Assessing the variability of outcome for patients treated with localized prostate irradiation using different definitions of biochemical control

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Baechu-kimchi is a traditional Korean dish of fermented vegetables, in which kimchi cabbage is the major ingredient. Seafood is added to baechu-kimchi in coastal areas, giving this dish regional diversity. However, little is known about how the addition of seafood affects the bacterial diversity of kimchi. Therefore, in this study, the bacterial diversity of five varieties of baechu-kimchi with seafood and one variety of baechu-kimchi without seafood was analyzed using culture-independent techniques. In 81.7% of all kimchi analyzed, the predominant species were members of the phylum Firmicutes and the lactic acid bacteria, Latilactobacillus sakei, Leuconostoc mesenteroides, Pediococcus inopinatus, and Weissella koreensis. These organisms were similar to those identified in baechu-kimchi without the addition of seafood, which was used as a control group, and bacterial community of previously reported kimchi. Therefore, the results of this study confirmed that the addition of seafood did not significantly affect the bacterial community in baechu-kimchi.

Quality characteristics of soybean fermented by Mucor, Rhizopus, and Aspergillus from meju

Three candidate starter strains-Aspergillus oryzae SNU-G, Mucor sp. KACC 46077, and Rhizopus oryzae KACC 40256-were inoculated into soybean, as individual strains or in combination, to assess their roles in fermentation. All the strains increased the pH, amino-type nitrogen, and moisture content of the soybean during fermentation, and decreased the lightness, redness, and yellowness. The inoculated strains increased to an average density of 1.37 × 10⁸ spores/g (from the initial 5.0 × 10⁷ spores/g) after 20 days of fermentation. Forty-two volatile compounds, including an acid, alcohols, carbonyls, furans, and a pyrazine, were more abundant in soybean fermented with starters than in controls. A. oryzae SNU-G increased the pH more than the other strains and produced more volatile alcohol compounds. R. oryzae KACC 40256 resulted in the lowest reduction of redness and yellowness during the fermentation and produced large amounts of carbonyl compounds, including two specific volatile compounds, 2-hydroxy-3-methylcyclopent-2-en-1-one and (3E)-3-ethyl-2-methylhexa-1,3-diene. Mucor sp. KACC 46077 contributed the least to pH change and volatile compound production, and did not produce specific volatile compounds. Although no significant synergy in the production of volatile compounds was found when using mixtures of strains compared with application of single strains, the quality of fermented soybeans was confirmed to be different depending on the strain(s) applied.

Bacterial Community of Galchi-Baechu Kimchi Based on Culture-Dependent and - Independent Investigation and Selection of Starter Candidates

In this study, the bacterial community of galchi-baechu kimchi was determined using culture-based and culture-independent techniques (next generation sequencing:NGS), and showed discrepancies between results. Weissella koreensis and Pediococcus inopinatus were the dominant species according to the NGS results, while Bacillus species and P. inopinatus were dominant in the culture-dependent analysis. To identify safe starter candidates, sixty-five Bacillus strains isolated from galchi-baechu kimchi using culture-dependent methods were evaluated for their antibiotic resistance, presence of toxin genes, and hemolytic activity. Strains were then assessed for salt tolerance and protease and lipase activity. As a result, four strains-B. safensis GN5_10, B. subtilis GN5_19, B. velezensis GN5_25, and B. velezensis GT8-were selected as safe starter candidates for use in fermented foods.

Analysis of second malignancies after modern radiotherapy versus prostatectomy for localized prostate cancer

PURPOSE

To clarify the risk of developing second primary cancers (SPCs) after radiotherapy (RT) versus prostatectomy for localized prostate cancer (PCa) in the modern era.

METHODS

The RT cohort consisted of 2120 patients matched on a 1:1 basis with surgical patients according to age and follow-up time. RT techniques consisted of conventional or two-dimensional RT (2DRT, 36%), three-dimensional conformal RT and/or intensity modulated RT (3DCRT/IMRT, 29%), brachytherapy (BT, 16%), and a combination of 2DRT and BT (BT boost, 19%).

RESULTS

The overall SPC risk was not significantly different between the matched-pair (HR 1.14, 95% CI 0.94-1.39), but the risk became significant >5years or >10years after RT (HR 1.86, 95% CI 1.36-2.55; HR 4.94, 95% CI 2.18-11.2, respectively). The most significant sites of increased risk were bladder, lymphoproliferative, and sarcoma. Of the different RT techniques, only 2DRT was associated with a significantly higher risk (HR 1.76, 95% CI 1.32-2.35), but not BT boost (HR 0.83, 95% CI 0.50-1.38), 3DCRT/IMRT (HR 0.81, 95% CI 0.55-1.21), or BT (HR 0.53, 95% CI 0.28-1.01).

CONCLUSIONS

Radiation-related SPC risk varies depending on the RT technique and may be reduced by using BT, BT boost, or 3DCRT/IMRT.

Higher-than-conventional radiation doses in localized prostate cancer treatment: a meta-analysis of randomized, controlled trials

PURPOSE

To determine in a meta-analysis whether the outcomes in men with localized prostate cancer treated with high-dose radiotherapy (HDRT) are better than those in men treated with conventional-dose radiotherapy (CDRT), by quantifying the effect of the total dose of radiotherapy on biochemical control (BC).

METHODS AND MATERIALS

The MEDLINE, EMBASE, CANCERLIT, and Cochrane Library databases, as well as the proceedings of annual meetings, were systematically searched to identify randomized, controlled studies comparing HDRT with CDRT for localized prostate cancer. To evaluate the dose-response relationship, we conducted a meta-regression analysis of BC ratios by means of weighted linear regression.

RESULTS

Seven RCTs with a total patient population of 2812 were identified that met the study criteria. Pooled results from these RCTs showed a significant reduction in the incidence of biochemical failure in those patients with prostate cancer treated with HDRT (p < 0.0001). However, there was no difference in the mortality rate (p = 0.38) and specific prostate cancer mortality rates (p = 0.45) between the groups receiving HDRT and CDRT. However, there were more cases of late Grade >2 gastrointestinal toxicity after HDRT than after CDRT. In the subgroup analysis, patients classified as being at low (p = 0.007), intermediate (p < 0.0001), and high risk (p < 0.0001) of biochemical failure all showed a benefit from HDRT. The meta-regression analysis also detected a linear correlation between the total dose of radiotherapy and biochemical failure (BC = -67.3 + [1.8 x radiotherapy total dose in Gy]; p = 0.04).

CONCLUSIONS

Our meta-analysis showed that HDRT is superior to CDRT in preventing biochemical failure in low-, intermediate-, and high-risk prostate cancer patients, suggesting that this should be offered as a treatment for all patients, regardless of their risk status.

Unification of a common biochemical failure definition for prostate cancer treated with brachytherapy or external beam radiotherapy with or without androgen deprivation

PURPOSE

Minimal data are available regarding selection of an optimal biochemical failure (BF) definition for patients treated with brachytherapy, external beam radiotherapy (EBRT), and combinations of these treatments with or without androgen deprivation (AD). We retrospectively analyzed our institution's experience treating localized prostate cancer in an attempt to determine a BF definition that could be applied for these various treatment modalities.

METHODS AND MATERIALS

A total of 2376 patients with clinical stage T1-T3 N0 M0 prostate cancer were treated with conventional dose (median, 66.6 Gy) EBRT (n = 1201), high-dose (median, 75.6 Gy) adaptive radiation therapy (n = 465), EBRT + high-dose-rate brachytherapy boost (n = 416), or brachytherapy alone (n = 294) between 1987 and 2003. A total of 496 patients (21%) received neoadjuvant AD with radiation therapy. There were 21924 posttreatment prostate-specific antigen (PSA) measurements. Multiple BF definitions were tested for their sensitivity, specificity, positive predictive value (+PV), and negative PV (-PV) in predicting subsequent clinical failure (CF) (any local failure or distant metastasis), overall survival (OS), and cause-specific survival (CSS). Median follow-up was 4.5 years. The date of BF was the date BF criteria were met (e.g., date of third rise).

RESULTS

A total of 290 patients (12%) experienced CF at a median interval of 3.6 years (range, 0.2-15.2 years). The 5- and 10-year CF rates were 12% and 26%, respectively. Three consecutive rises yielded a 46% sensitivity and 84% specificity for predicting CF. The 10-year CF for those 475 patients who experienced three rises (BF) was 37% vs. 17% for those patients who did not meet these criteria (biochemically controlled [BC]). For all patients, the following definitions were superior to three rises for predicting CF for both +PV, and -PV: n + 1 (> or =1 ng/mL above nadir), n + 2, n + 3, threshold 2 (any PSA > or =2.0 ng/mL at or after nadir), threshold 3, threshold 4, and threshold 5. For the subset of patients treated with EBRT alone, the n + k definitions and threshold k definitions maintained superior predictive capacity. However, the threshold k definitions seemed to maintain a slightly greater separation in 10-year CF rates (43% for BF vs. 13% for BC = 30% difference for threshold 3). Surprisingly, all definitions generally had better predictive capacity for those patients who received brachytherapy or neoadjuvant AD vs. EBRT alone. The endpoints appeared similar for n + 1 vs. threshold 3 and n + 2 vs. threshold 4 in EBRT alone patients, but for brachytherapy or neoadjuvant AD patients, there were similarities for n + 2 vs. threshold 3 and n + 3 vs. threshold 4. This may be a reflection of the lower nadir levels in patients receiving AD (median <0.1 ng/mL vs. 0.2 ng/mL for brachytherapy vs. 0.8 ng/mL for EBRT alone, p < 0.01). When examining CF correlation for the various classes of BF definitions, the threshold k definitions clearly demonstrated the greatest area under the receiver operating characteristic curve, followed by the n + k definitions. For OS, the threshold k definitions again demonstrated the greatest area under the curve, followed by definitions based on specific nadir cutoffs (nadir > or =k ng/mL).

