The prognostic significance of post-irradiation biopsy results in patients with prostatic cancer

Longitudinal Changes and Predictive Value of Multiparametric MRI Features for Prostate Cancer Patients Treated with MRI-Guided Lattice Extreme Ablative Dose (LEAD) Boost Radiotherapy

We investigated the longitudinal changes in multiparametric MRI (mpMRI) (T2-weighted, Apparent Diffusion Coefficient (ADC), and Dynamic Contrast Enhanced (DCE-)MRI) of prostate cancer patients receiving Lattice Extreme Ablative Dose (LEAD) radiotherapy (RT) and the capability of their imaging features to predict RT outcome based on endpoint biopsies. Ninety-five mpMRI exams from 25 patients, acquired pre-RT and at 3-, 9-, and 24-months post-RT were analyzed. MRI/Ultrasound-fused biopsies were acquired pre- and at two-years post-RT (endpoint). Five regions of interest (ROIs) were analyzed: Gross tumor volume (GTV), normally-appearing tissue (NAT) and peritumoral volume in both peripheral (PZ) and transition (TZ) zones. Diffusion and perfusion radiomics features were extracted from mpMRI and compared before and after RT using two-tailed Student t-tests. Selected features at the four scan points and their differences (Δ radiomics) were used in multivariate logistic regression models to predict the endpoint biopsy positivity. Baseline ADC values were significantly different between GTV, NAT-PZ, and NAT-TZ (p-values < 0.005). Pharmaco-kinetic features changed significantly in the GTV at 3-month post-RT compared to baseline. Several radiomics features at baseline and three-months post-RT were significantly associated with endpoint biopsy positivity and were used to build models with high predictive power of this endpoint (AUC = 0.98 and 0.89, respectively). Our study characterized the RT-induced changes in perfusion and diffusion. Quantitative imaging features from mpMRI show promise as being predictive of endpoint biopsy positivity.

Two-years Postradiotherapy Biopsies: Lessons from MRC RT01 Trial

BACKGROUND

The importance of 2-yr postradiotherapy prostate biopsy status remains uncertain.

OBJECTIVE

To assess the value of 2 year post treatment biopsies in a randomised trial of radiotherapy dose escalation.

DESIGN, SETTING, AND PARTICIPANTS

Between 1998 and 2001, 843 men with localised prostate cancer were randomised to receive either control-64Gy or escalated-74Gy conformal radiotherapy (CFRT) in the MRC RT01 trial in combination with 3-6-mo neoadjuvant androgen deprivation therapy. Prostate biopsies were planned at 2 yr from start of CFRT in suitable men.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Prostate biopsy results and prostate-specific antigen (PSA) levels performed at 2 yr post-CFRT were evaluated with long-term biochemical progression free survival (bPFS) and overall survival. Outcome measures were timed from the 2-yr biopsy using a landmark approach.

RESULTS AND LIMITATIONS

A 2-yr biopsy was performed in 312/843 patients. One hundred and seventy-seven patients were included in the per-protocol group with median follow-up of 7.8 yr from biopsy. Median PSA at biopsy was 0.5ng/ml. Sixty-four bPFS events were reported: 46/145 (32%) in patients with negative, 6/18 (33%) suspicious, and 12/14 (86%) positive biopsies. A positive biopsy was prognostic of worse bPFS, going forward, compared with negative and suspicious biopsies, hazard ratio (HR)=4.81 (95% confidence interval [CI]: 2.50-9.26, p<0.001). The estimate for survival was HR=1.58 (95% CI: 0.52-4.78, p=0.42). PSA values at 2 yr between 1.01ng/ml and 2.09ng/ml were also associated with subsequent PSA failures (HR=2.71, 95% CI: 1.98-3.71), bPFS events (HR=2.45, 95% CI: 1.81-3.32), and prostate cancer-specific survival (HR=2.87, 95% CI: 1.08-7.64) compared with PSA ≤1.0ng/ml.

CONCLUSIONS

Two-year postradiotherapy prostate biopsies have limited value in patients with PSA control but both positive biopsy and higher PSA status are strongly associated with future bPFS events. A policy of selected biopsy may provide an opportunity for early salvage interventions.

PATIENT SUMMARY

Routine 2-yr postradiotherapy biopsy is not recommended but can be considered in selected patients with unfavourable post-treatment prostate-specific antigen levels who are suitable for early salvage treatments.

Canine prostate: contrast-enhanced US-guided radiofrequency ablation with urethral and neurovascular cooling--initial experience

PURPOSE

To prospectively evaluate in a canine model contrast material-enhanced ultrasonography (US) for guiding and monitoring radiofrequency (RF) ablation of the entire prostate, with urethral and vascular cooling to protect the surrounding structures.

MATERIALS AND METHODS

After approval by the institutional animal use and care committee, an RF electrode was used to ablate the entire prostate in 15 dogs. During ablation, pulse-inversion harmonic US was performed by using an endocavitary probe after an intravenous bolus injection (0.04 mL/kg) and infusion (0.015 muL/kg/min) of a US contrast agent. In group 1 (n = 4), no cooling protection was used during ablation. In group 2 (n = 5), urethral and bladder protection was provided by inserting a 12-F catheter infused with cold saline (8 degrees C +/- 4 [standard deviation]) at a rate of 100 mL/min. In group 3 (n = 6), further protection of the neurovascular bundles (NVBs) was provided by infusing cold saline (8 degrees C +/- 4) into the iliac arteries at a rate of 50 mL/min by means of catheterization of the femoral artery. Pathologic findings among the three groups were compared by using the Wilcoxon rank sum test.

RESULTS

The average volumes of prostate ablation achieved in the three groups were 96.6%, 91.9%, and 92%. Contrast-enhanced pulse-inversion harmonic US allowed visualization and monitoring of urethral and NVB blood flow during the ablation. Without protection, damage to the urethra and the NVB was demonstrated at both US and pathologic examination. There was highly significant difference in urethral damage between groups with and the group without urethral cooling (P = .002), while intraarterial cooling demonstrated a nonsignificant trend toward a decreased NVB damage (P = .069).

CONCLUSION

Contrast-enhanced US can guide RF ablation of the entire prostate. Infusion of cold saline provides effective protection for the urethra during such procedures. The application of intraarterial cooling did not provide a significant improvement in the protection of the NVB in this small study.

Lack of prognostic significance of prostate biopsies in metastatic androgen independent prostate cancer

OBJECTIVE

To assess the significance of viable tumour in the prostate of patients with metastatic androgen-independent prostate cancer (AIPC).

PATIENTS AND METHODS

We evaluated the clinicopathological features, including follow-up, of 40 men with metastatic AIPC who had a transrectal biopsy of the prostate.

