Temporary PSA rises and repeat prostate biopsies after brachytherapy

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.

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.

Analysis of prostate-specific antigen bounce after I(125) permanent seed implant for localised prostate cancer

BACKGROUND AND PURPOSE

To report on the incidence of benign prostate-specific antigen bounce following permanent I(125) prostate brachytherapy, to describe the associations in our population and review the relationship of bounce to subsequent biochemical failure.

MATERIALS AND METHODS

From February 2000 to May 2005, 374 patients with localised prostate cancer were treated with I(125) permanent prostate brachytherapy at a single institution. A prospectively collected database was used to identify cases of prostate-specific antigen (PSA) bounce, defined as a rise of 0.2 ng/ml above an initial PSA nadir with subsequent decline to or below that nadir without treatment. The patients who received neo-adjuvant or adjuvant hormone manipulation were excluded. Biochemical failure was determined using the both the ASTRO consensus definition and Phoenix (nadir +2 ng/mL) definition.

RESULTS

Two hundred and five patients were identified with a median follow-up of 45 months (24-85). PSA bounce was noted in 79 (37%) men, occurring at a median of 14.8 months (1.7-40.6) following implant. The median peak PSA was 1.8 ng/ml (0.4-7.4) with a bounce magnitude of 0.91 ng/ml (0.2-5.8). When pre- and post-implant factors were assessed for association to bounce, only younger age was statistically significant (p=0.002). The threshold for biochemical failure as defined by the ASTRO consensus definition (1997) was met in 4 (5%) patients after experiencing bounce as opposed to 19 (15%) non-bounce patients (p=0.01). The threshold for Phoenix (nadir +2 ng/mL) was met in 6 (7.5%) patients following bounce versus 22 (17%) of non-bounce patients (p=0.003). Both definitions are prone to false positive calls during bounce. Median PSA velocity during the bounce was 0.08 ng/mL/month (0.02-0.98) and was statistically significantly lower than the median velocity prior to the Phoenix biochemical failure at 0.28 ng/mL/month (0.07-2.04) (p=0.0005).

CONCLUSION

PSA bounce is a common finding in our population and is associated with a lower rate of subsequent biochemical failure. The noted differences in PSA velocity will require verification in a future analysis to reduce the influence of median follow-up on this finding. Patients should be advised of the potential of bounce in PSA follow-up after permanent I(125) prostate brachytherapy and physicians involved in follow-up of prostate brachytherapy patients should be aware of this phenomenon, allowing them to commit to appropriate PSA surveillance, avoiding the premature and inappropriate initiation of salvage therapy during PSA bounce.

A second transient prostate-specific antigen elevation after external-beam radiation therapy and fractionated magnetic resonance imaging-guided high-dose rate brachytherapy boost

A 63-year-old man with a T1c adenocarcinoma of the prostate, Gleason score of 7 (4+3), and a pretreatment prostate-specific antigen (PSA) level of 9.5 ng/mL was treated with external-beam radiation therapy (45 Gy) and 2 magnetic resonance imaging-guided high-dose rate brachytherapy boosts (10 Gy each.) The patient also received neoadjuvant, concurrent, and adjuvant hormonal treatment with leuprolide for 7 months total. Without any further intervention the patient had 2 separate and prolonged PSA increases and decreases 12-35 months after therapy. His PSA nadir was <0.2 ng/mL and rose slowly over several months to 4.2 ng/mL, resolved, and then rose 2.3 ng/mL before again slowly resolving. After prostate irradiation, many patients experience a transient rise in serum PSA levels and a subsequent decline without any treatment. This is known as a PSA "bounce" or "bump." Some patients experience a second transient rise in PSA levels after irradiation. To our knowledge, this case report is the first documentation of a second PSA bump in a patient treated with external-beam radiation therapy and high-dose rate boost therapy and provides context to address concerns and therapeutic decisions confronting physicians and patients.

The current role of imaging for prostate brachytherapy

Prostate brachytherapy is a radiotherapy technique for early stage prostate cancer that uses imaging guidance to place radioactive sources directly into the prostate gland. Transrectal ultrasound is used to facilitate a template-guided transperineal approach to the prostate and permits a highly conformal method of prostate radiotherapy with doses far higher than can be achieved with other radiation techniques. Maturing data has validated this technique as an acceptable treatment option with favourable and durable biochemical outcomes. The radiologist has a major role to play in the process: patient selection, guiding source delivery and follow-up after treatment all require close collaboration with colleagues in Radiation Oncology and Medical Physics. This review emphasises the specific contribution of imaging in the context of currently reported outcomes data.

