Stage T1-2 prostate cancer with pretreatment prostate-specific antigen level < or = 10 ng/ml: radiation therapy or surgery?

Stereotactic body radiotherapy for low-risk prostate cancer: five-year outcomes

Purpose

Hypofractionated, stereotactic body radiotherapy (SBRT) is an emerging treatment approach for prostate cancer. We present the outcomes for low-risk prostate cancer patients with a median follow-up of 5 years after SBRT.

Method and Materials

Between Dec. 2003 and Dec. 2005, a pooled cohort of 41 consecutive patients from Stanford, CA and Naples, FL received SBRT with CyberKnife for clinically localized, low-risk prostate cancer. Prescribed dose was 35-36.25 Gy in five fractions. No patient received hormone therapy. Kaplan-Meier biochemical progression-free survival (defined using the Phoenix method) and RTOG toxicity outcomes were assessed.

Results

At a median follow-up of 5 years, the biochemical progression-free survival was 93% (95% CI = 84.7% to 100%). Acute side effects resolved within 1-3 months of treatment completion. There were no grade 4 toxicities. No late grade 3 rectal toxicity occurred, and only one late grade 3 genitourinary toxicity occurred following repeated urologic instrumentation.

Conclusion

Five-year results of SBRT for localized prostate cancer demonstrate the efficacy and safety of shorter courses of high dose per fraction radiation delivered with SBRT technique. Ongoing clinical trials are underway to further explore this treatment approach.

Surgery Versus Implant for Early Prostate Cancer: Results From a Single Institution, 1992–2005

PURPOSE

The aim of this study was to compare the biochemical disease-free survival rates for radical prostatectomy versus transperineal ultrasound-guided prostate implant for patients with early prostate cancer treated at a single institution from 1992 through 2005.

MATERIALS AND METHODS

The charts of 741 patients with early prostate cancer (350 implant and 391 surgery) treated from 1992 through 2005 were retrospectively reviewed. Surgery patients were treated by members of the academic Urology Section at Yale University School of Medicine. Implant patients were treated by a combined team from the Urology Section and the Department of Therapeutic Radiology at Yale Medical School. For the 350 implant patients, 35% were treated with iodine-125 and 65% with palladium-103. Of the implant patients 92% were treated with an implant alone and 8% with combined external beam radiation therapy plus an implant and 25% received short-term hormone therapy to downsize the prostate before the implant. Both surgery and implant patients were analyzed based on a group with favorable cancers (clinical stage T1c or T2, prostate-specific antigen <10, and Gleason score <7), an intermediate group (any 1 factor increased compared with the favorable group), and a poor group (any 2 factors increased compared with the favorable group). The follow-up time varied from 12 to 120 months with a mean/median follow-up time of 44 months/42 months for implant patients and 42 months/40 months for surgery patients. Prostate-specific antigen recurrence for surgery was defined as any detectable prostate-specific antigen after surgery. Prostate-specific antigen recurrence for implant was defined as the prostate-specific antigen nadir plus 2 ng/mL after implant. The biochemical disease-free survival rates were calculated using the life-table method.

RESULTS

The 5-year biochemical disease-free survival rates for radical prostatectomy versus implant were identical for the favorable group (93% versus 92%), intermediate group (70% versus 70%), and poor group (50% versus 52%) patients.

CONCLUSIONS

From 1992 through 2005, implant therapy produced equivalent 5-year biochemical disease-free survival rates compared with surgery in patients with early prostate cancer treated at a single institution.

Results of radiation therapy combined with neoadjuvant hormonal therapy for stage III prostate cancer: comparison of two different definitions of PSA failure

BACKGROUND

We herein report the clinical outcome of radical radiation therapy combined with neoadjuvant hormonal therapy (NHT) for stage III (International Union Against Cancer [UICC] 1997: UICC 97) prostate cancer. Prostate-specific antigen (PSA) failure-free survival was assessed according to two different definitions, and the appropriateness of each definition is discussed.

