Relationship of tumor DNA-ploidy to serum prostate-specific antigen doubling time after radiotherapy for prostate cancer

Tissue biomarkers for prostate cancer radiation therapy

Prostate cancer is the most common cancer and second leading cause of cancer deaths among men in the United States. Most men have localized disease diagnosed following an elevated serum prostate specific antigen test for cancer screening purposes. Standard treatment options consist of surgery or definitive radiation therapy directed by clinical factors that are organized into risk stratification groups. Current clinical risk stratification systems are still insufficient to differentiate lethal from indolent disease. Similarly, a subset of men in poor risk groups need to be identified for more aggressive treatment and enrollment into clinical trials. Furthermore, these clinical tools are very limited in revealing information about the biologic pathways driving these different disease phenotypes and do not offer insights for novel treatments which are needed in men with poor-risk disease. We believe molecular biomarkers may serve to bridge these inadequacies of traditional clinical factors opening the door for personalized treatment approaches that would allow tailoring of treatment options to maximize therapeutic outcome. We review the current state of prognostic and predictive tissue-based molecular biomarkers which can be used to direct localized prostate cancer treatment decisions, specifically those implicated with definitive and salvage radiation therapy.

[PSA and follow-up after treatment of prostate cancer]

A first serum total PSA assay is recommended during the first three months after treatment. When PSA is detectable, PSA assay should be repeated three months later to confirm this elevation and to estimate the PSA doubling time (PSADT). In the absence of residual cancer, PSA becomes undetectable by the first month after total prostatectomy: less than 0.1 ng/ml (or less than 0.07 ng/ml) for the ultrasensitive assay method and less than 0.2 ng/ml for the other methods. In the presence of residual cancer, PSA either does not become undetectable or increases after an initial undetectable period. A consensus has been reached to define recurrence as PSA greater than 0.2 ng/ml confirmed on two successive assays. After external beam radiotherapy, PSA can decrease after a mean interval of one to two years to a value less than 1 ng/ml (predictive of recurrence-free survival). Biochemical recurrence after radiotherapy is defined by an increase of PSA by 2 ng or more above the PSA nadir, whether or not it is associated with endocrine therapy. After endocrine therapy, the PSA nadir is correlated with recurrence-free survival. PSA is decreased for a mean of 18 to 24 months followed by a rise in PSA, corresponding to hormone-independence. The time to recurrence or the time to reach the nadir and the PSA doubling time after local therapy with surgery or radiotherapy have a diagnostic value in terms of the site of recurrence, local or metastatic and a prognostic value for survival and response to complementary radiotherapy or endocrine therapy. A PSADT less than eight to 12 months is correlated with a high risk of metastatic recurrence and 10-year mortality. The histological and biochemical characteristics in favour of local recurrence are Gleason score less or equal to seven (3+4), elevation of PSA after a period greater than 12 months and PSADT greater than 10 months. In other cases, recurrence is predominantly metastatic. The risk of demonstrating metastasis in the case of biochemical recurrence after total prostatectomy and before endocrine therapy depends on the PSA level and the PSADT. No consensus has been reached concerning the indication for complementary investigations by bone scan and abdominopelvic CT in patients with biochemical recurrence after treatment of localized cancer without endocrine therapy. However, when PSADT greater than six months, the risk of metastasis is less than 3% even for PSA greater than 30 ng/ml. When PSADT less than six months and PSA greater than 10 ng/ml, the risk of metastasis is close to 50%.

[Cell ploidy: predictive factor of locally advanced prostate cancer]

OBJECTIVE

This study was designed to demonstrate that the study of cell ploidy on biopsies of clinically localized prostate cancers can contribute to the diagnosis of a tumour extending beyond the prostatic capsule and can complete imaging for local staging.

METHODS

Analysis of the histological results of 140 patients operated for clinically localized prostate cancer distinguished two groups of patients in whom the initial tumour was Gleason score 6 or 7. The first group was composed of 33 patients whose tumour was classified as pT3 and the second group was composed of 24 patients whose tumour was classified as pT2. The cell ploidy study was performed on biopsies and operative specimens in the two groups.

RESULTS

In the pT3N0M0 group, 72% of tumours presented an aneuploid contingent versus 16% of tumours of the pT2N0M0 group. A strong correlation was demonstrated between cell ploidy and tumour stage (p = 0.0002) and a highly significant correlation was observed between tumour stage and the presence of a tumour contingent with ploidy greater than 5C (p = 0.0009).