Six year experience of external beam radiotherapy, brachytherapy boost with a 1Ci 192Ir source, and neoadjuvant hormonal manipulation for prostate cancer

PURPOSE

To present preliminary outcomes of pulsed dose rate brachytherapy (PDR-BT), external beam radiotherapy (EBRT), and hormonal manipulation, for prostate cancer.

PATIENTS AND METHODS

Between December 1999 and January 2005, 165 consecutive patients with Stage T1-T3, N0, M0 prostate cancer were treated. Hormones were used in every patient. Median follow-up was 36 months. Risk groups were low (either Stage < or =T2a, +/- Gleason score < or =6, +/- Prostate-Specific Antigen [PSA] level < or =10 ng/mL); intermediate (either Stage T2b,c, +/- Gleason score 7, +/- PSA 10-20 ng/mL); and high (either Stage T3, +/- Gleason score 8-10, +/- PSA >20 ng/mL).

RESULTS

At 3 years, Radiotherapy Oncology Group (RTOG) Grade 3 and 4 genito-urinary toxicity was 4% and 1.4%; RTOG Grade 3 and 4 gastro-intestinal toxicity was 2.6% and 0%, respectively. Erectile preservation was 61%. Overall survival was 93% (154 of 165) and cause-specific survival was 98% (162 of 165). At 3 years, disease free survival (DFS) was 93% (153 of 165). DFS for low-, intermediate-, and high-risk groups was 100%, 97%, and 81%, respectively (chi(2) (2) = 16.02, p = 0.0003). The nadir plus 2 ng/mL definition (chi(2) (2) = 14.49, p = 0.0007) best predicted clinical failure, having the lowest false-positive rate (3 of 165). The nadir plus 2 ng/mL PSA-progression-free survival (PSA-PFS) rate was 100%, 95%, and 87% for the low-, intermediate, and high-risk groups, respectively. Overall ASTRO PSA-PFS rate was 88%.

CONCLUSIONS

Pulsed dose rate brachytherapy plus EBRT is effective in treating localized prostate cancer, with acceptable toxicity. However, a median 5-year PSA-PFS follow-up is required before providing a solid recommendation. This preliminary information supports continued use.

When Prostate Brachytherapy Fails: A Case Report and Discussion

For appropriately selected brachytherapy patients, prostate-specific antigen failure is uncommon. Our patient experienced biochemical failure after 125I brachytherapy treatment for low-risk prostate adenocarcinoma. We suggest neoadjuvant/adjuvant hormonal therapy combined with pelvic external-beam radiation therapy as a reasonable salvage treatment. At the 2-year follow-up, he is apparently doing well. With limited data available, salvage management for this situation is presently investigational.

High-dose-rate intensity-modulated brachytherapy with external beam radiotherapy for prostate cancer: California endocurietherapy’s 10-year results

PURPOSE

To present the long-term outcome and morbidity of high-dose-rate brachytherapy (HDR-BT) combined with external beam radiotherapy (EBRT) for localized prostate cancer.

METHODS AND MATERIALS

Between September 1991 and December 1998, 209 consecutive patients with no prior androgen suppression were treated with HDR-BT plus EBRT. The median follow-up was 7.25 years (range, 5-12 years). The patients were stratified into three risk groups: low (Stage T2a or less, Gleason score </=6, and prostate-specific antigen [PSA] level </=10 ng/mL), intermediate (Stage T2b,c, Gleason score 7, and PSA level 10-20 ng/mL), and high (Stage T3, Gleason score 8-10, and PSA level >20). Four definitions of PSA progression were compared with the general clinical failure outcome: the American Society for Therapeutic Radiology and Oncology (ASTRO) definition, nadir plus 2.0 ng/mL, two consecutive rises >/=0.5 ng/mL, and PSA level >0.2 ng/mL. Morbidity was scored using Radiation Therapy Oncology Group criteria.