METHODS

Between October 1997 and December 2000, 27 patients with stage III prostate cancer were enrolled in this study. The median pretreatment PSA level was 29 ng/ml (range, 7.4-430 ng/ml). The Gleason score (GS) was 7 or more in 22 patients (81%). All patients received 3 months of NHT with a luteinizing hormone-releasing hormone (LH-RH) analogue, in combination with an antiandrogen (flutamide), given during the first 2 weeks, followed by 70-Gy external-beam radiation therapy (EBRT) in 35 fractions. The initial 46 Gy was given with a four-field technique, while the remainder was given with a dynamic conformal technique. No adjuvant hormonal therapy (AHT) was given.

RESULTS

The median follow-up time was 63 months. PSA levels decreased to the normal range (<4 ng/ml) after irradiation in all but one patient. The 5-year PSA failure-free survival was 34.8% according to the American Society for Therapeutic Radiology and Oncology (ASTRO) definition and it was 43.0% according to the "nadir plus 2" definition. Discordance of the results between the two definitions was seen in two patients. The 5-year overall and cause-specific survivals were 83.0% and 93.3%, respectively. No severe acute or late adverse effects were observed.

CONCLUSION

Seventy Gy of EBRT following 3 months of NHT produced therapeutic results comparable to those reported in other studies which used long-term AHT. The value of long-term AHT for Japanese men should be tested in a clinical trial.

Biochemical (prostate-specific antigen) relapse-free survival and toxicity after125I low-dose-rate prostate brachytherapy

OBJECTIVE

To report our clinical experience and 5-year prostate-specific antigen (PSA) relapse-free survival rate for early-stage prostate cancer after (125)I low-dose-rate prostate brachytherapy.

PATIENTS AND METHODS

In all, 300 patients were treated between March 1999 and April 2003, and followed prospectively. Patients were stratified into low-, intermediate- and high-risk groups, and those receiving neoadjuvant androgen deprivation (NAAD) or not. Kaplan-Meier estimates of PSA relapse-free survival and PSA nadirs were obtained for all patients and for the risk groups. Toxicity, as urinary and erectile dysfunction (ED), were reported from a prospective database.

RESULTS

The median (range) follow-up was 45 (33-82) months. The actuarial PSA relapse-free survival was 93% at 5 years; 21 (7%) of patients had evidence of biochemical failure as defined by the American Society of Therapeutic Radiation Oncology criteria. There was no significant difference in actuarial survival for patients in the different risk groups, or between those receiving NAAD or not (low-risk 96%, intermediate 89%, high 93%, P = 0.12; NAAD 92%, no NAAD 95%, P = 0.30). Overall the 3-year median PSA level was 0.3 ng/mL (192 men). There was no significant difference in median 3-year PSA levels for different risk groups, or for those treated with or with no NAAD. The 3- and 4-year PSA nadir of <0.5 ng/mL was achieved by 71% and 86% of men, respectively. The acute urinary retention rate was 7%; 5.6% of men developed urethral strictures requiring dilatation, while 2.7% required a transurethral resection of the prostate after implantation, for obstructive symptoms. Of patients with no ED before treatment, 62% had no ED at 2 years, and of these 60% used a phosphodiesterase inhibitor.

CONCLUSION

This prospective series confirms the excellent overall biochemical survival after (125)I brachytherapy; the treatment was tolerated well, with early and late urinary toxicity and ED similar to other published results.

Comparison of three radiotherapy treatment planning protocols of definitive external-beam radiation for localized prostate cancer

BACKGROUND

Three radiotherapy treatment planning (RTTP) protocols for definitive external-beam radiation for localized prostate cancer, designed and clinically applied at Kyoto University, were compared.

