Anatomic boundaries of the clinical target volume (prostate bed) after radical prostatectomy

PURPOSE

We sought to derive and validate an interdisciplinary consensus definition for the anatomic boundaries of the postoperative clinical target volume (CTV, prostate bed).

METHODS AND MATERIALS

Thirty one patients who had planned for radiotherapy after radical prostatectomy were enrolled and underwent computed tomography and magnetic resonance imaging (MRI) simulation prior to radiotherapy. Through an iterative process of consultation and discussion, an interdisciplinary consensus definition was derived based on a review of published data, patterns of local failure, surgical practice, and radiologic anatomy. In validation, we analyzed the distribution of surgical clips in reference to the consensus CTV and measured spatial uncertainties in delineating the CTV and vesicourethral anastomosis. Clinical radiotherapy plans were retrospectively evaluated against the consensus CTV (prostate bed).

RESULTS

Anatomic boundaries of the consensus CTV (prostate bed) are described. Surgical clips (n = 339) were well distributed throughout the CTV. The vesicourethral anastomosis was accurately localized using central sagittal computed tomography reconstruction, with a mean +/- standard deviation uncertainty of 1.8 +/- 2.5 mm. Delineation uncertainties were small for both MRI and computed tomography (mean reproducibility, 0-3.8 mm; standard deviation, 1.0-2.3); they were most pronounced in the anteroposterior and superoinferior dimensions and at the superior/posterior-most aspect of the CTV. Retrospectively, the mean +/- standard deviation CTV (prostate bed) percentage of volume receiving 100% of prescribed dose was only 77% +/- 26%.

CONCLUSIONS

We propose anatomic boundaries for the CTV (prostate bed) and present evidence supporting its validity. In the absence of gross recurrence, the role of MRI in delineating the CTV remains to be confirmed. The CTV is larger than historically practiced at our institution and should be encompassed by a microscopic tumoricidal dose.

Phase II Trial of Hypofractionated Image-Guided Intensity-Modulated Radiotherapy for Localized Prostate Adenocarcinoma

PURPOSE

To assess in a prospective trial the feasibility and late toxicity of hypofractionated radiotherapy (RT) for prostate cancer.

METHODS AND MATERIALS

Eligible patients had clinical stage T1c-2cNXM0 disease. They received 60 Gy in 20 fractions over 4 weeks with intensity-modulated radiotherapy including daily on-line image guidance with intraprostatic fiducial markers.

RESULTS

Between June 2001 and March 2004, 92 patients were treated with hypofractionated RT. The cohort had a median prostate-specific antigen value of 7.06 ng/mL. The majority had Gleason grade 5-6 (38%) or 7 (59%) disease, and 82 patients had T1c-T2a clinical staging. Overall, 29 patients had low-risk, 56 intermediate-risk, and 7 high-risk disease. Severe acute toxicity (Grade 3-4) was rare, occurring in only 1 patient. Median follow-up was 38 months. According to the Phoenix definition for biochemical failure, the rate of biochemical control at 14 months was 97%. According to the previous American Society for Therapeutic Radiology and Oncology definition, biochemical control at 3 years was 76%. The incidence of late toxicity was low, with no severe (Grade > or =3) toxicity at the most recent assessment.

CONCLUSIONS

Hypofractionated RT using 60 Gy in 20 fractions over 4 weeks with image guidance is feasible and is associated with low rates of late bladder and rectal toxicity. At early follow-up, biochemical outcome is comparable to that reported for conventionally fractionated controls. The findings are being tested in an ongoing, multicenter, Phase III trial.

Patient selection determines the prostate cancer yield of dynamic contrast-enhanced magnetic resonance imaging-guided transrectal biopsies in a closed 3-Tesla scanner

OBJECTIVE

To evaluate the cancer yield of transrectal prostate biopsies in a 3-T magnetic resonance imaging (MRI) scanner in patients with elevated prostate specific antigen (PSA) levels and recent negative transrectal ultrasonography (TRUS)-guided prostate biopsies.