CONCLUSIONS

Biochemical failure definitions applying a PSA threshold at or after the nadir (e.g., threshold 3) demonstrated the highest association with CF, OS, and CSS for all assessed treatment modalities. Definitions incorporating a PSA increase above the nadir value (e.g., nadir + 2 ng/mL) were also superior for all modalities. In general, BF definitions have greater predictive capacity for clinical outcome with brachytherapy or neoadjuvant AD than EBRT alone, possibly because of less "noise" from production of background PSA.

Defining biochemical failure after radiotherapy with and without androgen deprivation for prostate cancer

PURPOSE

To compare several characteristics of alternative definitions of biochemical failure (BF) in men with extended follow-up after radiotherapy (RT) with or with androgen deprivation therapy (ADT) for prostate cancer.

METHODS AND MATERIALS

From December 1, 1991, to April 30, 1998, 688 men with Stage T1c-T3NX-N0M0 prostate cancer received RT alone (n = 586) or RT plus ADT (n = 102) with a minimal follow-up of 4 years and five or more "ADT-free" posttreatment prostate-specific antigen levels. BF was defined by three methods: (1) the ASTRO definition (three consecutive rises in prostate-specific antigen level); (2) a modified American Society for Therapeutic Radiology Oncology (ASTRO) definition requiring two additional consecutive rises when a decline immediately subsequent to three consecutive rises occurred; and (3) the "Houston" or nadir plus 2-ng/mL definition (a rise of at least 2 ng/mL greater than the nadir). The sensitivity, specificity, positive predictive value, negative predictive value, and overall accuracy were determined for each using clinical progression as the endpoint. Furthermore, the misclassification rates for a steadily rising prostate-specific antigen level, ability to satisfy the proportional hazards (RT with or without ADT), effects of short follow-up, and intervals to the diagnosis of BF were compared.

RESULTS

The misclassification rate for BF using the nadir plus 2-ng/mL definition was 2% for RT alone and 0% for RT plus ADT compared with 0% and 0% for the modified ASTRO definition, and 5% and 23% for the ASTRO definition, respectively. The hazard rates for RT alone and RT plus ADT were proportional only for the nadir plus 2 ng/mL definition and seemingly unaffected by the length of follow-up. For RT with or without ADT, the nadir plus 2 ng/mL definition was the most specific (RT, 80% vs. RT plus ADT, 75%) with the greatest positive predictive value (RT, 36% vs. RT plus ADT, 25%) and overall accuracy (RT, 81% vs. RT plus ADT, 77%). A greater proportion of BF was diagnosed in the first 2 years of follow-up with the nadir plus 2 ng/mL definition compared with the ASTRO definition (13% vs. 5%, p = 0.0138, chi-square test).

CONCLUSION

The nadir plus 2 ng/mL definition was the best predictor of sustained, true, biochemical, and clinical failure, and was not affected by the use of ADT or follow-up length.

DEFINING RECURRENCE AFTER RADIATION FOR PROSTATE CANCER

PURPOSE

We reviewed prostate specific antigen (PSA) definitions of recurrence after external beam radiation for prostatic cancer and related them to the definitions used for other treatment modalities.

MATERIALS AND METHODS

The literature on defining recurrence after external beam radiation, brachytherapy and prostatectomy for prostate cancer was reviewed through a MEDLINE search to ensure completeness and the inclusion of all pertinent information.

RESULTS

Although the definition, which is the current standard for estimating recurrence after external beam radiation, has proved to be a reasonable measure, alternative options that are more sensitive and specific have now been defined. Similar statistical testing and comparison must also be done for other treatment modalities since the choice of failure definitions has not been evaluated nearly as thoroughly for these therapies. As much as possible, outcome reporting should be done according to the same method to ensure fairness when comparisons are made. However, inherent differences between treatment modalities and their effect on PSA production must also be considered.

CONCLUSIONS

With the latest available information from patients with long-term followup PSA definitions of tumor recurrence after external beam radiation for prostatic cancer must again be reviewed in a consensus conference format. The application of a universal PSA definition of tumor recurrence across multiple treatment modalities should also be explored.

LIMITATIONS IN THE USE OF SERUM PROSTATE SPECIFIC ANTIGEN LEVELS TO MONITOR PATIENTS AFTER TREATMENT FOR PROSTATE CANCER

PURPOSE

We reviewed the literature to help clarify the benefits and/or hazards associated with monitoring serum prostate specific antigen (PSA) after treatment with surgery or radiation therapy (RT) for nonmetastatic prostate cancer.

MATERIALS AND METHODS

A search was performed for 1990 to 2004 using the MEDLINE database, CancerLit database and reference lists of relevant studies to obtain articles addressing the use of serum PSA to follow patients after treatment for prostate cancer. Studies were reviewed to determine 1) if serial PSA monitoring provides an early and accurate surrogate assessment of cancer cure or treatment failure, 2) if any pattern in the PSA profile after treatment provides conclusive evidence of early local vs systemic failure, 3) the magnitude of the lead time to clinical failure that serial PSA monitoring may provide and 4) if the early identification of biochemical failure (BF) with earlier intervention improves outcome.

RESULTS

Although a lower PSA nadir after treatment with RT has been associated with cancer cure, 5% to 25% of patients ultimately have failure (beyond 5 years) even with the most optimal biochemical response. The most appropriate BF definitions to use after treatment for prostate cancer with RT remains controversial due to substantial differences in their accuracy, sensitivity, specificity and positive predictive value for clinical outcome. No pattern of PSA kinetics after treatment has conclusively been associated with a specific recurrence site. Biochemical failure definitions in patients treated with RT appear to provide a 6 to 18 month lead time to clinical failure but there are only limited published data to suggest that early intervention of any type (androgen deprivation, RT, surgery, etc) impacts survival.

CONCLUSIONS

The overall benefit of monitoring serum PSA after treatment for prostate cancer remains controversial. Considering the potential dangers associated with incorrectly assuming the efficacy of new forms of treatment, the toxicity of administering salvage therapies of uncertain efficacy after BF has been identified and the anxiety associated with tracking posttreatment serum PSA, additional studies must be done to determine the appropriate use of this marker in properly treating patients after therapy.

Biochemical failure and the temporal kinetics of prostate-specific antigen after radiation therapy with androgen deprivation

PURPOSE

The accuracy of the American Society of Therapeutic Radiation Oncology consensus definition of biochemical failure (BF) after radiation therapy (RT) and androgen deprivation (AD) has been questioned, because posttreatment prostate-specific antigen (PSA) levels typically rise after release from AD, and misclassification of BF may be made. The temporal kinetics of posttreatment PSA levels was examined to define the error in the classification of BF.

METHODS AND MATERIALS

Between December 1, 1991 and April 30, 1998, 688 men with T1c-T3 NX/0 M0 prostate cancer received three-dimensional conformal RT alone (n = 586) or in combination with either short-term (STAD: 3 to 12 months, n = 82) or long-term (LTAD: 12 to 36 months, n = 20) AD. Follow-up, calculated from the end of all treatment, was >/=48 months. The mean posttreatment PSA was calculated in 3-month intervals.

RESULTS

The median posttreatment clinical follow-up period was 76 months (range, 48-152 months). The posttreatment PSA values from the end of all treatment for the RT+STAD-BF group showed an initial period of rise followed by a period of decline at 30 months and then a continued rise again. The decline in the mean posttreatment PSA is explained in part by stabilization in PSA level after 3 consecutive rises. Nonbiochemical failures (NBF) after RT+STAD had a relatively constant mean PSA over time of approximately 0.5 ng/mL. Unlike the RT+STAD-NBF profile, the RT+LTAD-NBF profile rose continuously and steadily to a level approaching 1 ng/mL. The RT+LTAD-BF profile rose continuously but at a slower rate over time. Nine RT+STAD-NBF patients (22%) and 2 RT+LTAD-BF (29%) patients experienced 3 consecutive rises followed by a subsequent decline and stabilization of PSA compared to 10 RT-BF patients (5%). Redistributing these misclassified patients to their respective NBF groups changed the mean posttreatment PSA profiles as follows: The RT+LTAD-BF profile rose constantly and steadily with a doubling time of approximately 16 months, and the RT+LAD-NF initially rose to a value of approximately 0.5 ng/mL, then at 36 months began to decline.

CONCLUSIONS

The temporal kinetics of posttreatment PSA after RT+AD and RT alone are different. The American Society of Therapeutic Radiation Oncology definition for biochemical failure overestimates BF in 20-30% after RT+AD compared to 5% after RT alone.

Effectiveness of adjuvant intermittent endocrine therapy following neoadjuvant endocrine therapy and external beam radiation therapy in men with locally advanced prostate cancer

PURPOSE

To clarify the optimal duration and methods for adjuvant endocrine therapy after external beam radiation therapy (EBRT) in patients with locally advanced prostate cancer.

MATERIALS AND METHODS

Between 2001 and 2003, 215 patients with locally advanced prostate cancer were enrolled in the study. Patients were registered as primary candidates of the study and were treated with 6 months of LHRH agonist, with short-term of antiandrogen treatment for flare-up prevention. Patients with PSA levels below 10 ng/ml after the 6-month endocrine treatment were randomly divided into two arms. Then, a total dose of 72 Gy was given to the prostate. After 14 months of the protocol treatment, patients were treated with continuous androgen ablation (arm 1) or intermittent androgen ablation (arm 2).

RESULTS

A total of 188 cases (87%) remained in the protocol. The median PSA level at entry was 25.3 ng/ml. The Gleason score was 2-6 in 32 cases (16%), 7 in 94 cases (48%), and 8-10 in 68 cases (35%). The median PSA level showed a remarkable decrease to 1.1, 0.2, and 0.1 ng/ml, after 6, 8, and 14 months of the protocol treatment, respectively. Of the 157 cases treated with EBRT, 153 cases (97.5%) had no biochemical failure in the mean follow-up of 17.3 months.

CONCLUSIONS

The present study may reveal the possibilities of intermittent endocrine therapy after EBRT. However, the follow-up interval is short and little can be said about the results observed so far, exception of acute tolerance and patient acceptance of the protocol.