RESULTS

Prostate biopsies (median three cores per biopsy) showed viable tumour in 19 of 40 patients (48%). Of the 18 patients who had received radiotherapy (RT), nine had negative on-study biopsy results. A previous history of RT was not associated with overall survival in patients with biopsy-positive tumours (P = 0.84). Also, there was no statistically significant association between positive or negative biopsy status and overall survival (OS) in these 40 patients (P = 0.39), with a similar median OS of 19.6 months for biopsy-negative and 19.8 months for biopsy-positive patients, respectively.

CONCLUSIONS

Taking prostate biopsies at the time of documented metastatic AIPC yielded tumour in about half the patients. A previous history of RT was not associated with a negative prostate biopsy; the latter appears to have no influence on the prognosis.

The predictive value of 2-year posttreatment biopsy after prostate cancer radiotherapy for eventual biochemical outcome

PURPOSE

To determine the value of a 2-year post-radiotherapy (RT) prostate biopsy for predicting eventual biochemical failure in patients who were treated for localized prostate cancer.

METHODS AND MATERIALS

This study comprised 164 patients who underwent a planned 2-year post-RT prostate biopsy. The independent prognostic value of the biopsy results for forecasting eventual biochemical outcome and overall survival was tested with other factors (the Gleason score, 1992 American Joint Committee on Cancer tumor stage, pretreatment prostate-specific antigen level, risk group, and RT dose) in a multivariate analysis. The current nadir + 2 (CN + 2) definition of biochemical failure was used. Patients with rising prostate-specific antigen (PSA) or suspicious digital rectal examination before the biopsy were excluded.

RESULTS

The biopsy results were normal in 78 patients, scant atypical and malignant cells in 30, carcinoma with treatment effect in 43, and carcinoma without treatment effect in 13. Using the CN + 2 definition, we found a significant association between biopsy results and eventual biochemical failure. We also found that the biopsy status provides predictive information independent of the PSA status at the time of biopsy.

CONCLUSION

A 2-year post-RT prostate biopsy may be useful for forecasting CN + 2 biochemical failure. Posttreatment prostate biopsy may be useful for identifying patients for aggressive salvage therapy.

Histological changes in prostate biopsies after salvage cryotherapy: effect of chronology and the method of biopsy

OBJECTIVES

To examine changes in prostate biopsies at different intervals after salvage cryotherapy and the effect of biopsy type (transrectal ultrasonography-guided vs transurethral resection, TUR), as the sequence and extent of histological changes occurring in the prostate after salvage cryotherapy for local failure of prostate cancer treatment are unknown.

PATIENTS AND METHODS

In all, 158 prostate biopsies from 150 patients were examined histologically after salvage cryotherapy for prostate cancer after radiotherapy had failed. Specimens were grouped by time from cryotherapy and biopsy technique.

RESULTS

Biopsies showed hyalinization, necrosis, inflammation and residual cancer. Hyalinization became predominant over time, most notably in biopsies with no residual cancer. Core biopsies showed more hyalinization and regenerating glands, while TUR biopsies showed more necrosis and inflammation.

CONCLUSIONS

Tissue cryo-injury and reactive changes last for >1 year; more extensive cryo-injury suggests more effective cancer ablation. A long-term follow-up is necessary, as prostate cancer might remain indolent for >1 year.

Efficacy of High Dose Per Fraction Radiation for Implanted Human Prostate Cancer in a Nude Mouse Model

PURPOSE

SBRT is a new therapeutic paradigm using large dose per fraction treatments (aggressive hypofractionation). While SBRT has shown efficacy for treating patients with lung, liver and spine tumors, to our knowledge there have been no preclinical studies evaluating the efficacy of this treatment for prostate cancer. We investigated the dose-response characteristics of SBRT for treating human prostate cancer in a nude mouse model.

MATERIALS AND METHODS

Nude mice were injected subcutaneously into the right flank with C4-2 prostate cancer cells grown in culture. A dose escalation trial was performed to assess toxicity and response. Tumor bearing animals were radiated with 3 fractions (1 per week) for a total dose of 15 Gy in 11, 22.5 Gy in 9 and 45 Gy in 10, while 8 untreated animals served as controls. The mice were weighed, and tumor volume and PSA measurements were performed at baseline and weekly until 4 weeks after treatment.

RESULTS

There was no treatment related toxicity. There was a significant difference in the tumor response to higher radiation doses. In the 15 and 22.5 Gy groups mean tumor volume decreased to 58% and 90% of the original volume, respectively, but the rats experienced progressive tumor regrowth within 1 week after the completion of therapy. The 45 Gy group had a mean tumor volume and PSA decrease of greater than 90%, which was sustained 1 month after treatment in all except 2 mice.

CONCLUSIONS

SBRT dose level treatments were able to significantly decrease tumor volume and PSA. However, using 15 and 22.5 Gy durable responses were not achieved except in a few mice. The 45 Gy group demonstrated sustained PSA and tumor volume decreases in most mice. These results clearly show an increasing dose-response relationship for a range of hypofractionated dose levels, as used in SBRT.

Recurrent prostate cancer after external beam radiotherapy: value of contrast-enhanced dynamic MRI in localizing intraprostatic tumor--correlation with biopsy findings

OBJECTIVES

To assess the accuracy and interobserver variability of T2-weighted (T2W) and contrast-enhanced dynamic (CE-Dyn) magnetic resonance imaging (MRI) in predicting the results of transrectal biopsy in patients with suspected recurrent prostate cancer after external beam radiotherapy.

METHODS

A total of 22 patients with increasing prostate-specific antigen levels after external beam radiotherapy for prostate cancer underwent T2W and CE-Dyn MRI of the prostate. The CE-Dyn sequence (acquisition time 30 seconds) was repeated three times after the injection of gadolinium. All patients underwent subsequent transrectal biopsy. Three independent readers interpreted the MRI scans. The MRI and biopsy results were correlated in 10 prostate sectors (the sextants of the peripheral zone, the two transitional zones, and the two seminal vesicles).

RESULTS

Biopsy cores were obtained in 147 prostate sectors. Of these, 63 were positive for cancer in 19 patients. On the T2W images, the three readers interpreted as positive for cancer 15, 15, and 13 of the 19 patients showing cancer at biopsy. They interpreted as negative 3, 0, and 1 of the 3 patients showing no cancer at biopsy. On CE-Dyn images, the three readers correctly classified all the patients as positive or negative for cancer. The T2W and CE-Dyn MRI findings were concordant with biopsy results in, respectively, 81 to 95 and 107 to 117 prostate sectors (P <0.001 and P <0.01 for readers 1 and 2 and was nonsignificant for reader 3). The interobserver agreement was better for CE-Dyn images (kappa = 0.63 to 0.70) than for the T2W images (kappa = 0.18 to 0.39). The MRI-calculated tumor volumes and the mean biopsy core invasion rates were significantly correlated on the CE-Dyn images for all readers. They correlated significantly on T2W images only for one reader.