CONCLUSION

The presence of an aneuploid contingent on biopsies of clinically localized prostate cancer significantly increases the risk of a more advanced tumour. This technique could therefore constitute a simple complementary tool in the staging of prostate cancer in combination with transrectal MRI, but this needs to be confirmed by other studies.

The cancer recognition (CARE) antibody test

The cancer recognition (CARE) antibody (Ab) test is a serologic assay for a specific IgM that is elevated in cancer patients. All tests are measured using an indirect enzyme-linked immunosorbent assay (ELISA) of human serum. The target polypeptide in the CARE Ab test is the IgM binding epitope (LT-11) of the CARE antigen (Ag) consisting of a 16 mer structure that has been produced synthetically. The mean relative concentration (MRC) is determined relative to standard, normalized human plasma. Non-parametric analysis showed median MRC values of healthy volunteers (HVs) with no history of cancer (n =47), family history of cancer (n = 126) and a previous cancer history (n = 24) to be 26, 34 and 46, respectively. It was determined that there was no significance found among the medians of the three HV groups (P = 0.53). The specificity of the HV types was between 87 and 98%. Benign/non-cancer surgical patients (n = 27) had a median value of 20 with a specificity of 96%. The cancer patients (n = 61) had a median value of 246 with a sensitivity of 89%. There was a significant difference between the HV and cancer patients (P < 0.0001) as well as between the benign/surgical non-cancerous group and cancer patients (P < 0.0001). The IgM antibody is heat stable at room temperature for two days versus being frozen at -80 degrees C (r2 = 0.97). Either serum or plasma samples may be used in the CARE Ab test (r2 = 0.92). The CARE Ab was almost exclusively IgM with no serum conversion to IgG in sequential measurements of patients with cancer over a six-month period. Preliminary data from patients undergoing post-operative cancer treatment showed that decreasing Ab levels revealed patients negative for residual cancer or undergoing remission, while relapsing patients show an increase in Ab levels. A return to a positive Ab level shortly after treatment is a poor prognostic sign while in advanced cancers the Ab levels may be depressed significantly.

Salvage radiotherapy in the treatment of prostate cancer

For patients undergoing radical prostatectomy for prostate adenocarcinoma, the most common cause of failure is an asymptomatic increase in levels of prostate-specific antigen (PSA). Salvage radiotherapy (RT) to the prostate bed has been used when there is no clinical evidence of metastatic disease. However, this is still not widely accepted because there is currently no consensus on the optimal management of an isolated PSA failure. Salvage RT given in a select group of patients is effective, with a 70% to 80% biochemical response rate and a long-term biochemical control rate as high as 35% to 40%. These data indicate that RT offers a substantial risk of curative salvage of patients who fail radical prostatectomy. Although there is interest in studying investigational modalities (eg, vaccine therapy) among patients with asymptomatic, PSA-detected recurrences after surgery, caution must be applied, and treatment modalities with known curative potential (ie, RT) should be used before noncurative techniques are attempted. This article outlines the rationale, results, and toxicity of salvage RT for an asymptomatic increase in PSA levels, with emphasis on identifying patients with favorable prognostic factors with higher rates of long-term biochemical control with local treatment.

Value of prostate specific antigen in predicting the existence of bone metastasis in scintigraphy

OBJECTIVE

Evaluate the ability of serum concentration of prostate specific antigen (PSA) between 2 cutting points to predict the existence of bone metastasis confirmed by bone scintigraphy in man with prostate cancer.

MATERIALS AND METHODS

Two hundred and fourteen consecutive patients with prostate cancer were evaluated during the present study in the period from 1998 to 2001. From all patients, PSA serum concentrations and bone scintigraphy were obtained. For the study, 2 cutting points of PSA (10 and 20 ng/mL) were adopted to predict the existence of bone metastasis.