METHODS

Treatment plans were created according to three different RTTP protocols (old three-dimensional conformal radiotherapy [3D-CRT], new 3D-CRT, and intensity-modulated radiotherapy [IMRT]) on computed tomography (CT) data sets of five patients with localized prostate cancer. The dynamic-arc conformal technique was used in the 3D-CRT protocols. Differences in dose distribution were evaluated and compared based on dose-volume histogram (DVH) analyses.

RESULTS

The coverage of the clinical target volume (= prostate alone) was comparable among the three RTTP protocols. However, the average values for the percent volume that received at least 95% of the prescription dose (V95), the percent of the prescription dose covering 95% of the volume (D95), and the conformity index of the planning target volume (PTV) were 99%, 97%, and 0.88 for the IMRT; 93.9%, 94.5%, and 0.76 for the new 3D-CRT; and 59.6%, 82.9%, and 0.6 for the old 3D-CRT protocol, respectively. Inhomogeneity of doses to the PTV was larger with the IMRT protocol than with the new 3D-CRT protocol. Doses to both the rectal wall and bladder wall were almost comparable with the new 3D-CRT and IMRT protocols, but were lower with the old 3D-CRT protocol, due to the lowest prescription dose and incomplete dose coverage of the PTV.

CONCLUSION

The old 3D-CRT protocol could not achieve the goals for the PTV set in the IMRT protocol. The new 3D-CRT and IMRT protocols were generally comparable in terms of both the PTV coverage and normal tissue-sparing, although the IMRT protocol achieved the most conformal dose distribution to the PTV, in return for a larger, but acceptable, dose inhomogeneity.

Les thérapeutiques et la surveillance dans le cancer de la prostate et leurs implications sur l’imagerie

Multiple treatments are proposed to cure prostate carcinoma. Radical prostatectomy is the classical option for localized tumor. However radiotherapy can be proposed in such circumstances with the argument of a less invasive procedure with similar results. High Intensity Focalised Ultrasound (HIFU) is a new technique available for similar staging of the carcinoma with good results. Follow up is based on biological evaluation of PSA. Imaging studies are required only in cases of abnormal level. Endorectal Ultrasonography with biopsies is useful after radical surgery. Indications for MRI study is mainly to differentiate a localized from a general recurrence.

The efficacy of conventional external beam, three-dimensional conformal, intensity-modulated, particle beam radiation, and brachytherapy for localized prostate cancer

Technologic advances in radiation treatment planning and delivery have generated popular interest in the different radiation therapy techniques used in treating patients with localized prostate cancer. Throughout the past decade, high-energy (> 4 MV) linear accelerators have largely replaced Cobalt machines in external beam radiation therapy (EBRT) delivery. Conventional EBRT has been used to treat prostate cancer successfully since the 1950s. By switching to computed tomography-based planning, three-dimensional conformal radiation therapy provides better relative conformality of dose than does conventional EBRT. Intensity-modulated radiation therapy (IMRT) has further refined dose conformality by spreading the low-dose region to a larger volume. However, the potential long-term risks of larger volumes of normal tissues receiving low doses of radiation in IMRT are unknown. Particle-beam radiation therapy offers unique dose distributions and characteristics with higher relative biologic effect and linear energy transfer. Transperineal prostate brachytherapy offers the shortest treatment time with equivalent efficacy without significant risk of radiation exposure. The addition of hormonal therapy to radiation therapy has been shown to improve the outcome of radiation therapy.

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

PURPOSE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Surgery, brachytherapy, and external-beam radiotherapy for early prostate cancer

Patients diagnosed with early prostate cancer after 2000 can expect better outcomes from treatment than patients who were diagnosed in the 1980s and early 1990s. These improved outcomes are the result of stage migration, new technologies such as three-dimensional conformal radiotherapy (3DCRT) and intensity-modulated external-beam radiotherapy (IMRT), better implant techniques, and optimum use of hormone therapy. We review the outcomes for radical prostatectomy, permanent seed implant, 3DCRT, and IMRT. For patients with clinical stage T1c or T2 disease and a Gleason score of less than 8, 5-year biochemical disease-free survival is remarkably similar for all the above treatments. Furthermore, complication rates are acceptable for all these modalities. For patients with bulky T2-3 disease or a Gleason score of 8-10, hormone therapy plus 3DCRT or IMRT is an excellent treatment choice. Studies of radical prostatectomy show the most reliable long-term results, and the studies of external-beam radiotherapy have used the best scientific methods to assess efficacy. On the basis of current data, we recommend specific treatment options.