PATIENTS AND METHODS

Between July 2004 and November 2005, patients with at least one previous negative prostate biopsy within the previous 12 months had MRI-guided biopsy of the prostate in a 3-T MRI scanner. Patients with previous positive biopsies for cancer were excluded. Target selection was based on T2-weighted imaging and dynamic contrast-enhanced (DCE) imaging studies.

RESULTS

Thirteen patients were eligible; their median (range) age was 61 (47-74) years and PSA value 4.90 (1.3-12.3) ng/mL. Most patients had one previous negative biopsy (range 1-4). Four patients had a family history of prostate cancer. There were 37 distinct targets based on T2-weighted imaging. Fifteen of 16 distinct DCE abnormalities were co-localized with a target based on T2-weighted imaging. Despite this correlation, only one of 13 patients had a directed biopsy positive for cancer. Including systematic biopsies, two of 13 patients had a biopsy positive for prostate cancer. One patient had prostate intraepithelial neoplasia and one had atypical glands in the specimen.

CONCLUSION

The prostate-cancer yield of transrectal biopsies in a 3-T MRI scanner, among patients with recent negative TRUS-guided prostate biopsies, is similar to repeat systematic TRUS-guided biopsy. DCE correlates with T2-imaging but does not appear to improve prostate cancer yield in this population.

Dynamic contrast-enhanced magnetic resonance imaging for localization of recurrent prostate cancer after external beam radiotherapy

PURPOSE

To compare the performance of T2-weighted (T2w) imaging and dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) of the prostate gland in the localization of recurrent prostate cancer in patients with biochemical failure after external beam radiotherapy (EBRT).

METHODS AND MATERIALS

T2-weighted imaging and DCE MRI were performed in 33 patients with suspected relapse after EBRT. Dynamic contrast-enhanced MRI was performed with a temporal resolution of 95 s. Voxels enhancing at 46 s after injection to a greater degree than the mean signal intensity of the prostate at 618 s were considered malignant. Results from MRI were correlated with biopsies from six regions in the peripheral zone (PZ) (base, mid, and apex). The percentage of biopsy core positive for malignancy from each region was correlated with the maximum diameter of the tumor on DCE MRI with a linear regression model.

RESULTS

On a sextant basis, DCE MRI had significantly better sensitivity (72% [21of 29] vs. 38% [11 of 29]), positive predictive value (46% [21 of 46] vs. 24% [11 of 45]) and negative predictive value (95% [144 of 152] vs. 88% [135 of 153] than T2w imaging. Specificities were high for both DCE MRI and T2w imaging (85% [144 of 169] vs. 80% [135 of 169]). There was a linear relationship between tumor diameters on DCE MRI and the percentage of cancer tissue in the corresponding biopsy core (r = 0.9, p < 0.001), with a slope of 1.2.

CONCLUSIONS

Dynamic contrast-enhanced MRI performs better than T2w imaging in the detection and localization of prostate cancer in the peripheral zone after EBRT. This may be helpful in the planning of salvage therapy.

Role of fractionated external beam radiotherapy in hemangioblastoma of the central nervous system

PURPOSE

To assess the clinical outcomes and toxicity in patients receiving fractionated external beam radiotherapy (EBRT) for hemangioblastoma of the central nervous system, treated at two Canadian radiation oncology institutions.

METHODS AND MATERIALS

Between January 1980 and December 2004, the data of all patients receiving EBRT for central nervous system hemangioblastoma were retrospectively reviewed. The patient, tumor, and treatment characteristics were collected and overall survival, disease-free survival, and EBRT-related toxicities assessed.