Definitions of biochemical failure that best predict clinical failure in patients with prostate cancer treated with external beam radiation alone: a multi-institutional pooled analysis

PURPOSE

Pooled data on 4,839 patients with T1-2 prostate cancer treated with external beam radiation therapy (RT) alone at 9 institutions have previously provided long-term biochemical failure (BF) and clinical outcomes using the American Society for Therapeutic Radiology and Oncology (ASTRO) definition. In this report we determined the sensitivity and specificity of several BF definitions using distant failure (DF) alone or clinical failure (CF), defined as local failure (LF) and/or DF.

MATERIALS AND METHODS

The pooled cohort was treated between 1986 and 1995 with external beam RT (60 Gy or greater) without pre-RT androgen suppression or planned post-RT adjuvant androgen suppression. Median followup was 6.3 years. The sensitivity and specificity of 102 definitions of BF relative to DF and LF were assessed.

RESULTS

The BF definitions with higher sensitivity and specificity than the ASTRO definition for DF only and CF are reported. The sensitivity and specificity of the ASTRO definition to predict DF alone was 55% and 68%, respectively. Three definitions had higher sensitivity and specificity, namely prostate specific antigen (PSA) greater than current nadir (lowest PSA prior to current measurement) plus 3 ng/ml (sensitivity 76% and specificity 72%), dated at the call (failure date as the date when the criterion was met), PSA greater than absolute nadir plus 2 ng/ml (sensitivity 72% and specificity 70%), dated at the call, or 2 consecutive increases of at least 0.5 ng/ml, back dated (sensitivity 69% and specificity 73%). The sensitivity and specificity of the ASTRO definition to predict CF was 60% and 72%, respectively. Three definitions had higher sensitivity and specificity, namely PSA greater than current nadir plus 3 ng/ml (sensitivity 66% and specificity 77%), dated at the call, PSA greater than absolute nadir plus 2 ng/ml (sensitivity 64% and specificity 74%), dated at the call, or 2 consecutive increases of at least 0.5 ng/ml, back dated (sensitivity 67% and specificity 78%).

CONCLUSIONS

Using what is to our knowledge the largest data set of patients with prostate cancer treated with RT alone we correlated multiple definitions of BF with the strict clinical end points of DF alone and CF (DF or local failure). Defining BF as PSA greater than absolute nadir plus 2 ng/ml, dated at the call, PSA greater than current nadir plus 3 ng/ml, dated at the call, or 2 consecutive increases of at least 0.5 ng/ml, back dated, had higher sensitivity and specificity for DF alone or CF compared with the ASTRO definition. This information should contribute to the discussion regarding suggested modifications to the ASTRO definition of biochemical failure.

Individualized predictions of disease progression following radiation therapy for prostate cancer

PURPOSE

Following treatment for localized prostate cancer, men are monitored with serial prostate-specific antigen (PSA) measurements. Refining the predictive value of post-treatment PSA determinations may add to clinical management, and we have developed a model that predicts future PSA values and the time to future clinical recurrence for individual patients.

PATIENTS AND METHODS

Data from 934 patients treated between 1987 and 2000 were used to develop a comprehensive statistical model to fit the clinical recurrence events and patterns of PSA data. A logistic model was used for the probability of cure, mixed models were used for serial PSA measurements, and a proportional hazards model was used for recurrences. Data available through February 2001 were fit to the model, and data collected between February 2001 and September 2003 were used for validation.

RESULTS

T-stage, baseline PSA, and radiotherapy dosage are all associated with probability of cure. The risk of clinical recurrence in those not cured is strongly affected by the slope of PSA values. We show how the model can be used for individual monitoring of disease progression. For each patient the model predicts, based on baseline characteristics and all post-treatment PSA values, the probability of future clinical recurrences and future PSA values. The model accurately predicts risk of recurrence and future PSA values in the validation data set.

CONCLUSION

This predictive information on future PSA values and the risk of clinical relapse for each individual patient, which can be updated with each additional PSA value, may prove useful to patients and physicians in determining post-treatment salvage strategies.

Prostate cancer progression after therapy of primary curative intent

BACKGROUND

Radical prostatectomy and radiotherapy (RT), both radical therapies, are the standard treatments of curative intent for early prostate cancer. However, these therapies are not curative in all patients and, consequently, a substantial proportion of treated patients remain at risk of disease progression and/or cancer-related death.

METHODS

This article presents contemporary data on the incidence of prostate-specific antigen (PSA) and clinical disease progression after primary therapy of curative intent in relation to commonly assessed pretreatment or pathologic disease characteristics.

RESULTS

The data highlight the substantial risk of progression for certain patient groups, such as those with Gleason score 8-10, cT3 disease, lymph node metastases, and/or pretreatment PSA levels > 20 ng/mL.

CONCLUSIONS

Improved and/or additional treatment options are needed for these patient groups.

Potential survival advantage with early androgen deprivation for biochemical failure after external beam radiotherapy: The importance of accurately defining biochemical disease status

PURPOSE

We analyzed our experience treating localized prostate cancer to determine the impact of androgen deprivation (AD) on clinical outcome if administered at the time of isolated biochemical failure (BF) vs. after clinical failure (clinical failure), and the associated impact of various BF definitions.

METHODS

A total of 1,201 patients with stage T1-T3N0M0 prostate cancer were treated with external beam radiotherapy (EBRT) to a median dose of 66.6 Gy. Early AD was defined as administration of AD after BF, without evidence of clinical failure. Delayed AD was defined as administration of AD after clinical failure. Multiple BF definitions were tested for capacity to predict subsequent clinical failure. For each BF definition, outcome was compared for BF patients receiving early AD vs. no or delayed AD.

RESULTS

Five-year clinical failure (from date of BF) was 60% for patients who experienced a prostate-specific antigen rise to >/=3 ng/mL above nadir. For these patients, early AD was associated with decreased 5-year local failure (4% vs. 33%), distant metastasis (13% vs. 44%), cause-specific death (9% vs. 24%), and death due to any cause (32% vs. 48%), despite poorer prognostic factors in patients receiving early AD. On multivariate analysis, early AD remained independently significant for each of these end points.

CONCLUSION

The efficacy of AD after BF varies depending on the BF definition. When an optimal BF definition is applied, early AD decreases distant metastasis and improves survival. Prostate-specific antigen elevation to >/=2 or >/=3 ng/mL above nadir seems optimal in establishing clinically significant BF and the timing of AD intervention.

Rise in serum psa of 1.5 ng/mL above 24-month nadir after external beam radiotherapy is predictive of biochemical failure

OBJECTIVES

To determine whether a rise in the serum prostate-specific antigen (PSA) concentration 24 months or later after completion of external beam radiotherapy (EBRT) for prostate cancer could predict for biochemical failure.

METHODS

We evaluated the records of 1006 patients who had undergone full-dose EBRT alone as primary treatment for T1-T4NxM0 prostate cancer at our institution between April 1987 and January 1998. Patients who had biochemical failure--as determined by the American Society for Therapeutic Radiology and Oncology (ASTRO) definition--prior to 24 months after EBRT were excluded. PSA increases of four different magnitudes (0.5, 0.8, 1.0, and 1.5 ng/mL above the 24-month nadir) were evaluated for their ability to predict ASTRO-defined biochemical failure.

RESULTS

A total of 745 patients met the analysis criteria. The rate of ASTRO-defined biochemical failure in patients with a PSA increase of 0.5, 0.8, 1.0, and 1.5 ng/mL above the 24-month nadir was 56%, 64%, 66%, and 71%, respectively. An increase of 1.5 ng/mL or more had a sensitivity of 80% and a specificity of 88% in the prediction of biochemical failure, with an accuracy of 86%.

CONCLUSIONS

A PSA increase of 1.5 ng/mL or more above the 24-month nadir can be used to predict for ASTRO-defined failure after EBRT and may be used to identify patients at risk early-on.

Neoadjuvant hormonal treatment and radiotherapy for prostate cancer

Adjuvant hormone treatment with radiotherapy has been demonstrated in two studies (Bolla and RTOG 8531) to be beneficial in patients with locally advanced prostate cancer. However, the vast majority of patients with early prostate cancer can be cured with radiotherapy alone. Subset analysis combining RTOG 8610 and RTOG 8531 has demonstrated a survival benefit only for patients with a biopsy Gleason score < or =6 after short-term neoadjuvant hormonal therapy. The results of ongoing research will further clarify the use of hormone treatment with radiotherapy in patients with low and intermediate risk.

Modifying the American Society for Therapeutic Radiology and Oncology definition of biochemical failure to minimize the influence of backdating in patients with prostate cancer treated with 3-dimensional conformal radiation therapy alone

PURPOSE

Adoption of the American Society for Therapeutic Radiology and Oncology (ASTRO) consensus definition has been critical for evaluating and comparing outcome following treatment with radiation. However, since its almost universal adoption, several points have remained controversial, notably backdating the date of failure to the point midway between the posttreatment prostate specific antigen (PSA) nadir and the first increase. We evaluated the impact of backdating on no biochemical evidence of disease (bNED) control and suggest changes in the definition.

MATERIALS AND METHODS

Between April 1, 1989 and November 30, 1998, 1,017 patients with nonmetastatic prostate cancer were treated with 3-dimensional conformal radiation therapy alone. bNED control was defined using the ASTRO consensus definition. bNED failure was calculated from the time midway between the posttreatment PSA nadir and the first of the 3 consecutive increases in PSA (date of failure A). Four alternate failure time points were chosen, including backdating to the date of the first increase in PSA after the nadir, the date between the first and second consecutive PSA increases, the date between the second and third consecutive PSA increases, and the date of the third increase in PSA after the nadir (dates of failure 1 to 4). Kaplan-Meier estimates were calculated for all definitions of failure as well as hazard functions with time. Subset analyses based on prognostic group and followup time were also performed.

RESULTS

The 10-year Kaplan-Meier bNED control rates were 64%, 52%, 47%, 42% and 39% using dates of failure A and 1 to 4, respectively. These differences persisted when patients were stratified by prognostic group. These same differences in bNED control were observed for the long-term followup subset, in which 10-year bNED control rates were 48%, 47%, 44%, 41% and 39% using dates of failure A and 1 to 4, respectively.