CONCLUSIONS

CE-Dyn MRI depicts the intraprostatic distribution of recurrent cancer after external beam radiotherapy more accurately and with less interobserver variability than T2W MRI.

Salvage therapy for locally recurrent prostate cancer after external beam radiotherapy

The greatest obstacle in the cure of patients with locally recurrent prostate cancer after radiation therapy is the lack of early detection markers. The majority of patients who are candidates for local salvage therapy have locally advanced disease, precluding successful salvage therapy. A low pretreatment prostate specific antigen (PSA) has shown to be a favorable prognostic variable for disease progression, regardless of the specific local salvage therapy used. Of all the local salvage treatment options for these patients, we believe that salvage radical prostatectomy (RP) offers patients the greatest likelihood of a cure. The salvage RP results approach those achieved with standard RP for patients of similar pathologic stage. When patients are treated early in the course of recurrent disease (preoperative PSA < 10 ng/mL), an estimated two-thirds of patients will be disease-free 5 years after salvage RP alone. With better patient selection and continued technical modifications, the morbidity associated with salvage RP has substantially improved. Perioperative complications approach those observed with standard RP and approximately two-thirds of patients will recover urinary continence. Select patients may also recover functional erections when nerve-sparing techniques are used. Salvage cryotherapy and brachytherapy are minimally invasive alternatives to salvage RP. The cancer control results of these procedures appear to be inferior to results achieved with salvage RP. Each of these procedures is associated with significant morbidity and do not appear to provide a clear advantage over salvage RP in terms of posttreatment complications, urinary continence, and erectile function. A long-term cure is possible for patients with locally recurrent prostate cancer after radiation therapy. Local salvage therapy must be instituted early to be successful in the course of progressive disease.

Incomplete glandular ablation after salvage cryotherapy for recurrent prostate cancer after radiotherapy

PURPOSE

To determine the clinical variables associated with inadequate salvage cryotherapy and to correlate the disease-free survival rates associated with biopsy results in prostate cancer (CaP).

METHODS AND MATERIALS

Between July 1992 and January 1995, 150 patients underwent salvage cryotherapy for locally recurrent CaP. Biopsy specimens were examined for the presence of cancer cells and normal or atypical glands, all of which were considered evidence of inadequate cryotherapy. Clinical variables, as predictors of biopsy results, were evaluated with univariate and multivariate analyses. The impact of the biopsy results on disease-free survival was also determined.

RESULTS

The number of cryoprobes and freeze-thaw cycles correlated with inadequate cryotherapy (p = 0.037 and p = 0.0022, respectively). The number of freeze-thaw cycles was an independent predictor of inadequate cryotherapy (p = 0.003). The finding of cancer cells in the biopsy specimens was the only histopathologic variable that affected disease-free survival (p = 0.016).

CONCLUSION

Complete ablation of the prostate gland and tumor is difficult to achieve with salvage cryotherapy. To optimize for complete ablation, salvage cryotherapy should include at least two freeze-thaw cycles and a minimum of five cryoprobes. The finding of atypical or normal epithelial tissue in biopsy specimens after salvage cryotherapy is not predictive of biochemical failure.

Contemporary pathology of prostate cancer

In less than 20 years since the introduction of serum PSA and the spring-loaded 18-gauge prostatic biopsy needle, pathologists have adjusted to the limited tissue requirements of narrow needle specimens to apply criteria for diagnosis and grading of prostate cancer, borrowing from lessons learned from radical prostatectomies. Substantial gains have been made during this period in the understanding of precancerous lesions, mimics of malignancy, the criteria for minimal cancer, variants of cancer, and treatment-induced changes. The light microscopic findings remain the criterion standard for diagnosis against which all new techniques should be measured. Numerous findings have proven to be of value, including simple quantitation of histopathologic features, cancer volume, perineural invasion, and others.

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

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

National Comprehensive Cancer Network guidelines for the management of prostate cancer

Guidelines for the management of prostate cancer issued by the National Comprehensive Cancer Network provide a basis for rational treatment decisions. These guidelines represent consensus recommendations by a panel of experts that are evidence based and are designated according to the degree of consensus within the expert panel. The initial stratification point is the patient's life expectancy (>5 or <5 years). If life expectancy is >5 years, the recommended intervention is based on clinical stage, prostate-specific antigen (PSA) level, and Gleason score, as well as the presence of symptoms. These assessments establish the patient's risk of recurrence after therapy. Specific initial therapies are then recommended according to whether the risk category is low, intermediate, high, or very high. The guidelines also describe the appropriate use of observation ("watchful waiting") versus active intervention in certain patients. After definitive therapy, patients should be monitored with PSA determinations, digital rectal examination, and bone scans, as outlined in the guidelines. Patients who exhibit increasing PSA levels after prostatectomy are candidates for salvage therapy with androgen ablation, radiotherapy, or observation. If PSA levels begin to increase after radiotherapy, surgery may then be an additional option. Systemic salvage therapy generally consists of androgen ablation; the benefit of total androgen blockade versus initial monotherapy remains controversial. Relapse after initial androgen ablation is treated with an antiandrogen, if none had been administered previously. Patients refractory to further hormonal manipulations are observed or receive palliative therapy, including chemotherapy. The treatment of prostate cancer is complex. Optimal treatment is risk-adapted to the specific characteristics of the cancer and the expected longevity and personal preferences of the patient.

Salvage cryotherapy for recurrent prostate cancer after radiotherapy: variables affecting patient outcome

PURPOSE

To determine the long-term disease-specific survival (DSS) and disease-free survival (DFS) rates after salvage cryotherapy for locally recurrent adenocarcinoma of the prostate and to identify pretreatment factors that have an impact on DSS and DFS.

PATIENTS AND METHODS

Between July 1992 and January 1995, 131 patients who had received definitive radiation therapy (XRT) underwent salvage cryotherapy for locally recurrent adenocarcinoma of the prostate. Cryotherapy failure was defined as an increasing postcryotherapy prostate-specific antigen (PSA) level of > or = 2 ng/mL above the postcryotherapy nadir, a positive prostate biopsy, or radiographic evidence of metastatic disease. Clinical variables were studied to determine whether there was an association with the DSS and DFS.