An interinstitutional and interspecialty comparison of treatment outcome data for patients with prostate carcinoma based on predefined prognostic categories and minimum follow-up

BACKGROUND

The optimal management of patients with clinically localized prostate carcinoma remains undefined due in part to the absence of well-designed, prospective, randomized trials. The current study was conducted to compare and contrast outcomes with different forms of therapy for patients with prostate carcinoma who were treated at several institutions using predefined prognostic categories.

METHODS

A retrospective study of 6877 men with prostate carcinoma who were treated between 1989 and 1998 at 7 different institutions with 6 different types of therapy was conducted. Five-year actuarial rates of prostate specific antigen (PSA) failure were calculated based on predefined prognostic categories, which included combinations of pretreatment PSA level, tumor stage, and Gleason score. In addition, outcome was calculated using consistent biochemical failure definitions and a minimum, median length of follow-up.

RESULTS

Substantial differences in outcome were observed for the same type of treatment and at the same institution, depending on the number of prognostic variables used to define treatment groups. However, estimates of 5-year PSA outcomes after all forms of therapy for low-risk and intermediate-risk patient groups were remarkably similar (regardless of the type of treatment) when all three pretreatment variables were used to define prognostic categories. For patients in high-risk groups, the 5-year PSA outcomes were suboptimal, regardless of the treatment technique used.

CONCLUSIONS

The current data suggest that interinstitutional and interspecialty comparisons of treatment outcome for patients with prostate carcinoma are possible but that results must be based on all major prognostic variables to be meaningful. Analyzed in this fashion, 5-year PSA results were similar for patients in low-risk and intermediate-risk groups, regardless of the form of therapy. Findings from prospective, randomized trials using survival (cause specific and overall) as the end point for judging treatment efficacy and longer follow-up will be needed to validate these findings and to identify the most appropriate management option for patients with all stages of disease.

Primary radiation therapy for localized prostate cancer

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

Pre-treatment nomogram for biochemical control after neoadjuvant androgen deprivation and radical radiotherapy for clinically localised prostate cancer

Phase III studies have demonstrated the clinical benefit of adding neo-adjuvant androgen deprivation to radical radiotherapy for clinically localised prostate cancer. We have developed a nomogram to describe the probability of PSA control for patients treated in this way. Five hundred and seventeen men with clinically localised prostate cancer were treated with 3-6 months of neo-adjuvant androgen deprivation and radical radiotherapy (64Gy in 32#) between 1988 and 1998. Median presenting PSA was 20 ng x ml(-1), and 56% of patients had T3/4 disease. Multivariate analysis of pre-treatment factors was performed, and a nomogram developed to describe PSA-failure-free survival probability. At a median follow-up of 44 months, 233 men had developed PSA failure. Presenting PSA, histological grade and clinical T stage were all highly predictive of PSA failure on multivariate analysis. The nomogram score for an individual patient is given by the summation of PSA (<10=0, 10-19=16, 20-49=44, > or =50=100), grade (Gleason 2-4=0, 5-7=44, 8-10=81) and T stage (T1/2=0, T3/4=35). For a nomogram score of 0, 50, 100 and 150 points the 2 year PSA control rate was 93, 87, 75 and 54%, and the 5 year PSA control rate was 82, 67, 44 and 18%. These results are comparable to those using surgery or higher doses of radical radiotherapy alone. The nomogram illustrates the results of multivariate analysis in a visually-striking way, and facilitates comparisons with other treatment methods.