CONCLUSIONS

Adoption of the ASTRO consensus definition has been crucial for evaluating outcome in the radiation oncology community. However, the date of failure should be moved from the current point to one closer to the point at which failure is declared. Additional analysis with large numbers of patients from multiple institutions is necessary to determine the point.

Evidence for efficacy without increased toxicity of hypofractionated radiotherapy for prostate carcinoma: early results of a Phase III randomized trial

PURPOSE

We performed a randomized trial to compare the GI and urogenital toxicity of radiotherapy (RT) for localized (confined to the organ), early-stage (T1-T2N0M0, TNM classification) carcinoma of the prostate, using a conventional (64 Gy in 32 fractions within 6.5 weeks) vs. a hypofractionated (55 Gy in 20 fractions within 4 weeks) schedule and to determine the efficacy of the respective treatment schedules.

METHODS AND MATERIALS

This report is based on an interim analysis of the first 120 consecutive patients in this Phase III trial after a median follow-up of 43.5 months (range 23-62). RT planning was based on two-dimensional CT data, and the treatment was delivered using a three- or four-field 6-23-MV photon technique. GI and urogenital toxicity (symptom questionnaires incorporating the subjective elements of the late effects of normal tissues-subjective, objective, management, analytic classification of late effects and the European Organization for Research and Treatment of Cancer sexual function questionnaire) were evaluated before RT and 1 month, 1 year, and 2 years after RT completion. The efficacy of RT was assessed clinically (digital rectal examination and radiologic imaging) and biochemically (prostate-specific antigen assay) at baseline, and every 3 months for 2 years after RT and every 6 months subsequently.

RESULTS

RT, whether conventional or hypofractionated, resulted in an increase in all six symptom categories used to characterize GI toxicity and in four of five symptom categories used to document urinary morbidity 1 month after therapy completion. Sexual dysfunction (based on limited data), which existed in more than one-third of patients before RT, also increased to just more than one-half of patients 1 month after RT. The increase in urinary toxicity after RT was not sustained (diurnal urinary frequency had decreased significantly at 2 years). In contrast, all six symptom categories of GI toxicity remained increased 1 year after RT. Four of the six GI symptom categories (rectal pain, mucous discharge, urgency of defecation, and rectal bleeding) were still increased at 2 years compared with baseline. Except for a slightly greater percentage of patients experiencing mild rectal bleeding at 2 years among those who received hypofractionated RT, no differences were noted in toxicity between the conventional and hypofractionated RT schedule. The mean prostate-specific antigen level was 14.0 +/- 1.0 ng/mL at baseline and declined to a nadir of 1.3 +/- 0.2 ng/mL at a median of 16.8 months (range 0.8-28.3) after RT completion. However, it then rose in 17 patients (8 in the hypofractionated and 9 in the conventional treatment group). Only 8 of these 17 patients were found to have signs of clinical relapse (5 local, 1 regional lymph node, and 2 systemic [bony metastases]) after histopathologic and radiologic reassessment). The remaining 9 patients had biochemical relapse only (defined as three consecutive rises in prostate-specific antigen after nadir). The 4-year biochemical relapse-free survival rate was 85.8% for all patients and did not differ significantly between the two radiation dose schedules (86.2% for the hypofractionated and 85.5% for the conventional fractionation group).

CONCLUSION

RT for prostate carcinoma, using a three- or four-field 6-23-MV photon technique without posterior shielding of the lateral fields, is an underestimated cause of persistent GI morbidity. The incidence of clinically significant GI and urogenital toxicity after conventional and hypofractionated RT appears to be similar. Hypofractionated RT for carcinoma of the prostate seems just as effective as conventional RT after a median follow-up approaching 4 years.

Primary radiation therapy for localized prostate cancer

Prostate cancer in men is similar to breast cancer in women; both cancers rank first, respectively, in incidence and are normally responsive to radiation therapy. In addition, advances in mammography help detect earlier breast cancers, and the development and refinement of prostatic specific antigen (PSA) has resulted in early detection of low-stage localized prostate cancers. This has generated debate over the proper management of localized prostate cancer. While there have not been any controlled, prospective, randomized trials of sufficient power to compare the various local therapies, based on the current available data, the three commonly used local modalities, surgery, and external beam radiation therapy and brachytherapy (radioactive seed implant), have similar efficacy controlling the disease up to 10 years in many patients. Technological advances in treatment delivery and planning have improved the treatment of prostate cancer with external-beam radiotherapy using three-dimensional conformal radiotherapy (3DCRT), ultrasound-guided transperineal implant, or intensity-modulated radiotherapy (IMRT), as well as proton or neutron beam based therapies.

Practical application of biochemical failure definitions: what to do and when to do it

PURPOSE

The posttreatment prostate-specific antigen (PSA) profile can often be difficult to interpret after external beam radiotherapy for prostate cancer. We performed an extensive analysis of post-radiotherapy PSA measurements to determine the clinical significance of biochemical failure (BF) and the correlation of BF with clinical failure (CF) and cause-specific death (CSD).

MATERIALS AND METHODS

Between 1987 and 1997, 727 patients with clinical stage T1-T3 N0 M0 prostate cancer were treated with definitive external beam radiotherapy at William Beaumont Hospital and had at least five post-radiotherapy PSA levels and did not receive hormonal therapy for post-radiotherapy PSA elevations only (before evidence of CF). All patients received external beam radiotherapy alone (no adjuvant hormonal therapy) to a median total prostate dose of 66.6 Gy. More than 20 BF definitions were tested for their correlation with CF (any local failure or distant metastasis) and CSD. All BF definitions were tested for sensitivity, specificity, accuracy, and positive and negative value of predicting subsequent CF and CSD. The median follow-up was 5.0 years.

RESULTS

Three consecutive PSA rises yielded a 73% sensitivity, 76% specificity, and 75% overall accuracy for predicting CF. The 10-year CF rate (from the completion of radiotherapy) for those 251 patients demonstrating three consecutive rises (BF) was 64% vs. 14% for those patients who did not have three rises (biochemically controlled). Defining BF as a post-nadir increase to >or=3 ng/ml above the nadir yielded the highest accuracy of 87%. In addition, this definition also seemed to provide the greatest separation in CF rates: 82% for BF vs. 5% for biochemically controlled at 10 years after radiotherapy. CF rates were also calculated from the date of BF (e.g., date of third rise). The CF rates at 6 months and 2 years after the third PSA rise were 9% and 27%, respectively. The CF rates at 6 months and 2 years after an increase to >or=3 ng/ml above the nadir were 23% and 54%, respectively. Once a patient was classified as a BF, regardless of the BF definition, the CF rate varied markedly, depending on the pretreatment characteristics. For each BF definition, younger age at diagnosis, higher pretreatment PSA, and higher Gleason score independently predicted for CF after BF on Cox multiple regression analysis. For instance, patients with a pretreatment PSA <4.0 ng/ml demonstrated an 11% CF rate at 2 years after the third PSA rise vs. 46% after three rises with a pretreatment PSA >or=20.0 ng/ml. Similarly, patients with Gleason 2-4 had a 2-year CF rate of only 3% after a nadir >or=1.0 ng/ml vs. 47% for Gleason 8-10 at 2 years after a nadir >or=1.0 ng/ml. Although the CF rate also coincided with pretreatment characteristics when using >or=3 ng/ml above the nadir, CF rates remained high even for low-risk patients (e.g., 2-year CF of 48% for PSA <10.0 ng/ml, 41% for Gleason 2-4). In addition, a shorter time interval from nadir to nadir + 1 ng/ml or from nadir to nadir + 3 ng/ml (corresponding to a steeper slope in the PSA profile) independently predicted for CF.

CONCLUSION

Once the post-radiotherapy PSA profile reaches >or=3 ng/ml above the nadir, there is a high risk of clinical failure within a relatively short time period, for which treatment intervention may be considered, regardless of pretreatment characteristics. After a nadir >or=1.0 ng/ml or three consecutive rises, some patients (especially with low-risk pretreatment characteristics) may be considered for further PSA observation before treatment intervention.

[Clinical and biological surveillance after radiotherapy for localized prostate cancer]

Serum PSA is an excellent marker of disease status after external beam radiotherapy or brachytherapy for patients with prostate carcinoma. A low PSA nadir < or = 1 even < or = 0.5 ng/mL has been shown to be as a surrogate end point for disease control. Three successive increases of this marker after achieving the nadir defines recurrence as recommended by the American Society for Therapeutic Radiology and Oncology. The biochemical relapse or PSA failure after treatment precedes clinical disease relapse by several months. PSA profile or kinetics may have implications for patterns of failure and prognosis. Prostate post-radiotherapy biopsies should not be part of routine follow-up as its interpretation is frequently problematic. Other exams should not be performed unless clinical symptoms are present. Post-radiotherapy relapse treatment has generally no curative intent.

Postoperative radiotherapy for carcinoma of the prostate: impact on both local control and distant disease-free survival

The role of postoperative irradiation in patients with clinically localized prostate cancer, either as an adjuvant or salvage radiotherapy, remains controversial. In this study, we evaluate the impact of postoperative radiotherapy on patients diagnosed with prostate cancer with respect to biochemical and clinical disease free survival. Between 1987 and 1996, 179 patients with clinically localized prostate cancer were found to have adverse histopathologic findings on radical prostatectomy specimens (positive surgical margins, extracapsular extension, and seminal vesicle invasion). Of these patients, 42 were referred for postoperative adjuvant radiotherapy, whereas 73 were referred for salvage irradiation because of rising serum prostate-specific antigen (PSA) levels postoperatively. The remaining 64 patients underwent prostatectomy only. The 10-year biochemical relapse-free survival (RFS) from date of surgery were 88%, 45%, and 25% for patients treated with postoperative adjuvant radiotherapy, salvage irradiation, and with surgery alone, respectively (p = 0.046). Ten-year distant RFS from date of surgery were 82%, 74%, and 44% for adjuvantly treated patients, those with salvage radiotherapy, and those with surgery alone, respectively (p = 0.0180). Ten-year overall disease RFS from date of surgery was 89%, 76%, and 30% for adjuvantly treated patients, those with salvage radiotherapy, and those with surgery alone, respectively (p = 0.0237). Multivariate analyses revealed that a preoperative PSA greater than 20 ng/ml and pathologic Gleason Score of 8 to 10 were adverse predictors for biochemical relapse, whereas pathologic Gleason Score of 8 to 10, seminal vesicle invasion, and extracapsular extension were adverse predictors of distant metastases. Postoperative radiotherapy, either delivered as adjuvant treatment for adverse histopathologic findings or as salvage therapy for local relapses, appear to confer superior local, distant disease RFS, and overall disease RFS than surgery alone.