RESULTS

The median follow-up was 4.8 years. The 5-year DSS rates were 87% for patients with a precryotherapy Gleason score < or = 8 and 63% for those with Gleason scores of 9 and 10 (P =.012). The 5-year DFS rates were 57% for patients with a precryotherapy PSA level of < or = 10 ng/mL and 23% for those with a PSA level greater than 10 ng/mL (P =.0004). The 5-year DSS rates for patients with a pre-XRT clinical stage of T1 to T2 and those with a clinical stage of T3 to T4 were 94% and 72%, respectively (P =.0041). The 5-year DFS rates for these groups were 90% and 69%, respectively (P =.0057).

CONCLUSION

Androgen-independent local recurrences, Gleason score, and pre-XRT clinical stage were important factors that had an impact on DSS and DFS. The subset of patients cured by salvage cryotherapy seems to be small, and patient selection is important.

Preliminary toxicity and prostate-specific antigen response of a Phase I/II trial of neoadjuvant hormonal therapy, 103Pd brachytherapy, and three-dimensional conformal external beam irradiation in the treatment of locally advanced prostate cancer•

PURPOSE

Standard therapies for locally advanced prostate cancer have resulted in suboptimal disease control rates. A Phase I/II trial was designed for patients with positive seminal vesicle biopsies, prostate-specific antigen (PSA) >15 ng/ml, Gleason score > or =8 or clinical classification T2c-T3 to improve local control and to test the tolerance of the prostate to high-dose radiation by using neoadjuvant hormonal therapy, 103Pd brachytherapy, and conformal three-dimensional external beam radiation therapy (EBRT). This article outlines treatment-related morbidity and PSA response to this regimen and analyzes the effect of escalating doses of brachytherapy.

METHODS AND MATERIALS

Forth-three patients with T1c-T3 prostate cancer were enrolled in a Phase I/II trial from March 1994 through September 1997. Follow-up ranged from 12 to 64 months (median, 32 months). Pretreatment PSA ranged from 2.1 to 202 ng/ml (median, 16 ng/ml). Seventy-seven percent (33 of 43) of patients had high-grade tumors (score > or =7). Seventy-four percent (32 of 43) had stage > or =T2c. A total of 21 (49%) patients had positive seminal vesicle biopsies. Treatment consisted of hormonal therapy for 3 months with leuprolide and flutamide followed by a 103Pd implant and, 2 months later, 59.4 Gy of three-dimensional EBRT. Hormonal therapy was continued for 9 months. The planned 103Pd dose was escalated from 57 Gy (13 patients) to 77 Gy (13 patients) to 86 Gy (17 patients).

RESULTS

The actuarial freedom from PSA failure (PSA>0.5 ng/ml) at 4 years was 74%. There were no significant differences found when analyzing patients by presenting PSA or seminal vesicle status. There was a trend toward improved outcome with higher doses delivered to the prostate via the implant. Patients receiving doses > or =65 Gy (31 patients) had a freedom from PSA failure rate at 4 years of 89.5%, compared with 52.5% for those receiving doses <65 Gy (10 patients; p=0.08). The last PSA values for those patients free from PSA failure were < or =0.1 ng/ml in 25 (69%), >0.1-0.2 ng/ml in 5 (14%), and >0.2-0.5 ng/ml in 6 (17%). The actuarial freedom from developing Grade 2 proctitis was 75% at 4 years. There was a trend toward increased proctitis with increasing prostate implant doses. Patients with doses < or =70 Gy (n=12) had a 92% freedom from Grade 2 proctitis compared with 67.5% for those with doses delivered to 90% of the gland from a dose-volume histogram of >70 Gy (n=29) (p=0.15). There were no cases of Grade 3 or 4 proctitis. The 3-year actuarial preservation of sexual potency rate was 43%.

CONCLUSIONS

The preliminary results from this regimen show an improvement in PSA control for this group of locally advanced prostate cancer patients over more standard therapies. To maximize control while minimizing toxicity, doses of 65-70 Gy of 103Pd should be used when 59.4 Gy of three-dimensional EBRT is delivered. Longer follow-up will be needed to further substantiate these findings.

High-dose-rate brachytherapy in the treatment of carcinoma of the prostate

BACKGROUND

Although radical prostatectomy for localized disease is considered as a standard of care, external-beam radiotherapy and brachytherapy are equally effective. We report on the technique and preliminary results of high-dose-rate (HDR) brachytherapy using a temporary iridium-192 implant technique.

METHODS

The authors reviewed the literature on the techniques, treatment protocols, and results of HDR brachytherapy in the treatment of carcinoma of the prostate, and they report their own protocols, technique, and results.

RESULTS

The combination of HDR brachytherapy and external irradiation has been well tolerated by all 200 patients in our series, with less than 3% grade 3 late complications and with 95% PSA relapse-free survival with a median follow-up of 24 months.

CONCLUSIONS

HDR brachytherapy may be the most conformal type of irradiation in the treatment of carcinoma of the prostate regardless of tumor size, anatomical distortion, and organ mobility.

Early growth response-1 gene: potential radiation response gene marker in prostate cancer

This study was undertaken to determine whether the transcription factor EGR-1 expression: (1) in the primary tumor, correlates with radiation response in terms of complete local tumor control with no evidence of disease or recurrence and no evidence of metastasis; (2) in the postirradiated biopsies correlates with residual tumor; and (3) correlates with the expression of Egr-1 target genes such as TP53, pRB, and Bax. The authors analyzed: (1) 25 pretreated surgically resected paraffin-embedded primary adenocarcinomas of the prostate for the presence of EGR-1 expression and mutation, and correlated this with clinical endpoints such as serum prostate-specific antigen levels and current clinical status; (2) 27 postirradiated biopsies of prostate for the presence of EGR-1 expression, and correlated these findings to the residual tumor status; and (3) 12 prospective prostate tumor specimens for EGR-1 expression and its target genes. EGR-1 expression was determined by immunohistochemistry and mutations were screened in two regions of the Egr-1 gene (trinucleotide AGC repeats in transactivation domain [TD] and poly A tract in 3'UTR) by polymerase chain reaction-single strand conformational polymorphism analysis. Of 25 patients, 18 patients showed expression of EGR-1. EGR-1 overexpression correlated with treatment failure. No correlation with EGR-1 overexpression and its target genes was found, which may indirectly suggest that overexpressed EGR-1 may lack transactivation function. In summary, EGR-1 overexpression in the mutant form may provide an indication of clinical failure (local recurrence or metastasis).