Gene transfer into human prostate adenocarcinoma cells with an adenoviral vector: Hyperthermia enhances a double suicide gene expression, cytotoxicity and radiotoxicity

We have previously developed a recombinant adenovirus containing a fusion gene of Escherichia coli cytosine deaminase (CD) and herpes simplex virus type 1 thymidine kinase (HSV-1 TK) controlled by a cytomegalovirus (CMV) enhancer-promoter. This replication-incompetent adenovirus effectively transduced the CD-TK gene into human prostate adenocarcinoma DU-145 or PC-3 cells. Interestingly, heat shock at 41 degrees C for 4 hours elevated the level of CD-TK by approximately 5- to 20-fold at a multiplicity of infection (MOI) of 1. Heat-enhanced expression of CD-TK promoted cytotoxicity by 23-, 9-, or 47-fold in the presence of 50 microg/mL ganciclovir (GCV), 500 microg/mL 5-fluorocytosine (5-FC), or 50 microg/mL GCV+500 microg/mL 5-FC, respectively, at an MOI of 1. Moreover, there was an increase in radiosensitivity when adenovirus-infected cells were heated at 41 degrees C for 4 hours followed by irradiation in the presence of the prodrugs. Virus+heat+1 microg/mL GCV treatment increased radiosensitivity by a dose-modifying factor (DMF) of 2.2, whereas virus+heat+10 microg/mL 5-FC exposure resulted in a DMF of 2.3. Radiosensitization was clearly enhanced as a result of combined prodrug exposure (DMF=4.4). Our results suggest that the efficiency in expression of suicide genes from an adenoviral vector used for cytotoxic anticancer therapy could be improved by combining heat treatment with radiation therapy.

Comparison of biochemical disease-free survival of patients with localized carcinoma of the prostate undergoing radical prostatectomy, transperineal ultrasound-guided radioactive seed implantation, or definitive external beam irradiation

PURPOSE

This retrospective study compares the long-term biochemical disease-free survival for patients undergoing radical prostatectomy, transperineal ultrasound-guided (125)Iodine implantation, or external beam irradiation alone in a tertiary referral community-based hospital.

METHODS AND MATERIALS

Five hundred forty patients were available for evaluation, which included: external beam, 132; (125)I, 186; and radical prostatectomy, 222. For the 318 patients referred to the Department of Radiation Oncology, those with T3 disease underwent external beam irradiation while patients with T1 or T2 underwent (125) 0.2 ng/mL or if they had three consecutive increases in their PSA or an increase in their postoperative PSA warranting intervention with androgen ablation or external beam irradiation to the pelvis.

RESULTS

Patients were stratified by pretreatment risk groups predicting for post-treatment PSA recurrence. Patients were considered to be at a low or intermediate risk for recurrence if their clinical stage was T1c, T2a, T2b, pretreatment PSA level was </= 20 or their biopsy. Gleason score was </= 6, Patients were considered to be at high risk for failure if they were clinically stage T2c, T3, PSA at diagnosis > 20, or Gleason score was >/= 7. For 132 patients undergoing external beam irradiation, 28 of 37 low or intermediate risk obtained a 1 year nadir PSA of < 1 (76%) while 40% of high risk patients obtained nadir < 1. Of 186 patients undergoing (125)I, 112 of 147 low or intermediate risk (76%) obtained a nadir PSA < 1. Twenty of 39 (51%) high risk obtained a nadir PSA < 1. Of the 222 patients undergoing prostatectomy, 83 of 88 (94%) low or intermediate risk had undetectable levels of PSA at 1 year. One hundred seventeen of 134 (86%) were high risk and had undetectable levels of PSA at 1 year. The biochemical disease-free survival for patients with low or intermediate risk at 5 years is approximately 70% with no significant difference between those patients treated with radical prostatectomy, external beam, or (125)I. For those patients with high risk factors for recurrence, there is no significant difference between ultrasound-guided implant or external beam, but there is a significant improvement in biochemical disease-free survival with radical prostatectomy.