RESULTS

The general clinical control rate was 90% (188 of 209), and the general clinical failure rate was 10% (21 of 209). The overall survival rate was 79%, and the cause-specific survival rate was 97%. The PSA progression-free survival (ASTRO definition) rate was 90%, 87%, and 69% for the low-, intermediate-, and high-risk groups, respectively. The nadir plus 2 ng/mL and two rises >/=0.5 definitions correlated better with the actual clinical outcome than did the ASTRO and PSA >0.2 ng/mL definitions. The rate of Grade 3 and 4 late urinary morbidity was 6.7% and 1%, respectively, mostly occurring in patients who had undergone post-RT transurethral prostate resection. No late Grade 3 or 4 rectal morbidity developed. The sexual potency preservation rate was 67%.

CONCLUSION

Our 10-year results have demonstrated HDR-BT plus EBRT is a proven treatment for all stages of localized prostate cancer. The morbidity was low, but post-RT transurethral resection should be avoided.

Prostate Specific Antigen Bounce After Simultaneous Irradiation for Prostate Cancer: The Relationship to Patient Age

PURPOSE

We report on the relationship of patient age to prostate specific antigen (PSA) bounce after brachytherapy for prostate cancer.

MATERIALS AND METHODS

From 1992 to 1997, 1,011 consecutive men with stage T1-T2NxM0 prostate cancer were treated with simultaneous irradiation, transperineal prostate I-125 implant followed by external beam irradiation. No patients received neoadjuvant hormones. There were 251, 491 and 269 men 60 years old or younger, 61 to 70 and 71 or older, respectively, at implant. PSA bounce is defined by a postirradiation PSA increase of 0.1 ng/ml or more above the level before bounce followed by a decrease to or below that level. Disease freedom is defined by a PSA cut point of 0.2 ng/ml. Median followup is 6 years (range 3 months to 10 years).

RESULTS

The frequency of PSA bounce according to age 60 or younger, 61 to 70 and 71 or older is 57%, 41% and 26%, respectively, a significant difference (p <0.000), average time to bounce onset is 19, 20 and 25 months for these 3 age groups, respectively, a significant difference (p = 0.002), and average bounce duration is 11, 8 and 8 months, respectively, a significant difference (p <0.000). On multivariate analysis of age, pretreatment PSA, Gleason score, stage, implant dose, prostate volume, diabetes and race, only age is significantly associated with PSA bounce (p <0.0001). After adjusting for the inherent bias caused by PSA bounce, there is no significant difference in disease-free survival between men with and without bounce.

CONCLUSIONS

Young men with prostate cancer treated with brachytherapy have a significantly higher frequency, earlier onset and longer duration of PSA bounce than older men.

Clinical correlates to PSA spikes and positive repeat biopsies after prostate brachytherapy

OBJECTIVES

To make some preliminary observations regarding the biochemical characteristics of the doubly confusing picture of prostate-specific antigen (PSA) spikes and histologically positive biopsies after prostate brachytherapy.

METHODS

All patients reported here had a pretreatment PSA level of less than 10 ng/mL and Gleason score of 4 to 6. Transperineal iodine-125 implants (without supplemental beam radiotherapy) were performed as previously described. After implantation, patients were followed up routinely, with repeat PSA measurements and physical examinations every 4 to 6 months. The timing of the postimplant PSA measurements was at the discretion of the patients and their doctors. No patient received preimplant or postimplant hormonal therapy. Repeat biopsies were performed from 13 to 31 months (median 22) after implant.

RESULTS

Patients' prespike nadir ranged from 0.9 to 1.7 ng/mL (median 1.2). The time from the implant to the start of the spike ranged from 9 to 24 months (median 13). The time from implant to the spike peak ranged from 12 to 30 months (median 22). The peak spike height ranged from 2.6 to 8.4 ng/mL (median 3.1). Patients' last PSA value ranged from 0.1 to 0.5 ng/mL (median 0.2).

CONCLUSIONS

Transient PSA rises can occur even in the presence of a persistently positive biopsy, and patients and physicians should not feel compelled to rush ahead with salvage therapy. On the basis of the patient data reported here, it appears that a spike up to 10 ng/mL is still consistent with cancer eradication.

Urinary symptom flare following I-125 prostate brachytherapy

PURPOSE

Although acute urinary morbidity after prostate brachytherapy has been well-documented, long-term effects have not been fully characterized. We describe a late complication of I-125 prostate brachytherapy we have termed urinary symptom flare.

