first 2 years. The definition of an increase of ≥ 0.2 ng/mL should be preferred because of the lowest number of false-positive results for BF. Patients experiencing a PSA bounce during the first 2 years after brachytherapy should undergo surveillance every 3-6 months. Additional investigations are recommended for elevated postimplant PSA levels that have not corrected by 3 years of follow-up.

PSA bounce after prostate brachytherapy with or without neoadjuvant androgen deprivation

PURPOSE

To assess the impact of PSA bounce (PB) on biochemical failure (BF) and clinical failure (CF) in brachytherapy patients treated with or without neoadjuvant androgen deprivation (AD).

METHODS AND MATERIALS

From 1987 to 2003, 691 patients with clinical stage T1-T3N0M0 prostate cancer were treated with external beam radiotherapy (EBRT) and high-dose-rate (HDR) brachytherapy boost (n=407), HDR brachytherapy alone (n=93), or permanent seed implant (n=191). Three hundred seventeen patients (46%) received neoadjuvant/adjuvant AD with RT. BF was scored using 3 definitions (ASTRO--3 rises, nadir+2 ng/ml, and threshold 3 ng/ml) based on current and absolute nadir (AN) methodologies. PB was defined as any increase in PSA followed by a decrease to the prior baseline or lower. The median followup was 4.0 years.

RESULTS

Forty-six patients (7%) experienced CF at 5 years. PB of >or=0.1, >or=1.0, and >or=2.0 ng/ml at any time after RT occurred in 330 (48%), 60 (9%), and 22 patients (3%) respectively. The use of an AN definition reduced the likelihood of scoring PB as BF across all levels. The patients receiving AD experienced significantly longer bounce duration. Bounce <1.0 ng/ml showed no association with CF. For bounce >or=1.0 ng/ml, 10% demonstrated CF vs. 6% without bounce of this amplitude (p=0.27). Bounces >or=1.0 ng/ml were more likely to be scored as BFs for definitions based on current nadir (3 rises: 20% vs. 13%, nadir+2: 43% vs. 11%, 3 at/after nadir: 57% vs. 12%) than those based on AN (3 rises: 8% vs. 10%, nadir+2: 18% vs. 11%, 3 at/after nadir: 13% vs. 11%).

CONCLUSIONS

Bounces >or=1.0 ng/ml are rare after brachytherapy with or without neoadjuvant AD, occurring in less than 10% of patients. Low PBs have little impact on BF, but as PB amplitude increases, the BF rate increases. BF definitions based on AN are less sensitive to PB after brachytherapy.

Prostate-specific antigen bounce after prostate brachytherapy: review of a confusing phenomenon

Prostate brachytherapy is a commonly used modality for the treatment of prostate cancer. After prostate brachytherapy, the prostate-specific antigen (PSA) level may fluctuate and increase temporarily without a clear reason in 30-40% of successfully treated men. This phenomenon is called "PSA bounce" and engenders anxiety on the part of the patient and physician. Having reviewed the literature we found 19 articles and summarized in the current review to delineate the facts of this relatively common and ambiguous phenomenon. Although several patient and treatment related factors were assessed by studies, only age remained as the most consistent predictor.

[Elevation of PSA after prostate radiotherapy: rebound or biochemical recurrence?]

The fact that external beam radiotherapy and brachytherapy are now considered to be curative techniques has led to major review of the modalities of follow-up after radiotherapy for prostate cancer. The problem concerns both the diagnosis of recurrence, rapidly announced by elevation of prostatic-specific antigen (PSA), usually at a subclinical stage, and the validity of criteria of biochemical recurrence to allow comparison of various study. Physicians involved in follow-up should be aware of the potential of bounce in PSA follow-up after external beam radiotherapy or brachytherapy. The PSA bounce phenomemon was defined by a rise of PSA values (+0.1 -0.8 ng/ml) with a subsequent fall. Biochemical failure after external beam radiotherapy or brachytherapy (with or without hormonotherapy) was defined by Phoenix criteria by a rise of 2 ng/ml above an initial PSA nadir. This definition was more correlated to PSA bounce phenomenon.

Prostate-specific antigen and prostate cancer: prediction, detection and monitoring

Testing for prostate-specific antigen (PSA) has profoundly affected the diagnosis and treatment of prostate cancer. PSA testing has enabled physicians to detect prostate tumours while they are still small, low-grade and localized. This very ability has, however, created controversy over whether we are now diagnosing and treating insignificant cancers. PSA testing has also transformed the monitoring of treatment response and detection of disease recurrence. Much current research is directed at establishing the most appropriate uses of PSA testing and at developing methods to improve on the conventional PSA test.

PSA Kinetics and PSA Bounce Following Permanent Seed Prostate Brachytherapy

PURPOSE

To report the incidence, timing, and magnitude of the benign prostate-specific antigen (PSA) bounce after 125I prostate brachytherapy and correlate the bounce with clinical and/or dosimetric factors.

METHODS AND MATERIALS

From March 1999 to August 2003, a total of 292 men received 125I prostate brachytherapy without androgen deprivation or supplemental beam radiotherapy and have PSA follow-up >30 months. Implants were preplanned using transrectal ultrasound (TRUS) and performed under transrectal ultrasound/fluoroscopy guidance using preloaded needles. A PSA bounce is defined as an increase >or=0.2 ng/ml with spontaneous return to prebounce level or lower.