RESULTS

From the 214 patients, 35 (16.3 x 0025;) presented positive scintigraphic examinations for the presence of bone metastasis. No patient presented bone metastasis in scintigraphy if having PSA < 10 ng/mL, and in only 1 patient (0.46 x 0025;) with bone metastasis PSA concentration was < 20 ng/mL. Therefore, when the cutting point adopted for PSA serum concentration was 10 ng/mL, a negative predictive value for bone metastasis was 100 x 0025; with sensitivity rates of 100%. Nevertheless, the positive predictive value and the specificity of the method were, respectively, 24.5 x 0025; and 39.7 x 0025;. When the cutting point of PSA serum concentration was 20 ng/mL, an increment was observed in rates of positive predictive value and specificity (41.5 x 0025; and 73.2 x 0025;), respectively, without substantial changes in negative predictive value (99.2 x 0025;) and sensitivity (97.1 x 0025;) of the method.

CONCLUSIONS

Data of present study allow for the conclusion that PSA serum concentration over 20 ng/mL was a more accurate cutting point than PSA serum concentration over 10 ng/mL to predict the presence of bone metastasis in scintigraphy.

Prostate cancer DNA ploidy and response to salvage hormone therapy after radiotherapy with or without short-term total androgen blockade: an analysis of RTOG 8610

PURPOSE

DNA ploidy has consistently been found to be a correlate of prostate cancer patient outcome. However, a minority of studies have used pretreatment diagnostic material and have involved radiotherapy (RT)-treated patients. In this retrospective study, the predictive value of DNA ploidy was evaluated in patients entered into Radiation Therapy Oncology Group protocol 8610. The protocol treatment randomization was RT alone versus RT plus short-course (approximately 4 months) neoadjuvant and concurrent total androgen blockade (RT+TAB).

PATIENTS AND METHODS

The study population consisted of 149 patients, of whom 74 received RT alone and 75 received RT+TAB. DNA content was determined by image analysis of Feulgen stained tissue sections; 94 patients were diploid and 55 patients were nondiploid. Kaplan-Meier univariate survival, the cumulative incidence method, and Cox proportional hazards multivariate analyses were used to evaluate the relationship of DNA ploidy to distant metastasis and overall survival.

RESULTS

DNA nondiploidy was not associated with any of the other prognostic factors in univariate analyses. In Kaplan-Meier analyses, 5-year overall survival was 70% for those with diploid tumors and 42% for nondiploid tumors. Cox proportional hazards regression revealed that nondiploidy was independently associated with reduced overall survival. No correlation was observed between DNA ploidy and distant metastasis. The diminished survival in the absence of an increase in distant metastasis was related to a reduction in the effect of salvage androgen ablation; patients treated initially with RT+TAB and who had nondiploid tumors had reduced survival after salvage androgen ablation.

CONCLUSIONS

Nondiploidy was associated with shorter survival, which seemed to be related to reduced response to salvage hormone therapy for those previously exposed to short-term TAB.

[Prognostic value of DNA ploidy in prostatic cancer]

OBJECTIVE

To asses the prognostic value of deoxyribonucleic acid (DNA) ploidy in a group of patients with prostate cancer treated with adrogenic blockade.

MATERIALS AND METHODS

A retrospective study on 136 patients with prostatic cancer having undergone androgenic blockade was carried out. The prognostic influence of age, T and M categories, Gleason score and flow cytometry-determined DNA ploidy from survival analyses. Univariate survival analysis was carried out following Kaplan-Meier's method, while for multivariate survival analysis Cox's proportional hazard model was used.

RESULTS

The univariante analysis showed that T and M categories, Gleason score and DNA ploidy have prognostic value. The Cox's regression analysis identified DNA ploidy, metastasis and Gleason score as independent variables having prognostic potential.

CONCLUSIONS

DNA ploidy has independent prognostic value in prostate cancer treated with androgenic blockade and improves the predictive potential of classical prognostic factors.

Fluorescence in situ hybridization aneuploidy as a predictor of clinical disease recurrence and prostate-specific antigen level 3 years after radical prostatectomy

OBJECTIVE

To determine if fluorescence in situ hybridization (FISH) analysis of fresh-tissue biopsy specimens obtained at the time of radical prostatectomy is able to predict prospectively clinical disease progression or prostate-specific antigen (PSA) level in patients 3 to 4 years after surgery.

MATERIALS AND METHODS

FISH analysis was performed on fresh-tissue touch preparations obtained from 90 randomly selected radical prostatectomy specimens. Cut surface touch preparations from 40 specimens resected in 1992 were analyzed with DNA probes for chromosomes 4, 6-12, 17, 18, X, and Y. Needle-biopsy specimens were obtained from 50 tumors resected in 1993, and touch preparations from these specimens were studied with DNA probes for chromosomes 7, 8, 11, and 12. Serum PSA levels and clinicopathologic data were recorded, and each patient was followed up from the time of surgery to determine cancer progression.