Definitions of biochemical failure in prostate cancer following radiation therapy

PURPOSE

The American Society for Therapeutic Radiology and Oncology (ASTRO) published a consensus panel definition of biochemical failure following radiation therapy for prostate cancer. In this paper, we develop a series of alternative definitions of biochemical failure. Using data from 688 patients, we evaluated the sensitivity and specificity of the various definitions, with respect to a defined "clinically meaningful" outcome.

METHODS AND MATERIALS

The ASTRO definition of biochemical failure requires 3 consecutive rises in prostate-specific antigen (PSA). We considered several modifications to the standard definition: to require PSA rises of a certain magnitude, to consider 2 instead of 3 rises, to require the final PSA value to be greater than a fixed cutoff level, and to define biochemical failure based on the slope of PSA over 1, 1.5, or 2 years. A clinically meaningful failure is defined as local recurrence, distant metastases, initiation of unplanned hormonal therapy, unplanned radical prostatectomy, or a PSA > 25 later than 6 months after radiation.

RESULTS

Requiring the final PSA in a series of consecutive rises to be larger than 1.5 ng/mL increased the specificity of biochemical failure. For a fixed specificity, defining biochemical failure based on 2 consecutive rises, or the slope over the last year, could increase the sensitivity by up to approximately 20%, compared to the ASTRO definition. Using a rule based on the slope over the previous year or 2 rises leads to a slightly earlier detection of biochemical failure than does the ASTRO definition. Even with the best rule, only approximately 20% of true failures are biochemically detected more than 1 year before the clinically meaningful event time.

CONCLUSION

There is potential for improvement in the ASTRO consensus definition of biochemical failure. Further research is needed, in studies with long follow-up times, to evaluate the relationship between various definitions of biochemical failure and true clinical outcome.

The impact of irregularly rising prostate-specific antigen and "impending failure" on the apparent outcome of localized prostate cancer following radiotherapy

PURPOSE

To examine the impact of irregularly rising prostate-specific antigen (PSA) and "impending" biochemical failure on the apparent rate of biochemical relapse following radiotherapy for localized prostate cancer.

METHODS AND MATERIALS

We analyzed the outcome of 572 patients with T1/T2 prostate cancer treated with radiotherapy alone at the Princess Margaret Hospital (median follow-up, 4.21 years). Biochemical outcomes were analyzed using 2 different definitions of failure: (1) the American Society for Therapeutic Radiology and Oncology (ASTRO) definition, and (2) a modified definition that included 2 consecutive rises in PSA, with a minimum rise of 1.5 ng/mL above the nadir, or a nadir value of greater than 4 ng/mL. Patients were defined as having "impending failure" when the last 2 PSA measurements taken demonstrated 2 consecutive rises.

RESULTS

Two-hundred and thirty patients (40%) met the ASTRO definition of failure; 258 patients (48%) failed by the modified definition (p = 0.001). Five-year biochemical relapse-free rate (bNED) rate was 55% using the ASTRO definition, and 49% using the modified definition. This difference in 5-year bNED was greatest for patients with high-risk disease (ASTRO definition 30% vs. modified definition 15%). Twenty-four of the 38 additional cases identified as biochemical failures by the modified definition had irregularly rising PSA levels; 14 were "impending failures." These additional 38 patients had a median PSA elevation 5.4 ng/mL above the nadir, and a high risk of subsequent clinical failure (4-year clinical failure-free rate of 63%). The ASTRO definition had a sensitivity of 87% and specificity of 74% for predicting clinical relapse. The modified definition had a sensitivity of 95% and a specificity of 70%.

CONCLUSION

A definition of biochemical failure that includes an absolute allowable rise in PSA above the nadir can identify patients with rising PSA who are at substantial risk of clinical relapse, but who are not defined as biochemical failures by the ASTRO definition. This is particularly true for patients with high-risk disease. The use of a uniform definition of biochemical failure is crucial to ensure that differences in apparent outcome are not due to differences in the definition of relapse. Currently, the ASTRO definition should remain the standard. Large cohort studies with long follow-up can be utilized to optimize the definition of biochemical failure following radiotherapy for prostate cancer.

Prognostic value of neuroendocrine serum markers and PSA in irradiated patients with pN0 localized prostate cancer

BACKGROUND

The prognosis of patients with localized prostate cancer depends on clinical stage, histological grade, and pretreatment prostate-specific antigen (PSA). We evaluated the additional prognostic impact of serum levels of neuron-specific enolase (NSE) and chromograninA (CgA) after curative radiotherapy and the importance of serum PSA, analyzed 3 months after irradiation.

METHODS

From 1988 to 1995, 161 patients with localized T1-4, pN0M0, prostate adenocarcinoma were treated with external radiation (66Gy, 2Gy/5 fractions per week). Frozen serum samples were assessed for CgA, NSE, and PSA before and 3 months after radiotherapy. CgA was analyzed in only 100 patients. NSE and CgA were determined by a immunometric assay. Total PSA was measured by a time-resolved fluoro-immunometric assay.

RESULTS

Prior to radiotherapy CgA was elevated in 16 of 100 patients, and NSE was elevated in 33 of the 161 patients. There was no association between grade, T category or pretreatment PSA and the levels of neuroendocrine markers. Pretreatment-elevated serum NSE, but not initial CgA, identified patients with an unfavorable prognosis. A < 50% reduction of PSA 3 months after radiotherapy was associated with decreased failure-free 10 years urvival. Multivariate analysis demonstrated an increased risk of failure for patients with elevated pretreatment NSE and PSA values, T3 category, and decline of PSA less than 50% 3 months after radiotherapy. The presence of none or several risk factors (1-4) defined clearly separable groups.

CONCLUSIONS

Together with T category and pretreatment serum PSA values, serum NSE values before radiotherapy and decrease of serum PSA 3 months after radiotherapy represent easily assessable prognostic parameters in patients undergoing curative radiation treatment for prostate cancer.

Is there a subset of patients with PSA > or = 20 ng/ml who do well after conformal beam radiotherapy?

To determine if there is a subgroup of patients with pretreatment PSA > or = 20 ng/ml with a favorable outcome after external beam radiation therapy. We analyzed retrospectively treatment outcomes of 129 patients with pretreatment PSA > or = 20 ng/ml treated in our department from 2/88-8/94. Median patient age was 70 years (range 51-89 years). Tumor stage was T1/T2ab in 68, T2c/T3 in 61 patients. Initial Gleason grade was < 7 in 82 and > or = 7 in 47 patients. Median PSA was 35 ng/ml (mean 45 ng/ml, range 20-191 ng/ml). Ninety-seven patients received four-field conformal external beam radiation therapy. No patient received surgery or hormonal therapy prior to treatment. Median central axis dose was 73 Gy (range 68-79 Gy). Covariates considered in univariate and multivariate analyses included central axis dose, pretreatment PSA, presence of perineural invasion, Gleason score, palpable tumor stage and patient age. bNED failure was defined as a PSA > or = 1.5 and rising on two consecutive determinations. Median follow up was 50 months (range 3-100 months). Overall bNED control for the entire patient population was 22% at five years. Of the covariates analyzed, dose (P < 0.01), stage (P < 0.01), Gleason Score (P < 0.01), and the presence of PNI (P = 0.01) were significant on multivariate analysis. Based on these results, patients could be stratified into two distinct groups. Group I consisted of 19 patients with favorable features including T1/T2ab disease, Gleason Score 2-6, no perineural invasion treated to a dose > 73 Gy to the central axis. Patients in Group II had at least one of the above poor prognostic features or were treated to central axis doses < 73 Gy. The bNED control was significantly higher for patients in Group I than those in Group II (58% vs. 23%, P = 0.0027). There appears to be a favorable subgroup of patients with PSA > or = 20 ng/ml where treating to doses over 73 Gy to the central axis is warranted (four-year bNED rate of 58%). However, because of the small patient numbers, these results will need to be validated with longer follow up.

Matched-pair analysis of conformal high-dose-rate brachytherapy boost versus external-beam radiation therapy alone for locally advanced prostate cancer

PURPOSE

We performed a matched-pair analysis to compare our institution's experience in treating locally advanced prostate cancer with external-beam radiation therapy (EBRT) alone to EBRT in combination with conformal interstitial high-dose-rate (HDR) brachytherapy boosts (EBRT + HDR).

MATERIALS AND METHODS

From 1991 to 1998, 161 patients with locally advanced prostate cancer were prospectively treated with EBRT + HDR at William Beaumont Hospital, Royal Oak, Michigan. Patients with any of the following characteristics were eligible for study entry: pretreatment prostate-specific antigen (PSA) level of >/= 10.0 ng/mL, Gleason score >/= 7, or clinical stage T2b to T3c. Pelvic EBRT (46.0 Gy) was supplemented with three (1991 through 1995) or two (1995 through 1998) ultrasound-guided transperineal interstitial iridium-192 HDR implants. The brachytherapy dose was escalated from 5.50 to 10.50 Gy per implant. Each of the 161 EBRT + HDR patients was randomly matched with a unique EBRT-alone patient. Patients were matched according to PSA level, Gleason score, T stage, and follow-up duration. The median PSA follow-up was 2.5 years for both EBRT + HDR and EBRT alone.