Salvage radical prostatectomy after radiation therapy and brachytherapy

Local recurrence after any type of radiation therapy presents the clinician with a significant challenge. If there is no evidence of metastatic disease, patients can be offered a potentially curative salvage prostatectomy. To qualify for such surgery, patients should be at least 12 months from the completion of radiation and have at least a 10-year life expectancy; ideally, they will have a serum prostate specific antigen concentration <10 ng/mL and a Gleason score of 7 or less. Perioperative complications are substantial, with urinary incontinence rates of 40% to 50% and rectal injury rates of 10% to 15%. Long-term disease-free survival rates of 30% to 40% can be expected.

Interim report of image-guided conformal high-dose-rate brachytherapy for patients with unfavorable prostate cancer: the William Beaumont phase II dose-escalating trial

PURPOSE

We analyzed our institution's experience treating patients with unfavorable prostate cancer in a prospective Phase II dose-escalating trial of external beam radiation therapy (EBRT) integrated with conformal high-dose-rate (HDR) brachytherapy boosts. This interim report discusses treatment outcome and prognostic factors using this treatment approach.

METHODS AND MATERIALS

From November 1991 through February 1998, 142 patients with unfavorable prostate cancer were prospectively treated in a dose-escalating trial with pelvic EBRT in combination with outpatient HDR brachytherapy at William Beaumont Hospital. Patients with any of the following characteristics were eligible: pretreatment prostate-specific antigen (PSA) >/= 10.0 ng/ml, Gleason score >/= 7, or clinical stage T2b or higher. All patients received pelvic EBRT to a median total dose of 46.0 Gy. Pelvic EBRT was integrated with ultrasound-guided transperineal conformal interstitial iridium-192 HDR implants. From 1991 to 1995, 58 patients underwent three conformal interstitial HDR implants during the first, second, and third weeks of pelvic EBRT. After October 1995, 84 patients received two interstitial implants during the first and third weeks of pelvic EBRT. The dose delivered via interstitial brachytherapy was escalated from 5.50 Gy to 6.50 Gy for each implant in those patients receiving three implants, and subsequently, from 8.25 Gy to 9.50 Gy per fraction in those patients receiving two implants. To improve implant quality and reduce operator dependency, an on-line, image-guided interactive dose optimization program was utilized during each HDR implant. No patient received hormonal therapy unless treatment failure was documented. The median follow-up was 2.1 years (range: 0.2-7.2 years). Biochemical failure was defined according to the American Society for Therapeutic Radiology and Oncology Consensus Panel definition.

RESULTS

The pretreatment PSA level was >/= 10.0 ng/ml in 51% of patients. The biopsy Gleason score was >/= 7 in 58% of cases, and 75% of cases were clinical stage T2b or higher. Despite the high frequency of these poor prognostic factors, the actuarial biochemical control rate was 89% at 2 years and 63% at 5 years. On multivariate analysis, a higher pretreatment PSA level, higher Gleason score, higher PSA nadir level, and shorter time to nadir were associated with biochemical failure. In the entire population, 14 patients (10%) experienced clinical failure at a median interval of 1.7 years (range: 0.2-4.5 years) after completing RT. The 5-year actuarial clinical failure rate was 22%. The 5-year actuarial rates of local failure and distant metastasis were 16% and 14%, respectively. For all patients, the 5-year disease-free survival, overall survival, and cause-specific survival rates were 89%, 95%, and 96%, respectively. The 5-year actuarial rate of RTOG Grade 3 late complications was 9% with no patient experiencing Grade 4 or 5 acute or late toxicity.

CONCLUSION

Pelvic EBRT in combination with image-guided conformal HDR brachytherapy boosts appears to be an effective treatment for patients with unfavorable prostate cancer with minimal associated morbidity. Our dose-escalating trial will continue.

Treatment of locally advanced prostate cancer: is chemotherapy the next step?

PURPOSE

Management of locally advanced prostate cancer remains controversial. Various single and combination modality approaches have been advocated, but an accepted standard of care remains undefined. The purpose of this review is to define the current knowledge in managing locally advanced prostate cancer and to propose new treatment approaches based on current knowledge.

MATERIALS AND METHODS

A MEDLINE search to detect all relevant articles on the management of locally advanced prostate cancer was performed. A review of the staging, natural history, and prognosis of this disease was also performed.

RESULTS

The lack of a clearly defined treatment approach to patients with locally advanced prostate cancer stems from multiple factors, including ambiguities in clinical staging, inadequate knowledge of the natural history of the cancer, and a dearth of comparative randomized trials evaluating efficacy of different therapies. Single modality treatment, including radical prostatectomy (RP) or external-beam radiotherapy alone, is associated with high rates of failure. The use of adjuvant hormonal ablation therapy in combination with external-beam radiotherapy has shown improvement in progression-free and overall survival, although similar improvements have not been clearly demonstrated for surgical patients treated with hormonal therapy. New advances in chemotherapy for hormone-refractory prostate cancer suggest that response rates may be as high as 50% or more, and current trials are evaluating the addition of chemotherapy to hormonal ablation in either surgery or radiation therapy in locally advanced prostate cancer.

CONCLUSION

Optimal management of locally advanced prostate cancer remains undefined. Standard treatment options include RP, external-beam radiotherapy, or hormonal ablation therapy, alone or in combination. New approaches being tested include improved methods for delivering radiation or combining hormonal ablation with surgery or radiation. It is possible that other forms of systemic therapy, including chemotherapy, may become important components of multimodality treatment. Clinical trials designed to test this hypothesis are ongoing.

Histopathologic effects of three-dimensional conformal external beam radiation therapy on benign and malignant prostate tissues