RESULTS

Of 90 patients undergoing radical prostatectomy in 1992 and 1993, 89 returned for follow-up. Three patients received preoperative hormonal therapy, and in 2 patients, antiandrogen therapy was continued postoperatively. Fifteen patients underwent intraoperative orchiectomy immediately after radical prostatectomy, while 9 patients had postoperative adjuvant hormonal therapy. Six patients underwent postoperative radiation therapy. Fourteen patients (15.7%) demonstrated systemic, local, or PSA progression. Only 2 (4.7%) of 43 patients with FISH diploid tumors demonstrated cancer progression. Conversely, 10 (30.3%) of 33 FISH aneuploid and 12 (26.1%) of 46 FISH nondiploid tumors demonstrated cancer progression (P=.004 and P=.006, respectively). Unlike FISH, flow cytometric aneuploidy was not associated with early cancer progression. Elevated preoperative PSA concentration, increased preoperative and postoperative Gleason score, and increased preoperative and postoperative T or N stage were not statistically significantly associated with cancer progression. While chromosome 7 and 8 aneusomies were not statistically associated with cancer progression, 2 of 5 (P=.04) chromosome 12 aneusomic tumors demonstrated cancer progression.

CONCLUSION

Early (within 4 years) local, systemic, or PSA progression occurred more frequently (P<.05) in radical prostatectomy patients with FISH aneuploid, nondiploid, and chromosome 12 aneusomic tumors. Flow cytometric ploidy status, preoperative serum PSA concentration, and clinical or pathologic grade or stage, including seminal vesicle involvement, margin status, and capsular perforation status, were not associated with early prostate cancer progression in this group of 89 patients. FISH analysis appears to be a useful preoperative tool for predicting aggressive vs indolent prostate cancer.

Radiotherapy options for localized prostate cancer based upon pretreatment serum prostate-specific antigen levels and biochemical control: a comprehensive review of the literature

PURPOSE

To review all the available radiotherapy (RT) literature on localized prostate cancer treatment where serum prostate-specific antigen (PSA) levels were used to both stratify patients and evaluate outcome and determine if any conclusions can be reached regarding an optimal radiotherapeutic management for this disease.

METHODS AND MATERIALS

A MEDLINE search was conducted to obtain all articles in English on prostate cancer treatment employing RT from 1986-1997. Studies were considered eligible for review only if they met all the following criteria: 1) pretreatment PSA values were recorded and grouped for subsequent evaluation, 2) posttreatment PSA values were continuously monitored, 3) definitions of biochemical control were stated, and 4) the median follow-up was given.

RESULTS

Of the 246 articles identified, only 20 met the inclusion criteria; 4 using conformal external beam RT, 8 using conventional external beam RT, and 8 using interstitial brachytherapy (4 using a permanent implant alone, 3 combining external beam RT with a permanent implant, and 1 combining a conformal temporary interstitial implant boost with external beam RT). No studies using neutrons (with or without external beam RT) or androgen deprivation (combined with external beam RT) were identified where patients were stratified by pretreatment PSA levels. Results for all therapies were extremely variable with the 3-5-year rates of biochemical control for patients with pretreatment PSA levels < or = 4 ng/ml ranging from 48 to 100%, for PSA levels >4 and < or = 10 ng/ml ranging from 44 to 90%, for PSA levels >10 and < or = 20 ng/ml ranging from 27 to 89%, and for PSA levels >20 ranging from 14 to 89%. The median Gleason score, T-stage, definition of biochemical control, and follow-up were substantially different from series to series. No RT option consistently produced superior results.

CONCLUSIONS

When data are reviewed from studies using serum PSA levels to stratify patients and to evaluate treatment outcome, no consistently superior RT technique was identified. These data suggest that standard definitions of disease stage (combining clinical, pathologic, and biochemical criteria) and a common definition of biochemical cure (as developed by the American Society for Therapeutic Radiology and Oncology Consensus Panel) need to be adopted to evaluate treatment efficacy and advise patients on the most appropriate radiotherapeutic option for their disease.