METHODS AND MATERIALS

A total of 172 patients who underwent I-125 prostate brachytherapy between 1991 and 1998 completed a pretreatment and at least four follow-up International Prostate Symptom Score (IPSS) forms. Follow-up visits were made 1 month after implant and at 3- to 6-month intervals thereafter. Follow-up periods ranged from 12 to 106 months (median 41.5 months). The number of IPSS forms per patient ranged from 4 to 17 (median 6). A total of 32.6% of patients received both 3 months of neoadjuvant and 3 months of adjuvant hormonal therapy. Postimplant dosimetry revealed D90 values of 5578-25692 cGy (median 17290 cGy). The peak voiding score, indicating the time of the most severe urinary morbidity after brachytherapy, was defined as the highest rise in IPSS recorded after implantation. The nadir score was the lowest IPSS attained after the peak score, generally indicating a return to the patient's preimplant urinary function. A "flare" was defined as a rise in IPSS from the nadir score of at least five points, denoting a late exacerbation of urinary symptoms. Patients with a transient rise in PSA of 0.1 ng/ml or greater were considered to have a PSA bounce.

RESULTS

The mean pretreatment IPSS for the study population was 7.5. The mean peak IPSS was 19.4 and occurred from 0.1 to 25 months (median 1.3 months) after the date of implant. The mean nadir IPSS was 6.7 and occurred from 1.6 to 61.6 months (median 14.3) after brachytherapy. A total of 35.5% of patients (61/172) have experienced a urinary flare of 5 or more points, as measured by the IPSS form. The mean "flare" IPSS was 16.4. The time to develop a flare ranged from 5.8 to 64 months (median 23.9 months). The actuarial risk of developing a flare was 21% by 2 years, 34% by 3 years, 38% by 4 years, and 47% by five years. In 72% of patients (44/61) who developed a flare, the flare subsided to baseline by the next follow-up visit. Of the remaining patients, 3% (2/61) reached a baseline value two follow-up visits later. In 25% of the patients (15/61) who experienced a flare, it occurred during their last follow-up visit. No single factor, including PSA (p = 0.9), stage (p = 0.9), use of hormone therapy (p = 0.9), implanted activity (p = 0.1), ultrasound volume (p = 0.4), dose (p = 0.4), seed number (p = 0.4), or needle number (p = 0.9), had a significant effect on the risk of developing a flare. There was a trend for younger patients (<or=65 vs. >65, p = 0.07) to experience the urinary flare.

CONCLUSIONS

Acute symptoms after I-125 prostate brachytherapy appear to peak 1 month after a prostate implant and return to their baseline values at 1 year. A transient late exacerbation of urinary symptoms is common and can occur in up to half of all patients by 5 years. There appears to be no statistically significant association between a late exacerbation in urinary symptoms and clinical or implant parameters.

PSA bouncing after external beam radiation for prostate cancer with or without hormonal treatment

OBJECTIVES

The purpose of this study was to find out the frequency of PSA bouncing and the factors effecting PSA bounce after external beam radiation treatment (EBRT) with or without hormonal treatment (HT) for prostate cancer and to identify any possible relationship with biochemical control.

METHODS

Between March 1997 and November 2000, 72 consecutive patients with clinically localised prostate cancer were treated by EBRT with or without HT. All patients had a pretreatment PSA level, at least six post-treatment PSA levels and minimum two years of follow-up. Median follow-up for all patients was 51 months (range 25-69 months). Median radiation dose given to the center of the prostate was 70Gy (range 63-74Gy). Fifty-nine patients (82%) received adjuvant HT with median duration of six months. PSA bounce was defined as a minimal rise of 0.4ng/ml over six months (monthly rise > or =0.07 ng/ml), followed by any decrease. Biochemical failure was defined in accordance with the ASTRO consensus guidelines.

RESULTS

Seventeen patients (24%) experienced at least one PSA bounce. PSA bounces were more frequent in patients with T1-2 stage, pretreatment PSA <10 ng/ml, small field irradiation, radiation dose < or =70 Gy, PSA nadir > or =0.2 ng/ml and without HT. PSA bounce occurred in 54% of patients treated by EBRT only, and 17% of patients treated by EBRT and HT. Logistic regression model for multivariate analysis revealed the radiation field size as the only independent predictive factor for PSA bounce. Five-year biochemical control rates were 82% for non-bouncers and 88% for bouncers (p=0.5).