We reviewed 137 prostate sextant needle biopsies from 137 patients obtained at a median of 35.7 months after three-dimensional conformal external beam radiation therapy (3DCRT). Thirty-one patients (23%) received 3 months of androgen deprivation therapy (ADT) before 3DCRT. We also retrospectively reviewed and assigned a combined Gleason score to the pre-3DCRT needle biopsies (97 patients) or transurethral resection of the prostate gland (1 patient). High-molecular-weight cytokeratin (34betaE12) and prostate-specific antigen (PSA) immunohistochemistry was performed in select cases. After 3DCRT, histopathologic changes in benign prostate gland consisted of glandular atrophy, cytologic atypia, and basal cell prominence. The benign glands showed intensely positive reactions with antibodies to high-molecular-weight cytokeratin (34betaE12) and negative to weakly positive reactions to PSA. Paneth cell-like change was seen in 44 (32%) of the biopsies, mucinous metaplasia in 29 (21%), luminal blue-tinged mucinous secretions in 14 (10%), and squamous metaplasia in 8 (6%). The changes in benign prostate tissues were similar between patients treated with ADT and 3DCRT and those treated with 3DCRT alone. After 3DCRT, we recognized two histologic patterns of prostate cancer: (1) prostate cancer showing radiation therapy (RT)-related changes characterized by PSA-positive/34betaE12-negative poorly formed glands or individual cells with abundant clear to finely granular cytoplasm, and (2) prostate cancer showing no apparent RT effect. High-grade prostatic intraepithelial neoplasia (PIN) was seen in 12 post-3DCRT biopsies (8.8%). The use of neoadjuvant ADT had a significant impact on the results of post-RT biopsy. Of the 31 patients treated with neoadjuvant ADT and 3DCRT, 3 (10%) had post-3DCRT biopsies showing prostate cancer without RT effect compared to 44 of 106 men (41%) treated with 3DCRT alone (p = 0.004). Compared to the Gleason score pre-RT, the Gleason score of cancers showing no RT effect was the same in 25 patients (71%), +/-1 point in 8 patients (23%), and +2 points in 2 patients (6%). The mean combined Gleason score post-RT was slightly, although significantly, higher than that pre-RT (7.29 +/- 0.71 versus 7.00 +/- 0.59, p = 0.01). Serum PSA at the time of post-3DCRT biopsy correlated with biopsy results. Prostate cancer without therapy effect was seen in only one of 43 patients (2%) with a serum PSA level < or = 1 ng/ml compared to 46 of 94 patients (49%) with a PSA level > 1 ng/ml (p = 0.0001). After 3DCRT, benign prostate glands show profound histopathologic changes and may be confused with prostate cancer. The effects of 3DCRT on prostate cancer are variable, with some cases showing profound therapy-related changes and others showing no apparent therapy effect.

Patient selection for salvage cryotherapy for locally recurrent prostate cancer after radiation therapy

PURPOSE

Our objective was to identify clinical pretreatment factors associated with early treatment failure after salvage cryotherapy.

PATIENTS AND METHODS

Between 1992 and 1995, 145 patients underwent salvage cryotherapy for locally recurrent adenocarcinoma of the prostate. Treatment failure was defined as an increasing postcryotherapy serial prostate-specific antigen (PSA) level of more than or equal to 2 ng/mL above the postcryotherapy nadir or as a positive posttreatment biopsy. We evaluated the following factors as predictors of treatment failure: tumor stage and grade at initial diagnosis, type of prior therapy, stage and grade of locally recurrent tumor, number of positive biopsy cores at recurrence, and precryotherapy PSA level.

RESULTS

Among patients with a prior history of radiation therapy only, the 2-year actuarial disease-free survival (DFS) rates were 74% for patients with a precryotherapy PSA less than 10 ng/mL and 28% for patients with a precryotherapy PSA more than 10 ng/mL, P <.00001. The DFS rates were 58% for patients with a Gleason score of less than or equal to 8 recurrence and 29% for patients with a Gleason score greater than or equal to 9 recurrence, P <.004. Among patients with a precryotherapy PSA less than 10 ng/mL, DFS rates were 74% for patients with a prior history of radiation therapy only and 19% for patients with a history of prior hormonal therapy plus radiation therapy, P <.002.

CONCLUSION

Patients failing initial radiation therapy with a PSA more than 10 ng/mL and Gleason score of the recurrent cancer more than or equal to 9 are unlikely to be successfully salvaged. Patients failing initial hormonal therapy and radiation therapy are less likely to be successfully salvaged than patients failing radiation therapy only.

Fast neutrons in prostatic adenocarcinomas: worldwide clinical experience

Primary tumor control remains a major problem in the treatment of locally advanced prostate carcinoma. Clinical local failure rates approach 30-40% and may be significantly higher when results of prostatic biopsy or prostate-specific antigen (PSA) levels are considered. The low growth rate and cycling fraction of prostate adenocarcinoma suggest potential therapeutic advantage for the high linear energy transfer (LET) of neutrons. The Radiation Therapy Oncology Group (RTOG) performed a multi-institutional randomized trial (RTOG 77-04) comparing mixed beam (neutron plus photon) irradiation to conventional photon irradiation for the treatment of locally advanced prostate cancer. A subsequent trial by the Neutron Therapy Collaborative Working Group (NTCWG 85-23) compared pure neutron irradiation to standard photon irradiation. Both randomized trials demonstrate significant improvement in locoregional control with neutron irradiation compared to conventional photon irradiation in the treatment of locally advanced prostate carcinoma. To date, only the mixed beam trial has shown a significant survival benefit. Future analysis of the larger NTCWG trial at the 10-year point should confirm whether or not improved locoregional control translates into a survival advantage. These findings have significant implications for all local treatment strategies including dose-escalated conformal photon irradiation, prostate implantation, and neutron radiation. Given the large numbers of patients afflicted with this disease, a positive survival advantage for neutrons or mixed beam therapy would provide a strong incentive for the development of economically feasible clinical neutron facilities.

Dose escalation with three-dimensional conformal radiation therapy affects the outcome in prostate cancer

PURPOSE

Three-dimensional conformal radiation therapy (3D-CRT) is a technique designed to deliver prescribed radiation doses to localized tumors with high precision, while effectively excluding the surrounding normal tissues. It facilitates tumor dose escalation which should overcome the relative resistance of tumor clonogens to conventional radiation dose levels. The present study was undertaken to test this hypothesis in patients with clinically localized prostate cancer.

METHODS AND MATERIALS

A total of 743 patients with clinically localized prostate cancer were treated with 3D-CRT. As part of a phase I study, the tumor target dose was increased from 64.8 to 81 Gy in increments of 5.4 Gy. Tumor response was evaluated by post-treatment decrease of serum prostate-specific antigen (PSA) to levels of < or = 1.0 ng/ml and by sextant prostate biopsies performed > or = 2.5 years after completion of 3D-CRT. PSA relapse-free survival was used to evaluate long-term outcome. The median follow-up was 3 years (range: 1-7.6 years).

RESULTS

Induction of an initial clinical response was dose-dependent, with 90% of patients receiving 75.6 or 81.0 Gy achieving a PSA nadir < or = 1.0 ng compared with 76% and 56% for those treated with 70.2 Gy and 64.8 Gy, respectively (p < 0.001). The 5-year actuarial PSA relapse-free survival for patients with favorable prognostic indicators (stage T1-2, pretreatment PSA < or = 10.0 ng/ml and Gleason score < or = 6) was 85%, compared to 65% for those with intermediate prognosis (one of the prognostic indicators with a higher value) and 35% for the group with unfavorable prognosis (two or more indicators with higher values) (p < 0.001). PSA relapse-free survival was significantly improved in patients with intermediate and unfavorable prognosis receiving > or = 75.6 Gy (p < 0.05). A positive biopsy at > or = 2.5 years after 3D-CRT was observed in only 1/15 (7%) of patients receiving 81.0 Gy, compared with 12/25 (48%) after 75.6 Gy, 19/42 (45%) after 70.2 Gy, and 13/23 (57%) after 64.8 Gy (p < 0.05).