Watchful waiting or watchful progression?: Prostate specific antigen doubling times and clinical behavior in patients with early untreated prostate carcinoma

BACKGROUND

Prostate specific antigen doubling time (PSAdt) is a dynamic model of prostate tumor biology. It predicts aggressive disease and subsequent clinical recurrence after radical treatment. However, as yet there is only limited evidence for its validity in the watchful waiting population.

METHODS

One hundred and thirteen previously untreated patients with adenocarcinoma of the prostate who were referred to the British Columbia Cancer Agency for a management opinion subsequently were placed into a prospective watchful waiting program. The reasons for watchful waiting, previous medical history, serial PSA, and histopathologic data were recorded.

RESULTS

The median age of patients was 75 years (range, 49-85 years). The median follow-up from the time of the first appointment was 14 months (range, 0-58 months). The reasons for watchful waiting were correlated highly with T classification (P = 0.003) and past medical history (P = 0.002). Approximately 40% of T1 patients and 51% of T2 patients had clinical progression by 2 years, increasing to 60% at 3 years. On multivariate analysis PSAdt strongly correlated with clinical progression (P < 0.0001), stage progression (P = 0.01), and time to treatment (P = 0.0001); tumor grade and initial stage were not found to be predictive for any of the endpoints studied. Initial PSA only was significant in predicting for time to treatment (P = 0.03). Approximately 50% of patients with a PSAdt of <18 months progressed within 6 months. At last follow-up, no deaths from prostate carcinoma had been recorded. Overall survival at 2 and 5 years was 92% and 68%, respectively.

CONCLUSIONS

Using digital rectal examination, the findings of this study demonstrated high rates of clinical tumor progression within the watchful waiting population. PSAdt rather than standard histopathologic criteria was found to be the most powerful indicator of disease activity.

Kinetics of serum prostate-specific antigen after external beam radiation for clinically localized prostate cancer

BACKGROUND AND PURPOSE

To determine the kinetics of serum prostate-specific antigen (PSA) after radiation therapy of localized prostate cancer and to evaluate whether such kinetics provide prognostic information.

MATERIALS AND METHODS

Eight hundred forty-one men with serial PSA determinations who underwent external beam radiation without androgen ablation were analyzed to determine postradiation PSA kinetic parameters (half-life and doubling time) and to correlate these parameters with disease outcome. Non-linear regression techniques were used to determine half-lives and doubling times.

RESULTS

The postradiation serum PSA data fitted well to first order kinetic models. The median PSA half-life was 1.6 months (range 0.5-9.2 months). There was no correlation between half-life and T-stage or Gleason grade. A significant but quantitatively weak correlation was present between the pretreatment PSA level and half-life; lower pretreatment levels were associated with longer half-lives. Half-life did not correlate with disease outcome whether the endpoint was local recurrence, distant metastasis or rising PSA. In 263 men with a rising postradiation PSA profile the median PSA doubling time was 12.2 months (range 0.8-80.2 months). Faster doubling times were significantly associated with higher T-stage, higher Gleason grade and higher pretreatment PSA levels. Thus, patients with initially adverse disease developed faster rising PSA values after treatment than patients with less adverse disease. The most striking correlation was between rapid doubling time and the likelihood of metastatic relapse. Patients who developed metastases had a median PSA doubling time of 4.2 months compared to a median doubling time of 11.7 months in patients who developed local recurrence. Overall, patients with a PSA doubling time of less than 8 months had a 7-year actuarial metastatic rate of 54%, while patients with a PSA doubling time exceeding 8 months had only a 7% metastatic rate. Particularly ominous was the combination of a doubling time shorter than 8 months which began to rise within the first year; by 3 years 50% of these men had metastases and all were actuarially projected to develop such relapse by 6.5 years.

CONCLUSIONS

Overall, the clinical utility of postradiation serum PSA kinetics was small. There were no discernible uses for PSA half-life. In patients with a rising PSA profile the faster the kinetics the more adverse the disease. Doubling times shorter than 8 months, especially if the rise begins in the first year, predict for metastatic relapse. However, in the absence of decisively useful treatment for metastatic prostate cancer the virtues of the early detection of metastases remain unclear.