CONCLUSIONS

PSA bouncing occurs in approximately a quarter of patients treated with EBRT with or without HT. It is associated with pretreatment and treatment characteristics, but we did not observe any relationship with biochemical failure.

Permanent interstitial brachytherapy for the management of carcinoma of the prostate gland

PURPOSE

We summarize the permanent prostate brachytherapy literature, including biochemical outcomes, quality of life parameters and areas of controversy.

MATERIALS AND METHODS

The permanent prostate brachytherapy literature was reviewed using MEDLINE searches to ensure completeness.

RESULTS

Using various planning and intraoperative techniques the majority of the brachytherapy literature demonstrates durable biochemical outcomes for patients with low, intermediate and high risk features. For low risk patients there is no advantage to combining supplemental external beam radiation therapy with brachytherapy. In addition, supplemental external beam radiation therapy may not improve biochemical outcomes for patients at intermediate and high risk if the target volume consists of the prostate with a generous periprostatic margin. There is no defined role for adjuvant hormonal manipulation. Although a reliable set of pretreatment criteria to predict implant related morbidity is not available, severe urinary and rectal morbidity is rare. The incidence of brachytherapy induced erectile dysfunction is significantly greater than initially reported but the majority of patients respond favorably to sildenafil.

CONCLUSIONS

Continued refinements in brachytherapy planning and implementation techniques, postimplantation evaluation and continued elucidation of the etiology of urinary, bowel and sexual dysfunction should result in further improvements in biochemical and quality of life outcomes.

Atypia in nonneoplastic prostate glands after radiotherapy for prostate cancer: duration of atypia and relation to type of radiotherapy

It is unknown how long postradiation atypia of benign prostate glands persists and whether the type of radiation is a factor. Forty-four cases consisting of 37 needle biopsies and 7 transurethral resections of the prostate seen in consultation (January 1997 to September 2000) were studied. In two men (5%), the cases were initially sent without a history of radiotherapy. Thirteen patients had minimal cancer (one core) with the remaining showing no residual tumor. Twenty patients were treated with interstitial radiotherapy (brachytherapy) (IRT), 17 with external beam radiation (XRT), and 7 with a combination of both (CT). The time interval between the treatment and tissue sampling ranged from 8 to 72 months (mean 3 months). Slides were reviewed blindly to the type of radiation and the time interval. Radiation-induced atypia in nonneoplastic glands, stromal fibrosis, and vascular changes was scored separately 0-3, with 0 showing no radiation injury and grade 3 showing prominent nuclear atypia, stromal fibrosis, and vascular hyalinization. We derived a combined score for the epithelial atypia from 0 to 300 (% of glands x grade) for each biopsy. For each case, an overall grade from 0 to 3 was given separately for the stromal and vascular changes. Cases were divided into three groups based on time between treatment and biopsy: <24 months (n = 14), between 24 and 48 months (n = 19), and >48 months (n = 11). Because the scores for epithelial atypia with IRT and CT were the same, we combined them into one group. There was more atypia in cases treated with IRT/CT (mean score 190) than XRT (mean score 105) (p <0.00001). There was also a greater degree of stromal fibrosis with IRT/CT than XRT (p <0.04). There was no correlation between the type of treatment and the effect on vessels. There was no change over time in epithelial atypia in men treated with IRT/CT. With XRT, there was less epithelial atypia in cases biopsied >48 months after treatment (mean score 57) compared with those with a shorter interval between biopsy and treatment (mean score 132) (p = 0.02). Radiation atypia in benign prostate glands may persist for a long time after the initial treatment, resulting in a significant pitfall in evaluating prostate biopsies. Prominent radiation effect (100% of the glands showing grade 2 and 3 atypia) was detected up to 72 months in one of the patients treated with IRT. In some cases, the clinician may not be aware of a prior remote history of radiation or does not relay this history to the pathologist. The pathologist must recognize radiation atypia without relying on the clinician to provide this history. The type of radiation therapy (IRT/CT vs XRT) is a major factor in the degree and duration of postradiation epithelial atypia.