CONCLUSIONS

The data provide evidence for a significant effect of dose escalation on the response of human prostate cancer to irradiation and defines new standards for curative radiotherapy in this disease.

Three-dimensional conformal radiotherapy and dose escalation: where do we stand?

Three-dimensional conformal radiotherapy is an effective means of delivering high doses of radiation with enhanced precision. Several institutions have gained substantial experience using this modality for patients with clinically localized prostate cancer. Reports from these centers have demonstrated not only excellent tolerance despite the administration of higher radiation doses, but improved biochemical and local control outcomes as well. Meticulous attention to treatment technique and dose volume histogram analysis are critical for the safe implementation of these higher doses. The emergence of intensity-modulated treatment planning has provided the opportunity at our institution to further escalate the radiation dose to 86.4 Gy while still respecting the surrounding normal tissue tolerance. Phase I studies will need to continue to define more clearly the maximal dose of radiation that can be delivered safely with this modality. Current studies indicate a direct correlation between dose and prostate-specific antigen (PSA) relapse-free survival response for patients with intermediate and high-risk prognostic features. These patients likely represent the ideal cohort for future studies designed to investigate the impact of dose on biochemical and disease-free survival outcome.

Value of sextant biopsies in the assessment of local cure following external beam radiotherapy of prostatic adenocarcinoma

Between 1982 and 1992, 73 patients received radical external beam radiotherapy (EBR) for prostatic adenocarcinoma at the Central Hospital, Västerås, with an average dose of 68.1 Gy (range 64.5-72.5 Gy) and an average cumulative radiation effect (CRE) of 18.2 (range 17.1-19.9) All patients had a negative bone scan prior to treatment and presented with clinical stage T1-T4,Nx,Mo. Twenty-four out of 36 surviving patients consented to participate in a follow-up study which included transrectal, ultrasonically guided prostate biopsies. The average follow-up from EBR to biopsy was 5.5 years (range 3.6-11.1 years). Sixteen (67%) of the patients had a positive biopsy. The average PSA level in the biopsy-positive group was 35.7 ng/mL (range 3.9-200 ng/mL). In the biopsy-negative group, the average PSA was 3.7 ng/mL (range 0.2-13.0 ng/mL). The conclusion is that the degree of local cure achieved in patients with prostatic cancer treated with external beam radiotherapy is low (33%), and that a higher radiation dose may be required to eradicate this malignancy.

Percutaneous transperineal radiofrequency ablation of prostate tumour: safety, feasibility and pathological effects on human prostate cancer

OBJECTIVE

To evaluate the safety of radiofrequency (RF) energy delivered interstitially in patients with prostate cancer scheduled for radical prostatectomy and to correlate the proposed theoretical lesion size with the pathological findings.

PATIENTS AND METHODS

Radiofrequency interstitial tumour ablation (RITA) was performed in 15 patients with localized prostate cancer before radical surgery. RF energy was delivered to the prostate by active needle electrodes (monopolar or bipolar) placed transperineally under transrectal ultrasonography guidance. Needle electrodes were used with different configurations and in some cases were covered by retractable shields to vary the length and circumference of the thermal lesions created. In eight patients, the procedure was performed immediately before radical prostatectomy, in six RITA was performed under spinal anaesthesia 1 week before surgery and in one patient, no surgery was performed but the patient was followed by serial determinations of prostate specific antigen (PSA). At least two lesions were created in each prostate, including both capsule and peripheral zones. NADPH and haematoxylin & eosin (H&E) staining were used to assess the extent of the necrotic lesion in the radical prostatectomy specimen.

RESULTS

The mean energy delivered was 10.5 kJ, with central temperatures reaching up to 105 degrees C during 12 min of ablation; rectal temperature remained at < 38 degrees C. There were no complications. Macroscopic examination showed well-demarcated lesions including the prostatic capsule, up to 2.2 x 1.5 x 4.5 cm. With monopolar energy, the observed lesion size was comparable to the predicted 2 x 2 x 2 cm lesion, while with bipolar energy, lesion size was related to interneedle distance and uncovered needle length. Microscopic examination showed clearly delineated lesions both with NADPH (in prostates immediately removed after surgery) and H&E (at 1 week after RITA) staining. The lesion size observed on pathological analysis correlated with the predicted lesion size. In one patient, no residual cancer was found in the specimen. In the patient whose entire prostate was targeted and followed by serial PSA measurements, the latter were undetectable at 3 months of follow-up.

CONCLUSION

Transperineally delivered RF energy is capable of safely creating extensive coagulative necrotic lesions in prostate cancer tissue, in a reproducible and controlled manner. The results presented here provide basic information for the potential future application of this form of energy for localized prostate cancer.

Preliminary outcomes following cryosurgical ablation of the prostate in patients with clinically localized prostate carcinoma

PURPOSE

Cryosurgical ablation of the prostate is a novel therapeutic modality that induces cell lysis in the prostate by direct application of low temperatures. We have been conducting an ongoing prospective pilot study of the use of cryosurgical prostate ablation in treating patients with nonmetastatic prostate adenocarcinoma since January 1993. Results in 145 consecutive patients with mean 36 months and minimum 12 months of followup are presented.

MATERIALS AND METHODS

Accrual was open to patients with clinical stages T1a to T3c prostate adenocarcinoma. Pelvic lymph node dissections were recommended but not required for patients with prostate specific antigen (PSA) greater than 15 ng./ml. before study entry. PSA changes, random prostate biopsy findings and morbidities after cryosurgical prostate ablation were recorded for each patient.

RESULTS

Overall actuarial rates at 42 months for maintaining PSA less than 0.3 and less than 1.0 were 59% and 66%, respectively. The overall actuarial progression-free rate at 60 months was 56%. Among 160 biopsies performed 16% showed some evidence of residual carcinoma. Overall crude rates of maintaining either a negative biopsy or PSA less than 0.3 at 6 and 24 months after cryosurgical prostate ablation were 87% and 73%, respectively. Significantly higher morbidities were seen in previously radiated patients undergoing cryosurgical prostate ablation compared to those with no prior radiation. Among nonradiated patients 85% experienced no significant morbidity after cryosurgical prostate ablation.

CONCLUSIONS

Although preliminary, short-term outcomes after cryosurgical prostate ablation appear to be comparable to identical outcomes reported for external beam radiotherapy. Based on these results cryosurgical prostate ablation appears to be an effective therapeutic alternative for treating patients with localized prostate adenocarcinoma.