The significance of DNA-ploidy and S-phase fraction in node-positive (stage D1) prostate cancer treated with androgen ablation

BACKGROUND

The prognostic significance of primary tumor DNA-ploidy and S-phase fraction (SPF) was evaluated in patients treated with androgen ablation for regionally localized node-positive prostate cancer.

METHODS

All patients were diagnosed with lymph node involvement by pelvic lymphadenectomy between 1984 and 1992 and were treated only with androgen ablation. Median follow-up was 45 months. Adequate material for DNA/nuclear protein flow cytometric analysis was available in 33 patients.

RESULTS

The tumors were classified as diploid in 11, near-diploid in 4, tetraploid in 10, and aneuploid in 8 cases. Grouping the patients by nonaneuploidy (diploid and near-diploid and tetraploid) and aneuploidy revealed actuarial 4-year disease progression rates of 14 and 48% (log-rank, P = 0.04), and overall survival rates of 100 and 61% (P = 0.008); however, biochemical progression (rising prostate-specific antigen profile) rates were similar at around 70%. In contrast, SPF was not significantly related to any of the endpoints tested. Several other potential prognostic factors were examined and none correlated significantly with disease progression or survival.

CONCLUSIONS

The biochemical progression rates for patients with nonaneuploid and aneuploid tumors were comparable and high, while the disease progression rates were higher and survival rates lower for those with aneuploid tumors. These data indicate that the lead time from biochemical to disease progression and death was shorter with aneuploidy. That these relationships were observed in such a small patient population attest to the strength of DNA-ploidy as a prognostic factor in this cohort.

The prostate: decreasing cost-effectiveness of biopsy with advancing age

RATIONALE AND OBJECTIVES

The purpose of this study was to determine the cost-effectiveness of prostate biopsy at different excess prostate-specific antigen (PSA) levels as a function of age.

METHODS

Medical decision analysis was performed with standard software (SMLTREE) to determine marginal effectiveness in quality adjusted life years (QALYs) and marginal cost-effectiveness in dollars per QALY of immediate prostate biopsy at different excess PSA levels between 0 ng/mL and 20 ng/mL. The probability of clinically significant cancer with a positive biopsy (pD+Bx+) was assumed to decrease with age from 1.0 at age 50 to 0.2 at age 70. Costs were based on charges at our hospital and were considered over a 2-year time frame.

RESULTS

With our base case assumptions there was a decrease in QALYs and an increase in costs doing an immediate prostate biopsy at all excess PSA levels between 0 ng/mL and 20 ng/mL, compared with not biopsying the prostate at > or = 70 years. Doubling pD+Bx+ from 0.2 to 0.4 in the 70-and-older age group resulted in a small increase in QALYs in biopsying the prostate at excess PSA levels between 0 ng/mL and 20 ng/mL. However, the marginal cost-effectiveness of prostate biopsy was very high, ranging from $275,000/QALY biopsying at an excess PSA level of 0 ng/mL to $68,000/QALY biopsying at an excess PSA level of 20 ng/mL. This compared with it being more effective and less costly to biopsy at all excess PSA levels > or = 0 ng/mL in 50-year old patients.

CONCLUSION

Immediate prostate biopsy is not cost-effective and can be detrimental in patients > or = 70 years of age at all excess PSA levels between 0 ng/mL and 20 ng/mL.

Pretreatment prostate-specific antigen doubling times: clinical utility of this predictor of prostate cancer behavior

PURPOSE

The distribution of pretreatment and posttreatment prostate specific antigen (PSA) doubling times (PSADT) varies widely. This report examines the pretreatment PSADT as an independent predictor of biochemical freedom from disease (bNED) and describes the clinical utility of PSADT.

METHODS AND MATERIALS

Ninety-nine patients with T1-3 NX, M-0 prostate cancer treated between February 1989 and November 1993 have pretreatment PSADTs calculated from three or more PSA levels. Biochemical disease-free (bNED) survival (failure is PSA > or = 1.5 ngm/ml and rising) is evaluated by multivariate analysis of common prognostic indicators and PSADT.

RESULTS

Prostate-specific antigen doubling time (PSADT) is a significant predictor of survival along with radiation dose. Patients with a pretreatment PSADT of < 12 months show 50% failure by 18 months, while those with a PSADT that is not increasing show only 3% failure at 3 years.