RESULTS

A total of 18 cases, 5 associated with von Hippel-Lindau disease (VHL) and 13 sporadic (non-VHL), with a total 31 lesions, were documented. These were located in the cerebellum in 20 and spinal cord in 8 patients. EBRT was delivered for recurrence in 12, adjuvantly for residual disease in 4, and definitively in 2. The EBRT schedules ranged from 50.0 to 55.8 Gy in 1.8-2.0-Gy daily fractions (n = 17), typically with parallel-opposed fields to the cerebellar target volumes and direct posterior fields for spinal disease. At a median follow-up of 5.1 years (range, 0.1-14.5), the 5-year OS rate was 69% (95% confidence interval [CI], 50-96%), decreasing to 30% (95% CI, 10-87%) at 10 years. The disease-free survival rate at 5 and 10 years was 57% (95% CI, 37-87%) and 30% (95% CI, 11-83%), respectively. The outcomes differed according to VHL status. The 5-year OS rate was 100% for those with VHL compared with 55% (95% CI, 32-95%) for those with non-VHL disease (log-rank p = 0.003), and the 5-year disease-free survival rate was 80% (95% CI, 52-100%) with VHL compared with 48% (95% CI, 26-89%) without (log-rank p = 0.036).

CONCLUSIONS

Fractionated EBRT has a role in the management of extensive intracranial and/or spinal cord disease, the adjuvant treatment of residual postoperative disease, and the treatment of recurrence. More favorable outcomes were reported for VHL-associated lesions than for sporadic cases.

Intrarectal amifostine during external beam radiation therapy for prostate cancer produces significant improvements in Quality of Life measured by EPIC score

PURPOSE

To test whether intrarectal amifostine limits symptoms of radiation proctitis, measured by using the Radiation Therapy Oncology Group (RTOG) gastrointestinal (GI) toxicity score and the Expanded Prostate Cancer Index Composite (EPIC) score.

METHODS AND MATERIALS

Patients with localized prostate cancer received amifostine as a rectal suspension 30-45 minutes before daily three-dimensional conformal radiation therapy. The first 18 patients received 1 g of amifostine, and the next 12 patients received 2 g. Toxicity was assessed at baseline, during treatment, and at follow-up visits by using RTOG grading and the EPIC Quality of Life (QoL) 50-item questionnaire. The Bowel Function subset of the bowel domain (EPIC-BF), which targets symptom severity, and the Bowel Bother subset of the bowel domain (EPIC-BB), which assesses QoL, were evaluated and compared with the RTOG GI toxicity score.

RESULTS

Median follow-up was 30 months (range, 18-36 months). Overall, EPIC-BF and EPIC-BB scores both tracked closely with the RTOG GI toxicity score. Seven weeks after the start of radiation therapy, the incidence of RTOG Grade 2 toxicity was 33% in the 1-g group (6/18 patients) compared with 0% (0/12 patients) in the 2-g group and tended toward statistical significance (p = 0.06). A significant difference between amifostine groups was observed using the EPIC-BF score at 7 weeks (p = 0.04). A difference in EPIC-BB scores between dose groups was evident at 7 weeks (p = 0.07) and was significant at 12 months (p = 0.04).

CONCLUSIONS

Higher doses of amifostine produced significant improvements in acute and late bowel QoL (up to 1 year after therapy), measured using the EPIC score.

Development of Multiorgan Finite Element-Based Prostate Deformation Model Enabling Registration of Endorectal Coil Magnetic Resonance Imaging for Radiotherapy Planning

PURPOSE

Endorectal coil (ERC) magnetic resonance imaging (MRI) provides superior visualization of the prostate compared with computed tomography at the expense of deformation. This study aimed to develop a multiorgan finite element deformable method, Morfeus, to accurately co-register these images for radiotherapy planning.

METHODS

Patients with prostate cancer underwent fiducial marker implantation and computed tomography simulation for radiotherapy planning. A series of axial MRI scans were acquired with and without an ERC. The prostate, bladder, rectum, and pubic bones were manually segmented and assigned linear elastic material properties. Morfeus mapped the surface of the bladder and rectum between two imaged states, calculating the deformation of the prostate through biomechanical properties. The accuracy of deformation was measured as fiducial marker error and residual surface deformation between the inferred and actual prostate. The deformation map was inverted to deform from 100 cm(3) to no coil.