Gold seed implantation in prostate brachytherapy

Interstitial brachytherapy for treatment of prostate cancer with radioactive gold--initially with liquid gold and later with seed technique--is based on an experience of more than four decades. With biopsy results approaching a 80% negative rate, and, at 5 years, a cancer specific survival of 100% for Stages A and B1, 90% for Stage B2, and 76% for Stage C, this form of treatment offers an effective and well-tolerated alternative mode of therapy for patients with localized prostate cancer.

Combined treatment with temporary short-term high dose rate iridium-192 brachytherapy and external beam radiotherapy for irradiation of localized prostatic carcinoma

PURPOSE

To evaluate the treatment outcome after radical radiotherapy of localized prostate cancer in 50 patients (38 patients with stage T1-2 and 12 patients with stage T3) after a median follow-up time of 45 months (range 18-92 months).

METHODS

The treatment was given by combination of external beam radiotherapy (50 Gy) and brachytherapy (2 x 10 Gy). The brachytherapy was given using TRUS-guided percutaneously inserted temporary needles with a high dose rate remote afterloading technique with Ir-192 as the radionuclide source. Three target definitions and dose levels inside the prostate gland were used. Local control was evaluated by digital rectal examination, TRUS-guided biopsies and serum PSA evaluations.

RESULTS

Clinical and biopsy verified local control was achieved in 48 of the 50 (96%) patients; for stage T1-2 in 37 of 38 (97%) patients and for stage T3 in 11 of 12 (92%) patients. A posttreatment serum PSA level < or =1.0 ng/ml was seen in 42 (84%) patients, values from >1.0 to < or =2.0 ng/ml were seen in four (8%) patients and values exceeding 2.0 were seen in four (8%) patients. The late toxicity was minimal.

CONCLUSION

The local control results and the minimal toxicity after the combined radiotherapy treatment are promising. However, long term results are necessary before general use.

Neoadjuvant androgen suppression with radiation in the management of locally advanced adenocarcinoma of the prostate: experimental and clinical results

Conventional radiotherapy has been a standard treatment for the management of locally advanced T2c-4 prostatic carcinoma for over 2 decades. The routine use of serum PSA in follow-up makes it clear that > 80% of these patients will show evidence of failure by 10 years. Rebiopsy of those with a rising PSA shows locally persistent disease in the majority of cases. Increasing the radiation dose applied to the prostate increases local control but at the risk of higher morbidity. Experimental data using the Shionogi tumor mouse model suggest a potential gain from neoadjuvant androgen suppression without any increase in normal tissue morbidity. Two randomized trials comparing neoadjuvant androgen suppression prior to radiation therapy with radiation alone in humans show considerable short-term gains in local control and disease-free survival but mature data are still awaited. It is currently unknown whether the positive interaction between radiation and androgen suppression is synergistic or simply additive.

Evaluating radical prostatectomy specimens: therapeutic and prognostic importance

The pathologic staging of prostate cancer involves determination of the anatomic extent and burden of tumor based on the best available data. Proper examination of radical prostatectomy specimens is critical in determining cancer stage, stratifying patient need for adjuvant treatment, and prediction of patient outcome. Differences exist in methods of handling and sampling specimens, although publication of practice protocols in recent years has led to convergence of opinion. In this report, we evaluate the current aspects of pathologic staging of prostate cancer and assessment of prostatectomy specimens. Recent international agreement on pathologic staging of prostate cancer should allow valid comparisons of surgical treatment from different institutions. The vanishing cancer phenomenon is also briefly discussed.

Assessment of proliferation indicators in residual prostatic adenocarcinoma cells after radical external beam radiotherapy

BACKGROUND

Fifty-five patients who had received radical external beam radiotherapy (RRT) for clinically staged, localized prostatic adenocarcinoma were examined with systematic sextant mapping with the help of transrectal ultrasound-guided core biopsies. The average follow-up after RRT was 6.8 years. Residual cancer was found histopathologically in 67% (37/55) of the patients investigated.

METHODS

In the present report, the viability of these tumor cells was studied using immunohistochemical staining methods with the monoclonal antibodies MIB1 and PC10, which are specific for the proliferation-associated antigens Ki-67 and PCNA.

RESULTS

Available data concerning proliferating activity in the pretreatment situation in 12 of these patients revealed that proliferating activity was substantially reduced in the majority of cases after RRT. Post-RRT, Ki-67, and PCNA activity was nonetheless found to varying degrees in 64% and 94% of the 36 evaluable tumor-harboring specimens, respectively. In the majority of cases, the proportion of proliferating cells, designated "score", was low. However, Ki-67 scores of up to 8% and PCNA scores of up to 50% were obtained in 35% (8/23) and 97% (33/34) of the specimens, respectively, with proliferative activity. There was no significant correlation between tumor grade and proliferative score in the follow-up biopsies. In the 36 cases investigated, endocrine treatment did not influence the proliferation results.

CONCLUSIONS

The present study demonstrates a proliferative capacity in residual tumor cells in a long-term follow-up after RRT, suggesting that these cancer cells might have a biological significance.

Treatment options for localized recurrence of prostate cancer following radiation therapy

Patients with radioresistant clinically localized prostate cancer may be treated by various means. Although androgen ablation is relatively noninvasive, it cannot be considered a curative option. We believe that a subset of patients with locally recurrent prostate cancer without subclinical metastatic disease exists and would benefit from maximally aggressive local therapy. Salvage surgery may offer long-term cancer control, particularly when the tumor is organ-confined, but is a technically challenging operation with a high incidence of postoperative incontinence. Cryoablation of the prostate for postirradiation recurrence may offer a less invasive alternative to radical surgery, but its long-term efficacy remains to be fully determined. Each therapeutic option has its characteristic attendant morbidity and the choice of therapy for local recurrence should be made with informed consent after frank discussion between physician and patient. We propose the treatment algorithm shown in Figure 1 for the management of patients with suspected recurrence after radiation therapy with the caveat that individual therapeutic strategies must be patterned around individual patient needs.

Should asymptomatic progression following definitive local treatment for prostate cancer be treated?

Asymptomatic progression following definitive therapy for prostate cancer can take the form of a detectable prostate-specific antigen (PSA) or local recurrence following radical prostatectomy or a rising PSA or palpable recurrence following radiotherapy. Options for treatment include hormonal therapy, radiotherapy, salvage surgery, and experimental therapies. Although such forms of treatment have known effects on intermediate endpoints, such as reduction of PSA, the overall effect on survival and quality of life is uncertain.