RESULTS

EBRT + HDR patients demonstrated significantly lower PSA nadir levels (median, 0.4 ng/mL) compared with those receiving EBRT alone (median, 1.1 ng/mL). The 5-year biochemical control rates for EBRT + HDR versus EBRT-alone patients were 67% versus 44%, respectively (P <.001). On multivariate analyses, pretreatment PSA, Gleason score, T stage, and the use of EBRT alone were significantly associated with biochemical failure. Those patients in both treatment groups who experienced biochemical failure had a lower 5-year cause-specific survival rate than patients who were biochemically controlled (84% v 100%; P <.001).

CONCLUSION

Locally advanced prostate cancer patients treated with EBRT + HDR demonstrate improved biochemical control compared with those who are treated with conventional doses of EBRT alone.

The correlation of serial prostate specific antigen measurements with clinical outcome after external beam radiation therapy of patients for prostate carcinoma

BACKGROUND

The authors analyzed retrospectively their institution's experience in treating patients with localized prostate carcinoma with external beam radiation therapy (EBRT) to determine the correlation of various biochemical failure (BF) definitions with clinical failure and cause specific survival (CSS).

METHODS

Between January 1987 and December 1997, 1,094 patients with clinical T1-T3N0M0 prostate carcinoma were treated with definitive EBRT alone at William Beaumont Hospital, Royal Oak, Michigan. All patients received EBRT alone (no adjuvant hormones) to a median total prostate dose of 66.6 grays (Gy) (range, 59.4-70.4 Gy). Multiple BF definitions were tested for their correlation with clinical failure and cause specific death (CSD = 1-CSS). All BF definitions were tested for sensitivity, specificity, and accuracy of predicting subsequent clinical failure and CSD. Positive and negative predictive values were calculated in the form of 10-year actuarial clinical failure and CSD rates. Analyses were performed on all 1,094 patients as well as for those 727 patients who had at least 5 post-RT prostate specific antigen (PSA) level measurements and who did not receive hormonal therapy for post-RT PSA elevations. The median PSA follow-up was 4.0 years for the entire population and 4.5 years for those 727 patients included in the second analysis.

RESULTS

In the entire population, 167 patients (15%) experienced clinical failure corresponding to 5- and 10-year actuarial rates of 16% and 34%, respectively. The correlation of various BF definitions with outcome was calculated in those 727 patients who did not receive hormonal therapy. For these patients, BF (as defined by the American Society for Therapeutic Radiology and Oncology Consensus Panel) yielded a 73% sensitivity, 76% specificity, and 75% overall accuracy for predicting clinical failure and a 74% sensitivity, 69% specificity, and 69% overall accuracy for predicting CSD. The 10-year clinical failure rate for those 251 patients demonstrating 3 consecutive PSA rises (BF) was 64% versus 14% for those patients who did not meet these criteria (biochemically controlled [BC]). As expected, definitions requiring only two rises were more sensitive but less specific in predicting clinical failure than those definitions requiring three or four rises. Because there were dramatically more clinically controlled patients (85%) than clinical failures (15%), the overall accuracy for each definition more closely approximated its specificity. The definitions classifying BF as a postnadir increase of > or = 3 or > or = 4 ng/mL above the nadir yielded the highest accuracies of 87% and 88%, respectively. In addition, these definitions also appeared to provide the greatest separation in clinical failure rates between BC and BF patients, an absolute difference of 77% and 76%, respectively.

CONCLUSIONS

The correlation between BF and clinical failure and CSD varies markedly depending on the BF definition used. Definitions incorporating a fixed baseline (the nadir level) and the postnadir PSA profile may have better correlation with clinical failure than definitions using the nadir only or a specific number of consecutive rises in which a variable baseline "resets" after a PSA decrease.

Scrutiny of the ASTRO consensus definition of biochemical failure in irradiated prostate cancer patients demonstrates its usefulness and robustness. American Society for Therapeutic Radiology and Oncology

PURPOSE

The goals of this study are: (1) to establish the robustness of the Fox Chase Cancer Center (FCCC) and the American Society for Therapeutic Radiology and Oncology (ASTRO) consensus definitions of failure by comparing biochemical estimates under various modifications of the censoring and failure time components to their respective unaltered definitions; (2) to isolate the source of variation between the two definitions of failure; and (3) to describe the hazard of failure over time for each definition.

METHODS

Between May 1989 and May 1997, 670 men were treated at Fox Chase Cancer Center for localized prostate cancer using three-dimensional conformal radiation therapy (3DCRT). These men were stratified into three groups for analysis: 111 men treated with adjuvant hormones; 204 men treated with radiation therapy alone and presenting with more favorable prognosis tumor characteristics; 255 men treated with radiation therapy alone and presenting with less favorable prognosis tumor characteristics. For each group, biochemical failure was estimated and compared using the FCCC and ASTRO definitions of failure. The robustness of each definition was evaluated by comparing estimates under the definition as stated to those under various modifications of the censoring and failure components. Analyses were also performed while excluding slow-progressing patients. To isolate the source of variation between the two failure definitions, estimates were compared for patients with agreement in failure status. Estimates of biochemical failure, and thus hazard rates, were made using Kaplan-Meier methodology.

RESULTS

ASTRO biochemical failure estimates were higher than the FCCC failure estimates in the first 5 years post-treatment. Beyond 5 years, ASTRO estimates level off, while the FCCC failure estimates continued to increase. These failure patterns were similar in all patient groups; however, patients treated with adjuvant hormones had a much higher risk of failure immediately following treatment under the ASTRO definition. Modifying the censoring pattern had little effect on failure estimates in any patient group, regardless of definition used. The exclusion of patients with slow prostate-specific antigen (PSA) doubling time did not result in biochemical estimates that differed significantly from those for all patients. The analysis of patients with agreement in failure status continued to demonstrate significant differences in estimates between the two definitions, and thus differences may be attributed to the specification of time to failure. For all patient groups, hazard rates were dependent upon failure definition: under the FCCC failure definition, patients were at constant risk of failure over the observation period; under the ASTRO failure definition, patients were at risk of failure during the first 4 years following treatment, and then at low risk of failure beyond 5 years.

CONCLUSIONS

Both FCCC and ASTRO failure definitions were robust to modifications in censoring and the inclusion of patients with long doubling times. The ASTRO failure definition was robust to specifying the time to failure at first rise, as opposed to midway between nadir and first rise. Similarities in estimates for all patients versus patients with agreeing failure status suggest that differences in failure definition lie in the specification of time to failure. The ASTRO definition of failure is more appropriate because it does not impose an empirical failure marker but is based on the initiation of biochemical rise. The use of the ASTRO consensus definition demonstrated little risk of biochemical failure 4 years beyond treatment. The ASTRO failure definition should be adopted in all research involving biochemical failure analysis of men treated with radiation therapy.

A comparison of external beam radiation therapy versus radical prostatectomy for patients with low risk prostate carcinoma diagnosed, staged, and treated at a single institution

BACKGROUND

The authors retrospectively reviewed their institution's long term experience treating a group of comparably staged low risk prostate carcinoma patients with either radical prostatectomy or external beam radiation therapy (RT) to determine whether the method of treatment resulted in significant differences in biochemical control and/or survival.

METHODS

From January of 1987 through December of 1994, 382 patients (157 who underwent radical prostatectomy and 225 who received external beam RT) were treated with curative intent for localized prostate carcinoma at William Beaumont Hospital. All patients had a pretreatment serum prostate specific antigen (PSA) level < or =10.0 ng/mL and a biopsy Gleason score </=6. Patients treated with RT received a median dose of 66.6 gray (Gy) (range, 59.2-70.2 Gy) to the prostate. Patients treated surgically underwent radical retropubic prostatectomy with a pelvic lymph node dissection. For surgical patients, biochemical failure was defined as a detectable PSA level > or =0.2 ng/mL at any time after prostatectomy. For RT patients, biochemical failure was defined according to the American Society for Therapeutic Radiology and Oncology Consensus Panel definition. Pretreatment PSA levels and Gleason scores were not significantly different between patients treated with radical prostatectomy or RT. The median follow-up in each treatment group was 5.5 years.

RESULTS

The 7-year actuarial rates of biochemical control and cause specific survival were not significantly different between patients treated either with radical prostatectomy or RT (67% vs. 69% for biochemical control and 99% vs. 97% for cause specific survival, respectively). A number of clinical, pathologic, and treatment-related factors were analyzed for an association with biochemical failure (i.e., age, pretreatment PSA, Gleason score, and treatment modality). Only pretreatment PSA and Gleason score were significantly related to outcome in both univariate and multivariate analyses.

CONCLUSIONS

Low risk prostate carcinoma patients with similar pretreatment PSA levels and biopsy Gleason scores treated at the same institution with either radical prostatectomy or RT achieved similar 7-year rates of biochemical control and cause specific survival, regardless of treatment technique. These findings suggest that for patients with pretreatment PSA levels </=10 ng/mL and Gleason scores </=6, conventional doses of external beam RT and radical retropubic prostatectomy can be expected to produce comparable treatment results unaffected by age at diagnosis.

The cost effectiveness of 3D conformal radiation therapy compared with conventional techniques for patients with clinically localized prostate cancer

BACKGROUND

We previously demonstrated the advantages of three-dimensional conformal radiation therapy (3DCRT) in improved rates of biochemical (bNED) control in certain subsets of patients with clinically localized prostate cancer. However, in this era of cost consciousness and limited resources, the cost effectiveness of 3DCRT compared with conventional external beam irradiation (CRT) remains unexamined.

METHODS AND MATERIALS

Between October 1, 1987 and November 30, 1991, 193 patients with clinically localized prostate cancer received definitive external beam irradiation at Fox Chase Cancer Center. The 1998 Medicare fee schedule was used to determine treatment charges and to provide a reference for a national comparison. Complete charges for pretreatment work-up, treatment, and follow-up were tabulated for each patient. The mean total charges (MTC) using the Lin method of estimating medical costs was used to analyze and compare costs between groups. A matched case/control analysis was performed to further evaluate the effect of cost between techniques. The median follow-up was 72 months (range 3-118).