RESULTS

The data from 19 patients were analyzed. Significant prostate deformation occurred with the ERC (mean intrapatient range, 0.88 +/- 0.25 cm). The mean vector error in fiducial marker position (n = 57) was 0.22 +/- 0.09 cm, and the mean vector residual surface deformation (n = 19) was 0.15 +/- 0.06 cm for deformation from no coil to 100-cm(3) ERC, with an image vector resolution of 0.22 cm. Accurately deformed MRI scans improved soft-tissue resolution of the anatomy for radiotherapy planning.

CONCLUSIONS

This method of multiorgan deformable registration enabled accurate co-registration of ERC-MRI scans with computed tomography treatment planning images. Superior structural detail was visible on ERC-MRI, which has potential for improving target delineation.

Fractionated stereotactic radiotherapy for acoustic neuroma

BACKGROUND

The clinical outcome and toxicity of fractionated stereotactic radiotherapy (FSRT) was assessed for acoustic neuroma in 60 patients treated in a single institution.

METHODS

Between October 1996 and February 2005, 60 patients received FSRT for acoustic neuroma (AN). The mean total dose applied was 50 Gy in single daily 2-Gy fractions over 5 weeks. The median irradiated tumor volume was 4.9 cm(3) (range, 0.3-49.0 cm(3)). The median follow-up period was 31.9 months.

RESULTS

FSRT was well tolerated in all patients. The 5-year actuarial local control rate was 96.2% (95% CI: 91.1%-100.0%). Five-year actuarial progression-free survival was 92.8% (95% CI: 84.8%-100.0%). The overall hearing preservation rate was 77.3%. Five of 6 patients with initial cranial nerve V (CNV) numbness remained stable post-FSRT. Two of 3 patients with baseline trigeminal neuralgia improved with the remaining patient stable. All 3 patients with nonsurgically related facial nerve weakness either improved or achieved stability in function. There were no cases of new cranial nerve toxicity post-FSRT.

CONCLUSIONS

FSRT for the treatment of AN is safe, effective, and well tolerated. FSRT should thus be considered as an effective alternative treatment modality when compared with microsurgical resection or single fraction stereotactic radiosurgery.

Early observed transient prostate-specific antigen elevations on a pilot study of external beam radiation therapy and fractionated MRI guided high dose rate brachytherapy boost

Purpose

To report early observation of transient PSA elevations on this pilot study of external beam radiation therapy and magnetic resonance imaging (MRI) guided high dose rate (HDR) brachytherapy boost.

Materials and methods

Eleven patients with intermediate-risk and high-risk localized prostate cancer received MRI guided HDR brachytherapy (10.5 Gy each fraction) before and after a course of external beam radiotherapy (46 Gy). Two patients continued on hormones during follow-up and were censored for this analysis. Four patients discontinued hormone therapy after RT. Five patients did not receive hormones. PSA bounce is defined as a rise in PSA values with a subsequent fall below the nadir value or to below 20% of the maximum PSA level. Six previously published definitions of biochemical failure to distinguish true failure from were tested: definition 1, rise >0.2 ng/mL; definition 2, rise >0.4 ng/mL; definition 3, rise >35% of previous value; definition 4, ASTRO defined guidelines, definition 5 nadir + 2 ng/ml, and definition 6, nadir + 3 ng/ml.

Results

Median follow-up was 24 months (range 18–36 mo). During follow-up, the incidence of transient PSA elevation was: 55% for definition 1, 44% for definition 2, 55% for definition 3, 33% for definition 4, 11% for definition 5, and 11% for definition 6.

Conclusion

We observed a substantial incidence of transient elevations in PSA following combined external beam radiation and HDR brachytherapy for prostate cancer. Such elevations seem to be self-limited and should not trigger initiation of salvage therapies. No definition of failure was completely predictive.

Intrarectal amifostine suspension may protect against acute proctitis during radiation therapy for prostate cancer: a pilot study

PURPOSE

Our goal was to test the ability of intrarectal amifostine to limit symptoms of radiation proctitis.