RESULTS

Resolved PSA bounces were seen in 40% of men with follow-up >30 months. Median onset was 15 months, and median magnitude was 0.76 ng/ml. Magnitude >2 ng/ml was seen in 15%. The only clinical or dosimetric factor predictive of bounce in multivariate analysis was younger age. Median time to increasing PSA level indicative of failure was 30 months.

CONCLUSIONS

Benign PSA bounces are common after 125I prostate brachytherapy, especially in younger men. An increase >2 ng/ml above the nadir was seen in 15%. Magnitude of increase does not distinguish bounce from failure. Time to the start of the PSA increase can be helpful, but is not absolute. The PSA bounce does not predict subsequent failure. Caution is advised in interpreting an early increasing PSA level in the first 30 months after 125I brachytherapy in favorable-risk patients.

Isotope and Patient Age Predict for PSA Spikes After Permanent Prostate Brachytherapy

PURPOSE

To evaluate prostate-specific antigen (PSA) spikes after permanent prostate brachytherapy in low-risk patients.

METHODS AND MATERIALS

The study population consisted of 164 prostate cancer patients who were part of a prospective randomized trial comparing (103)Pd and (125)I for low-risk disease. Of the 164 patients, 61 (37.2%) received short-course androgen deprivation therapy. The median follow-up was 5.4 years. On average, 11.1 post-treatment PSA measurements were obtained per patient. Biochemical disease-free survival was defined as a PSA level of < or =0.40 ng/mL after nadir. A PSA spike was defined as an increase of > or =0.2 ng/mL, followed by a durable decline to prespike levels. Multiple parameters were evaluated as predictors for a PSA spike.

RESULTS

Of the 164 patients, 44 (26.9%) developed a PSA spike. Of the 46 hormone-naive (125)I patients and 57 hormone-naive (103)Pd patients, 21 (45.7%) and 8 (14.0%) developed a PSA spike. In the hormone-naive patients, the mean time between implantation and the spike was 22.6 months and 18.7 months for (125)I and (103)Pd, respectively. In patients receiving neoadjuvant androgen deprivation therapy, the incidence of spikes was comparable between isotopes ((125)I 28.1% and (103)Pd 20.7%). The incidence of spikes was substantially different in patients <65 years vs. > or =65 years old (38.5% vs. 16.3%). On multivariate Cox regression analysis, patient age (p < 0.001) and isotope (p = 0.002) were significant predictors for spike.

CONCLUSION

In low-risk prostate cancer, PSA spikes are most common in patients implanted with (125)I and/or <65 years of age. Differences in isotope-related spikes are most pronounced in hormone-naive patients.

Influence sur les résultats des rebonds du PSA après curiethérapie de prostate: étude de 295 cas avec trois ans de suivi

PURPOSE

To assess the frequency of the PSA "bouncing" phenomenon after a significant follow-up in a series of patients treated by permanent implant brachytherapy for a prostate cancer. To look for the clinical and dosimetric parameters possibly linked to this transitory secondary PSA increase. To evaluate in which percentage of cases this bouncing could have mimicked a biochemical relapse according to the ASTRO consensus criteria.

PATIENTS AND METHODS

From January 1999, to December 2001, 295 patients were treated by a permanent prostate implantation (real-time technique, with free (125)I seeds- Isoseed Bebig-) by the Institut Curie-Hôpital Cochin-Hôpital Necker Paris group. The mean follow-up is 40.3 months (9-66 months). The PSA level was regularly checked, at least every 6 months. We defined as a "bouncing" all increase in PSA, starting at 0.1 ng/ml, subsequently followed by a spontaneous (without any treatment) decrease, with return to the previous level or lower. We particularly focused on the patients fulfilling the criteria for a biochemical relapse according to the ASTRO consensus (Three successive increases in PSA). A multivariate analysis tried to identify independent factors among the usual clinical and dosimetric parameters.

RESULTS

In our series, 161 patients (55%) showed a transitory PSA increase (bouncing) of at least 0.1 ng/ml; 145 patients (49%) a bouncing of 0.2 ng/ml, 93 patients (32%) a bouncing of 0.4 ng/ml and 43 patients (15%) a bouncing of at least 1 ng/ml. Mean PSA bounce was 0.8 ng/ml (0.1-4.1), and mean time to bounce was 19 months. Thirty-two patients (11% of the total number) presented three successive PSA increases with a significant (3 months) interval between the dosages, and therefore were to be considered as being in biochemical relapse according to the ASTRO consensus criteria. Actually, among those 32 patients, 18 (56%) subsequently showed a complete normalization of their PSA, without any treatment. Ten patients went on increasing their PSA, and were considered to be really in biochemical relapse. For the last 4 patients, the situation still remains ambiguous. In multivariate analysis, age<70 years (P<0.00001) and D90>200 Gy (P<0.003) were identified as independent factors for a PSA bouncing of at least 0.4 ng/ml.

CONCLUSIONS

The observed rate of 32% of patients showing a PSA bouncing of at least 0.4 ng/ml in our series is in good agreement with what has been previously reported in the literature. Age<70 years and D90>200 Gy were found to be independent factors predicting for such a secondary transitory increase in PSA. Interestingly, among 32 patients fulfilling the classical criteria of the ASTRO for a biochemical relapse, 18 (56%) subsequently showed a spontaneous PSA decrease, demonstrating that the ASTRO consensus is not well adapted to the biochemical follow-up of our patients undergoing permanent implant prostate Brachytherapy.