RESULTS

The overall 5-year actuarial rate of bNED control was 41% and 53%, respectively, for the CRT and 3DCRT patients (p = 0.03). The MTC for the CRT patients was $10,544.53. For the 3DCRT patients, the MTC was $8,955.48. The sample mean of the total costs from the observed deaths for the two patient groups by follow-up interval ranged from $9,800.63 to $59,635.01 for the CRT patients to $17,259.00 to $24,250.38 for the 3DCRT patients. No statistically significant difference in cost was observed between groups using the matched case/control analysis.

CONCLUSION

Initial work-up and treatment costs were greater for patients treated with 3DCRT compared with patients treated with conventional techniques. However, with longer follow-up, the mean total cost of treatment was not statistically different between the two treatment groups. Because of improved rates of bNED control for these patients and the increased costs associated with the treatment of a greater fraction of patients with recurrent disease following CRT, 3DCRT was cost effective for patients with clinically localized prostate cancer.

Defining biochemical cure for prostate carcinoma patients treated with external beam radiation therapy

BACKGROUND

The authors retrospectively reviewed their institution's long term experience with conventional external beam radiation therapy (RT) for localized prostate carcinoma to identify criteria associated with long term biochemical cure.

METHODS

Between January 1987 and December 1994, 871 patients were treated with external beam RT alone for clinically localized prostate carcinoma at William Beaumont Hospital, Royal Oak, Michigan. All patients received only external beam RT to a median total dose of 66.6 grays (Gy) (range, 59.4-70.4 Gy). No patient received hormonal therapy unless treatment failure was documented. The median follow-up was 5.0 years (range, 0. 2-11.8 years). Biochemical failure was defined according to the American Society for Therapeutic Radiology and Oncology Consensus Panel definition.

RESULTS

In the entire study group, 380 patients experienced biochemical failure at a median interval of 1.5 years after the completion of RT. The 5-year and 7-year actuarial rates of biochemical control were 50% and 48%, respectively. On multivariate analysis, a higher pretreatment prostate specific antigen (PSA) level, higher Gleason score, higher clinical T classification, higher nadir level, and shorter time interval to nadir all were associated significantly with biochemical failure (P < 0.001). The median intervals to biochemical failure for patients with pretreatment PSA levels </= 3.9 ng/mL, 4.0-19.9 ng/mL, and >/= 20.0 ng/mL were 2.2 years, 1.5 years, and 1.2 years, respectively (P < 0. 001). The median intervals to biochemical failure for patients with Gleason scores of 2-4, 5-7, and 8-10 were 1.8 years, 1.5 years, and 1.1 years, respectively (P < 0.001). Only 6 patients failed beyond 5 years after treatment even though 136 patients were at risk for failure beyond this point. When restricting analysis to 643 patients (74%) with >/= 3 years of PSA follow-up, the median nadir level for biochemically controlled patients was 0.6 ng/mL and occurred at a median interval of 1.9 years after RT versus a median nadir level of 1.3 ng/mL (P = 0.002) occurring at a median interval of 1.0 years (P < 0.001) in those patients who experienced biochemical failure. Patients were divided into subgroups based on their PSA nadir level and time to nadir. The 5-year actuarial biochemical control rates for patients with nadir values of </= 0.4 ng/mL, 0.5-0.9 ng/mL, 1. 0-1.9 ng/mL, 2.0-3.9 ng/mL, and >/= 4.0 ng/mL were 78%, 60%, 50%, 20%, and 9%, respectively (P < 0.001). The 5-year actuarial biochemical control rates for patients who reached their nadir at < 1.0 years, 1.0-1.9 years, 2.0-2.9 years, and >/= 3.0 years were 30%, 52%, 64%, and 92%, respectively (P < 0.001). All 52 patients who achieved a nadir of </= 0.4 ng/mL and required >/= 2.0 years to reach this nadir had biochemically controlled disease.

CONCLUSIONS

These results suggest that a patient has a high likelihood of biochemical cure after treatment for prostate carcinoma with conventional doses of external beam RT if he has not demonstrated biochemical failure within 5 years of treatment. Patients with lower pretreatment PSA levels and lower Gleason scores may require longer follow-up than those with less favorable characteristics to achieve the same certainty of cure. Patients who achieve a PSA nadir </= 0.4 ng/mL and require >/= 2.0 years to reach this nadir have the highest probability of cure.

The importance of adequate follow-up in defining treatment success after external beam irradiation for prostate cancer

PURPOSE

We reviewed our institution's experience treating patients with localized prostate cancer with external beam radiation therapy (RT) to determine how differences in the length of follow-up affect the determination of treatment outcome using the American Society for Therapeutic Radiology and Oncology (ASTRO) Consensus Panel Definition of biochemical failure (BF).

METHODS AND MATERIALS

From January 1987 through December 1997, 1109 patients with localized prostate cancer were treated with definitive external beam RT at William Beaumont Hospital, Royal Oak, Michigan. All patients received external beam RT to a median total prostate dose of 66.6 Gy (range: 59.4-70.4 Gy). A total of 1096 patients (99%) had sufficient prostate-specific antigen (PSA) follow-up to determine their biochemical status. To test the impact of differences in follow-up on the calculation of BF, 389 patients with at least 5 years of PSA follow-up were selected as the reference group for the initial analysis. BF was then retrospectively determined using the Consensus Panel definition at yearly intervals, ignoring the remainder of each patient's follow-up. The median follow-up for this group of patients was 6.6 years (range: 5.0-11.6 years). In a second analysis, patient cohorts were randomly selected with varying median PSA follow-up intervals in order to more accurately represent a population whose follow-up is distributed continuously over a defined range. Seven cohorts were randomly selected with 200 patients in each cohort. Cohorts were individually identified such that half of the patients (100) had 2 years or less follow-up than the stated time point for analysis and half (100) had up to 2 years more follow-up than the time point chosen for analysis. For example, in the cohort with a median follow-up of 3 years, 100 patients with a PSA follow-up from 1 to 3 years were randomly selected, and 100 patients with a follow-up from 3 to 5 years were randomly selected, thus generating a median follow-up of 3 years for this cohort (range: 1 to 5 years). This process was repeated five times for five random samples of seven cohorts each. Biochemical failure was calculated according to the Consensus Panel definition.

RESULTS

In the first analysis, significantly different rates of biochemical control (varying by 6-21%) were calculated for the same actuarial year chosen for analysis depending only upon the length of follow-up used. For example, the 3-year actuarial rate of biochemical control (BC) varied from 71% when calculated with 3 years of follow-up versus 50.4% with 7 years (p < 0.01). These differences in actuarial rates of BC were observed in all subsets of patients analyzed (e.g., PSA < 10, Gleason < or = 6, n = 132,p < 0.001; PSA < 10, Gleason > or = 7, n = 33, p = 0.03; PSA > or = 10, Gleason < or = 6, n = 109, p < 0.001; and PSA > or = 10, Gleason > or = 7, n = 72, p = 0.002). The absolute magnitude of the difference in actuarial rates of BC was greatest during years 2 (range 18-30%), 3 (range 16-25%), and 4 (range 15-24%) after treatment. In the second analysis using median PSA follow-ups (as defined above), statistically significant differences in actuarial rates of BC were again observed. For example, the 3-year actuarial rate of BC varied from 74.8% with a median follow-up of 2 years versus 49.2% with a median follow-up of 6 years. These dramatic differences in BC were still observed beyond 5 years.

CONCLUSION

When the ASTRO Consensus Panel definition of BF is used to calculate treatment success with external beam RT for prostate cancer, adequate follow-up is critical. Depending upon the length of time after treatment, significantly different rates of BC (varying by 15% to 30%) can be calculated for the same time interval chosen for analysis. These results suggest that data should only be reported if the length of follow-up extends at least beyond the time point at which actuarial results are examined for the majority of patients.

PSA-based outcome analysis after radiation therapy for prostate cancer: a new definition of biochemical failure after intervention

OBJECTIVES

To examine pretreatment variables that influence biochemical failure, and to describe and test a new definition of prostate-specific antigen (PSA)-based biochemical failure.

METHODS

We introduce and describe a new definition of biochemical failure, which is based on quadratic fitting of the logarithm of the follow-up PSA profile curve. From a data base of 449 patients with prostate cancer treated with definitive radiation therapy, 230 patients who had at least five follow-up PSA observations were chosen for analysis. The new definition of failure was applied to this cohort, as was the conventional definition of two consecutive PSA rises. Univariate and multivariate analyses were performed using established pretreatment prognostic factors as covariates. Also, the association of both definitions of failure with clinical outcome (local recurrence and any recurrence) was examined.

RESULTS

Application of the new definition of biochemical failure resulted in smoothing of the "noise" that is inherent in using definitions based on successive PSA rises. This smoothing was verified by smaller P values for the statistically significant covariates in the univariate analysis. Furthermore, the new definition correlated better with clinical outcome, as demonstrated by the statistically significant P values on regression analysis when using the quadratic fitted nadir compared with using the observed nadir.

CONCLUSIONS

We devised a new criterion based on quadratic curve fitting for PSA-based biochemical failure. This definition is based on all available PSA information, correlates with both pretreatment factors and post-treatment clinical outcome, is relatively insensitive to noise, and allows for prediction of time of failure.

Is there a role for short-term hormone use in the treatment of nonmetastatic prostate cancer?