CONCLUSION

For patients with low or intermediate risk disease, external beam, ultrasound-guided (125)I, or a radical prostatectomy give comparable long-term biochemical disease-free survival. For patients with high risk disease, a radical prostatectomy provides a significantly improved biochemical disease-free survival. Our current protocols utilize androgen ablation in combination with conformal three-dimensional external beam irradiation or androgen ablation in conjunction with external beam irradiation and (103)Pd seed implantation for patients at high risk for extra capsular disease. It is too early to determine if this combination therapy will give results comparable to radical prostatectomy. For patients who obtain a 1 year nadir PSA of < 1, the biochemical disease-free survival is durable with little risk of subsequent recurrence.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Optimizing patient selection for dose escalation techniques using the prostate-specific antigen level, biopsy gleason score, and clinical T-stage

PURPOSE

Ideal candidates for 3D dose escalation conformal radiation or external beam + implant therapy are identified on the basis of the prostate-specific antigen (PSA) level, biopsy Gleason score, and the 1992 American Joint Commission Cancer (AJCC) clinical T-stage.

METHODS AND MATERIALS

The pathologic findings of 1742 men with clinical stage T1c,2 prostate cancer managed with a radical prostatectomy (RP) between 1990 and 1998 were subjected to a logistic regression multivariable analysis. The endpoints examined included pathologic organ-confined (OC), specimen-confined (SC), and margin (M) or seminal vesicle (SV) positive disease. SC disease was defined as extracapsular extension (ECE) with a negative surgical margin. The clinical factors tested included PSA level, biopsy Gleason score, and the 1992 AJCC clinical T-stage. PSA failure-free (bNED) survival was calculated according to the method of Kaplan and Meier.

RESULTS

Significant negative predictors of pathologic OC-disease or positive predictors of M+ or SV+ disease included a PSA > 10 ng/ml (p<0.0001), biopsy Gleason score < or =7 (p< or =0.0004), and > or =T2b disease (p< or =0.03). Only biopsy Gleason score 7 (p = 0.0006) and PSA 10-15 ng/ml (p = 0.04) were significant predictors of SC disease. The estimates of 5-year bNED survival were 80%, 62%, and 35% (p<0.0001) for patients having a low, intermediate, or high likelihood of having M+ or SV+ disease respectively.

CONCLUSIONS

Patients most likely to derive a survival benefit from the improved local control possible using dose escalation techniques were those who had both a low risk of having occult micrometastatic disease (<25% M+ or SV+) and a reasonable likelihood of remaining disease-free after RP (>50% 5-year bNED). These patients included those having T1c, 2a, PSA > 10-15 ng/ml, and biopsy Gleason < or =6 or T1c, 2a, 2b, PSA < or =10 ng/ml, and biopsy Gleason < or =7 prostate cancer.

Adenoviral transduction of a cytosine deaminase/thymidine kinase fusion gene into prostate carcinoma cells enhances prodrug and radiation sensitivity

Prostate tumor cells (PC-3) were transduced with defective, recombinant adenovirus containing a fusion gene encoding the Escherichia coli cytosine deaminase and herpes simplex virus type-1 thymidine kinase under the control of a cytomegalovirus promoter. Expression levels of the fusion protein were dependent on the multiplicity of infection used and incubation time following infection. PC-3 cells expressing this protein were sensitized to killing by the normally innocuous prodrugs 5-fluorocytosine and ganciclovir. In addition, radiation-induced killing was enhanced in virally infected cells in the presence of the prodrugs.