METHODS AND MATERIALS

The first 18 patients received 1 g of intrarectal amifostine suspension placed 30-45 min before each radiation treatment. The following 12 patients received 2 g of amifostine. Total dose prescribed ranged from 66 to 76 Gy. All patients were treated with three-dimensional conformal radiation therapy. The suspension remained intrarectal during treatment and was expelled after treatment. For gastrointestinal symptoms, during treatment and follow-up, all patients had a Radiation Therapy Oncology Group (RTOG) grade recorded.

RESULTS

Median follow-up was 18 months (range, 6-24 months). With 2 g vs. 1 g amifostine, there was a nearly significant decrease in RTOG Grade 2 acute rectal toxicity. Seven weeks after the start of radiation therapy, the incidence of Grade 2 toxicity was 33% in the 1-g group (6/18) compared with 0% (0/12) in the 2-g group (p=0.06). No Grade 3 toxicity or greater occurred in this study.

CONCLUSION

This trial suggests greater rectal radioprotection from acute effects with 2 g vs. 1 g amifostine suspension. Further studies should be conducted in populations at higher risk for developing symptomatic acute and late proctitis.

Combining radiotherapy and angiogenesis inhibitors: clinical trial design

Radiotherapy (RT) plays a vital role in the multimodality treatment of cancer. Recent advances in RT have primarily involved improvements in dose delivery. Future improvements in tumor control and disease outcomes will likely involve the combination of RT with targeted therapies. Preclinical evaluations of angiogenesis inhibitors in combination with RT have yielded promising results with increased tumor "cure." It remains to be seen whether these improvements in tumor control in the laboratory will translate into improved outcomes in the clinic. Multiple differences between these agents and cytotoxic chemotherapy must be taken into account when designing clinical trials evaluating their effectiveness in combination with RT. We discuss important considerations for designing clinical trials of angiogenesis inhibitors with RT.

Discovering clinical biomarkers of ionizing radiation exposure with serum proteomic analysis

In this study, we sought to explore the merit of proteomic profiling strategies in patients with cancer before and during radiotherapy in an effort to discover clinical biomarkers of radiation exposure. Patients with a diagnosis of cancer provided informed consent for enrollment on a study permitting the collection of serum immediately before and during a course of radiation therapy. High-resolution surface-enhanced laser desorption and ionization-time of flight (SELDI-TOF) mass spectrometry (MS) was used to generate high-throughput proteomic profiles of unfractionated serum samples using an immobilized metal ion-affinity chromatography nickel-affinity chip surface. Resultant proteomic profiles were analyzed for unique biomarker signatures using supervised classification techniques. MS-based protein identification was then done on pooled sera in an effort to begin to identify specific protein fragments that are altered with radiation exposure. Sixty-eight patients with a wide range of diagnoses and radiation treatment plans provided serum samples both before and during ionizing radiation exposure. Computer-based analyses of the SELDI protein spectra could distinguish unexposed from radiation-exposed patient samples with 91% to 100% sensitivity and 97% to 100% specificity using various classifier models. The method also showed an ability to distinguish high from low dose-volume levels of exposure with a sensitivity of 83% to 100% and specificity of 91% to 100%. Using direct identity techniques of albumin-bound peptides, known to underpin the SELDI-TOF fingerprints, 23 protein fragments/peptides were uniquely detected in the radiation exposure group, including an interleukin-6 precursor protein. The composition of proteins in serum seems to change with ionizing radiation exposure. Proteomic analysis for the discovery of clinical biomarkers of radiation exposure warrants further study.

Transrectal prostate biopsy and fiducial marker placement in a standard 1.5T magnetic resonance imaging scanner

PURPOSE

We investigated the accuracy and feasibility of a system that provides transrectal needle access to the prostate concurrent with 1.5 Tesla MRI which previously has not been possible.

MATERIALS AND METHODS

In 5 patients with previously diagnosed prostate cancer, MRI guided intraprostatic placement of gold fiducial markers (4 procedures) and/or prostate biopsy (3 procedures) was performed using local anesthesia.