We reviewed our institution's experience treating patients with prostate cancer with 3-dimensional conformal radiation therapy (3DCRT) and short-term adjuvant hormonal therapy to determine biochemical no evidence of disease (bNED) and clinical outcome compared with patients treated with 3DCRT alone. Between 4/1/89 and 11/30/94, 558 patients with clinically localized prostate cancer received treatment at Fox Chase Cancer Center (Philadelphia, Pa.); 484 patients were treated with 3DCRT alone (Group I); 74 patients were treated with 3DCRT and hormones (Group II). Five-year actuarial rates of bNED control, distant metastasis-free survival (DMFS), cause-specific survival (CSS), and overall survival (OS) were calculated for pretreatment PSA, Gleason score, T stage, use of hormones, treatment field size, age, and dose. A matched case/control analysis was performed to further evaluate the effect of hormones on treatment with 3DCRT. Median follow-up was 47 months (range: 2-97 months). The 5-year actuarial rates of bNED control, DMFS, CSS, and OS were 66%, 93%, 98%, and 86%, respectively, for Group I patients and 68%, 93%, 98%, and 89%, respectively, for Group II patients. Multivariate analysis demonstrated that hormone use was an independent predictor of bNED control only. A significant difference in bNED control was observed between Group I and II (43% vs. 71%) using the matched case/control analysis (P = 0.02). A trend towards significance was observed for different rates of DMFS between Group I and II (79% vs. 94%, P = 0.09). Patients with clinically localized prostate cancer with poor prognostic features (pretreatment PSA > or = 10 ng/ml, Gleason score > or = 7, and/or T2c or greater palpation stage) show improved rates of bNED control and a trend towards improved DMFS when treated with 3DCRT and short-term adjuvant hormones compared with 3DCRT alone. Long-term observation will be necessary to see if improvements in bNED control will translate into improvements in overall survival.

A comprehensive review of prostate cancer brachytherapy: defining an optimal technique

PURPOSE

A comprehensive review of prostate cancer brachytherapy literature was performed to determine if an optimal method of implantation could be identified, and to compare and contrast techniques currently in use.

METHODS AND MATERIALS

A MEDLINE search was conducted to obtain all articles in the English language on prostate cancer brachytherapy from 1985 through 1998. Articles were reviewed and grouped to determine the primary technique of implantation, the method or philosophy of source placement and/or dose specification, the technique to evaluate implant quality, overall treatment results (based upon pretreatment prostate specific antigen, (PSA), and biochemical control) and clinical, pathological or biochemical outcome based upon implant quality.

RESULTS

A total of 178 articles were identified in the MEDLINE database. Of these, 53 studies discussed evaluable techniques of implantation and were used for this analysis. Of these studies, 52% used preoperative ultrasound to determine the target volume to be implanted, 16% used preoperative computerized tomography (CT) scans, and 18% placed seeds with an open surgical technique. An additional 11% of studies placed seeds or needles under ultrasound guidance using interactive real-time dosimetry. The number and distribution of radioactive sources to be implanted or the method used to prescribe dose was determined using nomograms in 27% of studies, a least squares optimization technique in 11%, or not stated in 35%. In the remaining 26%, sources were described as either uniformly, differentially, or peripherally placed in the gland. To evaluate implant quality, 28% of studies calculated some type of dose-volume histogram, 21% calculated the matched peripheral dose, 19% the minimum peripheral dose, 14% used some type of CT-based qualitative review and, in 18% of studies, no implant quality evaluation was mentioned. Six studies correlated outcome with implant dose. One study showed an association of implant dose with the achievement of a PSA nadir < or = 0.5. Two studies showed an improvement in biochemical control with a D90 (dose to 90% of the prostate volume) of 120 to 140 Gy or higher, and 2 additional studies found an association of clinical outcome with implant dose. One study correlated implant quality with biopsy results. Of the articles, 33 discussed evaluable treatment results, but only 16 reported findings based upon pretreatment PSA and biochemical control. Three- to 5-year biochemical control rates ranged from 48% to 100% for pretreatment PSAs < or = 4, 55% to 90% for PSAs between 4 and 10, 30% to 89% for PSAs > 10, < or = 20 and < 10% to 100% for PSAs > 20. Due to substantial differences in patient selection criteria (e.g., median Gleason score, clinical stage, pretreatment PSA), number of patients treated, median follow-up, definitions of biochemical control, and time points for analysis, no single technique consistently produced superior results.

CONCLUSIONS

Our comprehensive review of prostate cancer brachytherapy literature failed to identify an optimal treatment approach when studies were analyzed for treatment outcome based upon pretreatment PSA and biochemical control. Although several well-designed studies showed an improvement in outcome with total dose or implant quality, the numerous techniques for implantation and the varied and inconsistent methods to specify dose or evaluate implant quality suggest that standardized protocols should be developed to objectively evaluate this treatment approach. These protocols have recently been suggested and, when implemented, should significantly improve the reporting of treatment data and, ultimately, the efficacy of prostate brachytherapy.

The role of androgen deprivation in the definitive management of clinically localized prostate cancer treated with radiation therapy

PURPOSE

Multiple studies exploring the use of androgen deprivation given in combination with radiotherapy (RT) for localized prostate cancer have reported significant improvements in the rates of local, regional, and biochemical control (BC). The impact of this therapeutic strategy on overall and cancer specific survival (CSS) has not been established, however. We performed a MEDLINE search of all available studies on this topic to determine if any conclusions could be reached on the efficacy of this treatment approach and the patients most suitable for its application.

MATERIALS AND METHODS

A MEDLINE search was conducted to obtain all articles in the English language on the use of androgen deprivation in combination with RT for the treatment of localized prostate cancer. The medical subject headings (MeSH) used to search the MEDLINE database included: a) prostatic neoplasms; b) prostatic neoplasms/radiotherapy; c) prostatic neoplasms/androgen deprivation; d) hormone therapy; e) English; and f) 1980 to 1998.

RESULTS

A total of 14 retrospective studies were identified that compared some form of androgen deprivation given in combination with RT. Most studies showed significant improvements in various measures of local/regional control and disease-free survival (DFS). Three of four studies that analyzed BC rates showed significant improvements in this endpoint but conflicting results were obtained for overall survival (OS). No study showed an improvement in CSS. Six prospective randomized trials were identified that directly compared RT with or without androgen deprivation. Again, all six studies showed improvements in some measure of local/regional control or DFS but only two studies showed an improvement in OS. One study reported a statistically significant improvement in CSS and another study showed an improvement in the rate of negative biopsies with combined treatment.

CONCLUSIONS

When all available literature on androgen withdrawal given in combination with RT for the definitive treatment of localized prostate cancer was reviewed, no definite conclusions could be reached on the impact of this treatment approach on OS and CSS. However, local/regional control, DFS, and BC were almost uniformly improved with the use of androgen withdrawal suggesting that these impressive early results may translate into improved cure rates. Data from recently initiated and completed randomized trials will be needed, however, to define the impact of this approach on cancer specific mortality and the patients most suitable for it's use.

Update on the treatment of prostate cancer with external beam irradiation

BACKGROUND

We review the recent changes in the radiotherapeutic management of clinically localized prostate cancer, including the implementation of three-dimensional (3-D) conformal radiation therapy (3DCRT), biochemical disease-free survival (bNED control) using conventional and 3DCRT techniques, and the morbidity of these treatment strategies.

METHODS

The components of 3DCRT are discussed, including patient immobilization, 3-D treatment planning, multileaf collimation, and electronic portal imaging. bNED control rates from institutions using conventional and 3DCRT techniques are compared. The gastrointestinal (GI) and genitourinary (GU) morbidity from prospective trials using conventional doses of radiation are compared to data from 3DCRT series. bNED control rates stratified by pretreatment prostate-specific antigen (PSA) are compared between surgical and radiation series.

RESULTS

bNED control rates (3-5 years) for patients treated with conventional and 3DCRT techniques ranged from 44-70% and 30-72% with pretreatment PSA levels 4-10 and 10-20, respectively. Although direct comparisons are difficult between treatment modalities, no difference in bNED control stratified by pretreatment PSA was observed between surgical and radiation patients.

CONCLUSIONS

Patients with clinically localized prostate cancer treated with 3DCRT demonstrate durable bNED control at 5 years. Conformal radiation techniques, multileaf collimation, electronic portal imaging, and patient immobilization have reduced acute and chronic GI and GU morbidity while allowing safe dose escalation in an effort to further improve local control and overall survival.

Percent free prostate-specific antigen after radiotherapy for prostate cancer

OBJECTIVES

The range of "normal" prostate-specific antigen (PSA) values compatible with cure following radiotherapy (RT) for prostate cancer (PCa) has yet to be established. Various thresholds, ranging from 0.5 to 4.0 ng/mL are used to define biochemical disease-free status. Because the proportion of free PSA is lower in men with PCa, the ratio of free PSA to total PSA could theoretically be useful in determining cancer-free status after RT.

METHODS

One hundred two men treated with standard external beam RT from October 1988 to October 1994 (median dose, 66 Gy) were chosen for measurement of percent free PSA because they had a routine follow-up visit in November or December of 1996. All patients had undergone systematic transrectal ultrasound-guided biopsies after RT. Biopsies were negative in 66 patients, positive in 21, and indeterminate in 15 (rare, degenerated cancer cells with no evidence of proliferation by immunohistochemical stains). Stage distribution was T1b, 8; T1c, 9; T2a, 25; T2b/c, 40; and T3, 20. Median follow-up is 40 months.

RESULTS

Total serum PSA ranged from 0. 1 to 10.0 ng/mL. Because the mean (+/-SD) percent free PSA for patients with negative (n = 66) and indeterminate (n = 15) biopsies were 29% +/- 18% and 25% +/- 7%, respectively (P = 0.13), these were combined. The mean (+/-SD) percent free PSA for those with positive biopsies (n = 21) was 15% +/- 8% and was significantly different from those with negative or indeterminate biopsies (P < 0.001). Patients with negative or indeterminate biopsies were grouped according to their total PSA as 0.1 to 0.5 ng/mL (n = 33), 0.6 to 1.0 ng/mL (n = 23), 1.1 to 2.0 ng/mL (n = 17), and greater than 2.0 ng/mL (n = 7). The mean percent free PSAs were 34%, 28%, 21%, and 12%, respectively.

CONCLUSIONS

Percent free PSA may be a useful adjunct in diagnosing recurrent PCa after RT. The ratio is significantly different in patients of known biopsy status, distinguishing a group with positive biopsies from those with negative. However, there is overlap in individual values, and because patients with negative biopsies after RT may have subclinical distant disease, more follow-up is necessary before percent free PSA can be incorporated into a definition of biochemical disease-free status. Percent free PSA may be most useful for PSA from 0.6 to 2.0 ng/mL, where failure is common, but not universal.