Prostate-specific antigen to predict outcome of external beam radiation for prostate cancer: Walter Reed Army Medical Center experience, 1988-1995

OBJECTIVES

To assess the ability of pretreatment and post-treatment prostate-specific antigen (PSA) measurements, clinical tumor stage, tumor grade, Gleason sum, race, age, and radiation dose to predict the recurrence of prostate cancer following external beam radiation therapy (XRT) since the introduction of PSA as a tumor marker at one tertiary care center.

METHODS

The recurrence of prostate cancer among 371 evaluable patients of 389 patients treated with XRT at Walter Reed Army Medical Center was analyzed using Kaplan-Meier survival methodology and Cox multivariable regression models. Serologic (PSA) recurrence was determined using three consecutive rises in PSA after a nadir value. Clinical recurrence was defined as local recurrence (palpable or positive biopsy) and/or distant (radiographically evident) recurrence. Mean and median follow-up is 40.2 and 39.4 months, respectively (range 3.0 to 89.5), and minimum follow-up is 18 months for patients who were alive at the time of analysis. No patient received adjuvant hormonal therapy. Potential prognostic factors evaluated are pretreatment PSA, PSA nadir, age, race, clinical tumor stage, tumor grade, Gleason sum, and radiation dose.

RESULTS

Of the 371 evaluable patients, 125 had disease recurrence. The Kaplan-Meier 5-year disease-free survival (DFS) rates for significant pretreatment variables in univariate analyses are as follows: pretreatment PSA less than 4 (79%), 4.1 to 10 (67%), 10.1 to 20 (57%), 20.1 to 50 (27%), and more than 50 (0%); for clinical tumor Stage T1a-T1c (84%), T2a-T2c (51 %), and T3-T4 (29%); for tumor grade well (58%), moderate (58%), and poor (30%). Four-year DFS rates for Gleason sum are 2 to 4 (82%), 5 (72%), 6 (56%), and 7 to 10 (48%). In multivariable Cox regression analysis with backward elimination of nonsignificant variables, age, race, tumor grade, and radiation dose were eliminated, leaving pretreatment PSA, clinical tumor stage, and Gleason sum as significant prognostic factors. Analysis of a Cox model that included nadir PSA as a time-dependent variable showed it to be the strongest prognostic factor variable in the analysis.

CONCLUSIONS

XRT remains a suitable treatment modality for patients with pretreatment PSA less than 20.0, clinical tumor Stages T1-T2, and Gleason sum 2 to 6 prostate cancer. Patients achieving a nadir value less than 0.5 have more durable treatment outcomes.

Update on the treatment of prostate cancer with external beam irradiation

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Radiation therapy or prostatectomy: an old conflict revisited in the PSA era. A radiation oncologist's viewpoint

A close examination of the outcomes for the radical treatment of prostate cancer in the prostate-specific antigen (PSA) era shows no clear advantage to radical prostatectomy over external-beam radiation. Both modalities are highly effective against small impalpable tumors of low Gleason grade and with PSA values less than 10 ng/mL. Both modalities struggle against all other stages of prostate cancer. Radiation and surgery are currently in states of rapid evolution, and the results emerging become quickly outdated. It is hoped that the newer, more aggressive approaches will help a significant number of patients, perhaps the majority, not currently being cured by radical therapy.

Radiation therapy versus radical prostatectomy in the PSA era: a urologist's view

In the absence of a randomized trial directly comparing outcomes in men with localized prostate cancer treated by radical prostatectomy with treatment by radiation therapy, only an approximate answer regarding the relative efficacies of these modalities can be achieved. However, retrospective studies which examined outcomes based on pretreatment parameters intrinsic to the tumors have demonstrated that when stratified by grade and prostate specific antigen (PSA), the rates of cancer control for these therapies are similar at 5 years posttreatment. These modalities differ in other important ways, including acute toxicity, patient satisfaction, posttreatment quality of life, and ease of salvage of treatment failures. A consideration of all of these factors is necessary to arrive at the appropriate choice of therapy for each patient.