RESULTS

Mean procedure duration was 76 minutes and all patients tolerated the intervention well. Procedure related adverse events included self-limited hematuria and hematochezia following 3 of 8 procedures (all resolved in less than 1 week). Mean needle placement accuracy was 1.9 mm for the fiducial marker placement studies and 1.8 mm for the biopsy procedures. Mean fiducial marker placement accuracy was 4.8 mm and the mean fiducial marker placement accuracy transverse to the needle direction was 2.6 mm. All patients who underwent the procedure were able to complete their course of radiotherapy without delay or complication.

CONCLUSIONS

While studies of clinical usefulness are warranted, transrectal 1.5 T MRI guided prostate biopsy and fiducial marker placement is feasible using this system, providing new opportunities for image guided diagnostic and therapeutic prostate interventions.

Intra- and inter-radiation therapist reproducibility of daily isocenter verification using prostatic fiducial markers

Background

We sought to determine the intra- and inter-radiation therapist reproducibility of a previously established matching technique for daily verification and correction of isocenter position relative to intraprostatic fiducial markers (FM).

Materials and methods

With the patient in the treatment position, anterior-posterior and left lateral electronic images are acquired on an amorphous silicon flat panel electronic portal imaging device. After each portal image is acquired, the therapist manually translates and aligns the fiducial markers in the image to the marker contours on the digitally reconstructed radiograph. The distances between the planned and actual isocenter location is displayed. In order to determine the reproducibility of this technique, four therapists repeated and recorded this operation two separate times on 20 previously acquired portal image datasets from two patients. The data were analyzed to obtain the mean variability in the distances measured between and within observers.

Results

The mean and median intra-observer variability ranged from 0.4 to 0.7 mm and 0.3 to 0.6 mm respectively with a standard deviation of 0.4 to 1.0 mm. Inter-observer results were similar with a mean variability of 0.9 mm, a median of 0.6 mm, and a standard deviation of 0.7 mm. When using a 5 mm threshold, only 0.5% of treatments will undergo a table shift due to intra or inter-observer error, increasing to an error rate of 2.4% if this threshold were reduced to 3 mm.

Conclusion

We have found high reproducibility with a previously established method for daily verification and correction of isocenter position relative to prostatic fiducial markers using electronic portal imaging.

HPAI surveillance programme in Cambodia: results and perspectives

Cambodia has faced 15 confirmed highly pathogenic avian influenza (H5N1) outbreaks in different sectors of the poultry industry since January 2004. The country has very limited human and financial resources and, when the outbreak first began, the veterinary services were not equipped with the basic tools to collect accurate epidemiological information or to fight the disease. Therefore, different agencies, under the umbrella of the Food and Agriculture Organisation, are providing support to the Government to strengthen its capacity to diagnose, survey and control the avian influenza (AI) virus. Different surveillance tools are being tested, such as market monitoring and a sentinel villages' network, to offset the weakness of the national passive surveillance network. Several constraints were identified during the implementation of this programme, such as a lack of motivation among provincial staff, the limited capacity of the central team to compile and analyse the data generated, the reluctance of farmers to have their animals sampled, and weak diagnostic capacities. The sustainability of such a surveillance system once international support ends remains to be seen. Participatory epidemiology (PE) may be an appropriate complementary tool to track diseases. PE works on the principle that livestock keepers often possess detailed knowledge of animal diseases and can provide valuable diagnostics that could help in identifying AI outbreaks, particularly in remote areas.