Prostate-specific antigen (PSA) velocity and benign prostate hypertrophy predict for PSA spikes following prostate brachytherapy

PURPOSE

To evaluate if variants of serum PSA or benign prostatic hypertrophy correlate with the development of a PSA spike following permanent prostate brachytherapy.

METHODS AND MATERIALS

Two-hundred-eighteen hormone-naïve patients with clinical T1b-T3a (1997 AJCC) prostate cancer who were treated with brachytherapy between August 1995 and November 1999, with or without supplemental external beam radiation therapy, and who remained free of biochemical failure were analyzed. The median follow-up was 46 months. A PSA spike was defined as a rise > or =0.2 ng/mL followed by a durable decline. Biochemical disease-free survival was defined by the ASTRO Consensus Definition with the additional constraint that the most recent PSA be < or =1.0 ng/mL. In addition, none of the patients possessed equivocal biochemical results (1 or 2 consecutive PSA rises or a declining PSA >1.0 ng/mL). In addition to previously reported clinical, treatment, and dosimetric parameters evaluated for spike, PSA density, transition zone (TZ) PSA density, percent free PSA, PSA velocity, PSA doubling time, TZ volume, and transition zone index (TZI) were included. The PSA kinetics of 18 hormone naïve patients who were implanted during the same time period and subsequently failed were also evaluated.

RESULTS

Fifty-two (23.9%) developed a PSA spike. Of the demographic and preimplant clinical parameters, patient age, TZ volume, TZI, TZ PSA density, and 125I were statistically significant predictors for a PSA spike. Of the postimplant parameters, V200, follow-up, first postimplant PSA, and most recent PSA predicted for a PSA spike. In multivariate Cox regression analysis, PSA nadir, TZI, follow-up, age, months to PSA nadir and preimplant PSA velocity were significant predictors for spike. However, when variables only determinable after a PSA spike were included in the multivariate analysis, TZI, age, PSA velocity, and first postimplant PSA were predictors for a spike. Using categorical cutpoints of TZI >0.25, age at implant <62 years, and first postimplant PSA >1.0 ng/mL in the regression analysis, a positive likelihood ratio for a PSA spike of >1.8 was noted for each variable. Patients with PSA progression displayed significantly different PSA kinetics than those with a spike.

CONCLUSIONS

In multivariate analysis, PSA nadir, TZI, patient age, months to PSA nadir, follow-up, and preimplant PSA velocity were predictive of a PSA spike. However, when only variables identifiable prior to a spike were evaluated, TZI, patient age, preimplant PSA velocity, and first postimplant PSA were the strongest predictors for a PSA spike.

A critical analysis of the interpretation of biochemical failure in surgically treated patients using the American Society for Therapeutic Radiation and Oncology criteria

PURPOSE

The use of prostate specific antigen (PSA) to indicate biochemical failure has become an accepted procedure to measure the effectiveness of therapy. Because long-term randomized studies comparing radiation modalities to radical prostatectomy are not available, use of biochemical recurrence as a surrogate measure of efficacy is increasing. Unfortunately, the definition of failure is not uniform among therapies. We evaluate how the American Society for Therapeutic Radiation and Oncology (ASTRO) criteria affect the interpretation of failure when applied to radical prostatectomy.

MATERIALS AND METHODS

We retrospectively reviewed data from 2,691 men who underwent anatomical radical prostatectomy for localized disease between 1985 and 2000. All patients had regular followup visits ranging from 6 months to 15 years (mean 6). No patients were treated with radiation or hormonal therapy preoperatively or postoperatively until clinical recurrence. Biochemical failure was defined as any measurable PSA 0.2 ng./ml. or greater. We evaluated how elements of the ASTRO criteria affected the failure rate when applied to this series. We looked at 1) backdating the failure date to the midpoint between nadir and first PSA greater than 0.2 ng./ml., 2) early censoring if only 1 or 2 increasing values were available and 3) defining failure after 3 consecutive PSA increases and backdating failure time (midpoint of nadir and first PSA increase).

RESULTS

Using actuarial analysis of the data defining failure as the first PSA 0.2 ng./ml. or greater, biochemical freedom from failure at 5, 10 and 15 years was 85%, 77% and 68%, respectively. In contrast, when backdating was used in this series, almost all failures occurred early with rare late failures (freedom from failure 82%, 80% and 80% at 5, 10 and 15 years, respectively). The difference in failure became even more pronounced when ASTRO criteria were applied requiring 3 consecutive increases, and backdating failure to the midpoint between nadir and first PSA (freedom from failure 90%, 90% and 90% at 5, 10 and 15 years, respectively).