CONCLUSIONS

Prostate-specific antigen doubling time (PSADT) is a predictor of bNED outcome in prostate cancer. Patients with PSADT < 12 months have aggressive disease, and should be considered for multimodal therapy. Slow PSADT (> or = 5 years) is observed in 57% of patients, and this end point may be considered in the decision to observe rather than to treat. After treatment failure, the PSADT may be used to determine which patients do not need immediate androgen deprivation.

Prostate-specific antigen and radiation therapy for clinically localized prostate cancer

PURPOSE

This study was undertaken to: (a) define the prognostic significance of pretreatment serum prostate-specific antigen (PSA) levels in localized prostate cancer treated with radiation; (b) define the prognostic usefulness of postradiation PSA levels; (c) evaluate the outcome of radiation using PSA as an endpoint.

METHODS AND MATERIALS

Disease outcome in 707 patients with Stages T1 (205 men), T2 (256 men), T3 (239 men), and T4 (7 men), receiving definitive external radiation as sole therapy, was evaluated using univariate and multivariate techniques.

RESULTS

At a mean follow-up of 31 months, 157 patients (22%) developed relapse or a rising PSA. Multivariate analysis revealed pretreatment PSA level to be the most significant prognostic factor, with lesser though significant contributions due to Gleason grade (2-6 vs. 7-10) and transurethral resection in T3/T4 disease. The following four prognostic groupings were defined: group I, PSA < or = 4 ng/ml, any grade; group II, 4 < PSA < or = 20, grades 2-6; group III, 4 < PSA < or = 20, grades 7-10; group IV, PSA > 20, any grade. Five-year actuarial relapse rates in these groups were: I, 12%; II, 34%; III, 40%; and IV, 81%. Posttreatment nadir PSA was an independent determinant of outcome and only patients with nadir values < 1 ng/ml fared well (5-year relapse rate 20%). Using rising PSA as an endpoint the 461 patients with T1/T2 disease had an actuarial freedom from disease rate of 70% at 5 years, which appeared to plateau, suggesting that many were cured. No plateau was evident for T3/T4 disease.

CONCLUSION

Pretreatment serum PSA is the single most important predictor of disease outcome after radiation for local prostate cancer. Tumor grade has a lesser though significant prognostic role. Postirradiation nadir PSA value during the first year is a sensitive indicator of response to treatment. Only nadir values < 1 ng/ml are associated with a favorable outlook. A significant fraction of men with T1/T2 disease may be cured with radiation. There was no evidence for a cured fraction among patients with T3/T4 disease.

Radiation therapy for T1 and T2 prostate cancer: prostate-specific antigen and disease outcome

OBJECTIVES

To evaluate disease outcome using serum prostate-specific antigen (PSA) as an outcome measure in patients with T1 or T2 prostate cancer treated with radiation therapy in the PSA era.

METHODS

We reviewed the outcome for 461 patients with T1 (n = 205) or T2 (n = 256) prostate cancer followed for a median of 31 months after radiation therapy as the sole initial treatment. Univariate and multivariate analyses were used to delineate significant prognostic factors.

RESULTS

The freedom from relapse or rising PSA rate was 70% at 6 years and the survival rate was 83%. Although T stage, Gleason grade, serum prostatic acid phosphatase level, and serum PSA level were each significant determinants of outcome in univariate analysis, pretreatment PSA level was the only clearly independent covariate (P < 0.0001) in multivariate analysis. The 5-year actuarial freedom from relapse or from rising PSA levels is shown according to the pretreatment PSA level: 4 ng/mL or less (117 patients), 91%; more than 4 but 10 ng/mL or less (169 patients), 69%; more than 10 but 20 ng/mL or less (118 patients), 62%; and more than 20 ng/mL (57 patients), 38%. PSA doubling times in 75 patients with rising post-treatment profiles ranged from 1.3 to 78.2 months (mean, 14.4; median 11.3). Faster doubling times correlated significantly with adverse pretreatment prognostic factors (high-grade, high pretreatment PSA, and aneuploidy). To date, the survival rate of patients with rising PSA profiles was not depressed below the expected.

CONCLUSIONS

Radiation therapy is an acceptable modality for treating T1 or T2 disease and produces results comparable to those following radical prostatectomy when patients are stratified according to their pretreatment PSA value. The rapid PSA doubling times observed in patients with relapsing disease are more consistent with a "selective" rather than an "aggravation" mechanism.