MR-guided interventions for prostate cancer

MR imaging is currently the most effective diagnostic imaging tool for visualizing the anatomy and pathology of the prostate gland. Currently, the practicality and cost effectiveness of transrectal ultrasound dominates image guidance for needle-based prostate interventions. Challenges to the integration of diagnostic and interventional MR imaging have included the lack of real-time feed-back, the complexity of the imaging technique, and limited access to the perineum within the geometric constraints of the MR imaging scanner. Two basic strategies have been explored and clinically demonstrated in the literature: (1) coregistration of previously acquired diagnostic MR imaging to interventional TRUS or open scanner MR images, and (2) stereotactic needle interventions within conventional diagnostic scanners using careful patient positioning or the aid of simple manipulators. Currently, researchers are developing techniques that render MR imaging the method of choice for the direct guidance of many procedures. This article focuses on needle-based interventions for prostate cancer, including biopsy, brachytherapy, and thermal therapy With rapid progress in biologic imaging of the prostate gland, the authors believe that MR imaging guidance will play an increasing role in the diagnosis and treatment of prostate cancer.

Comparing measures of acute bowel toxicity in patients with prostate cancer treated with external beam radiation therapy

PURPOSE

This study strives to compare early measures of bowel toxicity in patients with prostate cancer receiving definitive or adjuvant 3D conformal external beam radiation therapy and concurrent daily endorectal application of amifostine.

METHODS

Eighteen patients were enrolled in the clinical study with a median follow-up of 12 months. Prescription doses ranged from 66 Gy to 76 Gy with a daily fractionation of 2 Gy. Acute bowel toxicity was measured at baseline, at Weeks 5 and 7 of radiotherapy, and at 1 and 3 months after the completion of therapy. Measures of acute bowel toxicity included the Radiation Therapy Oncology Group (RTOG) acute radiation morbidity scoring criteria, Expanded Prostate Cancer Index Composite (EPIC) self-assessment questionnaires, and proctoscopic examinations.

RESULTS

The mean EPIC bowel scores changed significantly through the course of therapy and follow-up (p < 0.0001), with a progressive decrease in scores at Weeks 5 and 7 of treatment, a partial recovery at 3 months, and a correlation to the gold standard RTOG grade (p = 0.004). Proctoscopic toxicity scores were low, did not vary over time, and did not correlate with either EPIC or RTOG scores.

CONCLUSION

The EPIC questionnaire measurements are most sensitive to changes in acute bowel toxicity through a course of radiotherapy and correlate with RTOG acute toxicity scores. Endoscopic examination of the rectal mucosa at the end and immediate follow-up of a course of therapy does not seem to be informative or reproducible between observers in the acute setting.

Combining a recombinant cancer vaccine with standard definitive radiotherapy in patients with localized prostate cancer

PURPOSE

Many patients with clinically localized prostate cancer develop biochemical failure despite excellent local therapy perhaps due to occult metastatic disease. One potential solution is the utilization of a well-tolerated systemic therapy (e.g., vaccine) in concert with local therapy.

EXPERIMENTAL DESIGN

We present a randomized phase II clinical trial designed to determine if a poxviral vaccine encoding prostate-specific antigen (PSA) can induce a PSA-specific T-cell response when combined with radiotherapy in patients with clinically localized prostate cancer. Thirty patients were randomized in a 2:1 ratio into vaccine plus radiotherapy or radiotherapy-only arms. Those patients in the combination arm received a "priming" vaccine with recombinant vaccinia (rV) PSA plus r V containing the T-cell costimulatory molecule B7.1 (rV-B7.1) followed by monthly booster vaccines with recombinant fowlpox PSA. The vaccines were given with local granulocyte-macrophage colony-stimulating factor and low-dose systemic interleukin-2. Standard external beam radiation therapy was given between the fourth and the sixth vaccinations.

RESULTS

Seventeen of 19 patients in the combination arm completed all eight vaccinations and 13 of these 17 patients had increases in PSA-specific T cells of at least 3-fold versus no detectable increases in the radiotherapy-only arm (P < 0.0005). There was also evidence of de novo generation of T cells to well-described prostate-associated antigens not found in the vaccine, providing indirect evidence of immune-mediated tumor killing. The vaccine was well tolerated.

CONCLUSION

This vaccine regimen can be safely given in patients undergoing radiation therapy for localized prostate cancer, with the majority of patients generating a PSA-specific cellular immune response to vaccine.