CONCLUSIONS

The application of ASTRO criteria to a mature series of surgically treated patients with localized prostate cancer produced an apparent improvement in the probability of being biochemically free of disease at 15 years from 68% to 90%. Until prospective trials comparing these different therapies become available, caution should be exercised when interpreting outcomes between series due to the inherent differences in definition of biochemical failure.

Prostate-specific antigen spikes after permanent prostate brachytherapy

PURPOSE

To evaluate whether any clinical, treatment, or dosimetric parameters correlated with the development of a prostate-specific antigen (PSA) spike after permanent prostate brachytherapy.

METHODS AND MATERIALS

The evaluated population consisted of 218 hormone-naive patients free of biochemical or clinical failure who underwent permanent prostate brachytherapy with or without supplemental external beam radiotherapy for clinical Stage T1b-T3a adenocarcinoma of the prostate gland (1997 AJCC) between August 1995 and November 1999. No patient underwent pre- or postimplant hormonal manipulation, pretreatment seminal vesicle biopsy, or pathologic lymph node staging. In addition, none of the 218 patients possessed equivocal biochemical results (one or two consecutive PSA rises or a declining PSA >1.0 ng/mL). The median patient follow-up was 46.2 months. A PSA spike was defined as a rise of >or=0.2 ng/mL, followed by a durable decline. The clinical parameters evaluated included patient age, clinical T stage, Gleason score, pretreatment PSA level, prostate volume, brachytherapy planning volume, and patient follow-up in months. The evaluated treatment parameters included isotope and use of supplemental external beam radiotherapy. The dosimetric parameters evaluated included the minimal dose received by 90% of the prostate gland (D(90)), the percentage of the prostate volume receiving 100% (V(100)), 150%, and 200% (V(200)) of the prescribed minimal peripheral dose, and the mean, median, maximal, and minimal urethral doses. Biochemical disease-free survival was defined by the American Society for Therapeutic Radiology and Oncology consensus definition with the additional constraint that the most recent PSA level was <or=1.0 ng/mL.

RESULTS

Fifty-two patients (23.9%) developed a PSA spike at a mean and median of 19.5 +/- 9.4 months and 16.3 months (range 6.5-59.9), respectively. The median serum PSA before the PSA spike was 0.50 ng/mL, and the median PSA at the time of the spike was 0.90 ng/mL (range 0.3-3.0). On average, patients experiencing a PSA spike were 3.4 years younger (63.9 vs. 67.3 years, p = 0.002) than patients not experiencing a spike and were more likely to have been implanted with 125I than with 103Pd (32.7% vs. 16.7%, p = 0.006). In addition, the mean first postimplant PSA level was significantly higher in the spike than in the nonspike patients (1.2 vs. 0.7 ng/mL, p <0.001). By 66 months, the mean and median serum PSA levels for the spike and nonspike patients were all <or=0.1 ng/mL. Stratified into three nadir PSA groups, patients with a nadir PSA <or=0.2 ng/mL were significantly less likely to develop a PSA spike than those patients with a PSA nadir >0.2 to <or=0.5 ng/mL or >0.5 to 1.0 ng/mL (20%, 50%, and 80%, respectively, p <0.001). In Cox multivariate regression analysis, patient age, clinical stage, first postimplant PSA level, and V(150) were predictive for the development of a PSA spike. A postimplant dosimetric threshold of either <115% of the minimal peripheral dose for D(90) or <55% of the prostate volume for V(150) was strongly predictive of a spike. When the variables only determinable after the occurrence of the PSA spike were included in the multivariate analysis, V(150), preimplant PSA level, and nadir PSA were the significant predictors.

CONCLUSION

Of the patients, 23.9% developed a PSA spike with a median time to development of 16.3 months and a median prespike and median postspike PSA of 0.50 ng/mL and 0.90 ng/mL, respectively. In multivariate analysis, patient age, clinical stage, first postimplant PSA level, and V(150) were predictive for the development of a PSA spike. At approximately 66 months after implantation, the PSA curves converged for spike and nonspike patients, with a median PSA level <0.1 ng/mL.