Conformal radiotherapy of clinically localized prostate cancer: analysis of rectal and urinary toxicity and correlation with dose-volume parameters.

AIMS AND BACKGROUND: Rectal and urinary toxicities are the principal limiting factors in delivering a high target dose to patients affected by prostate cancer. The verification of such toxicity is an important step before starting a dose-escalation program. The present observational study reports on the acute and late rectal and urinary toxicity in relation with dose-volume parameters in 104 patients with localized prostate cancer treated with 3-dimensional conformal radiation therapy. METHODS AND STUDY DESIGN: One hundred and four patients with stage T1b-T3b prostate cancer were treated with three-dimensional conformal radiation therapy to a total dose of 74 Gy, 2 Gy per fraction. Rigid dose constraints were applied for rectum and bladder. Acute and late rectal and urinary toxicities were analyzed also in relation to dose-volume histograms. Biochemical relapse-free survival was defined according to the American Society of Therapeutic Radiation Oncology (ASTRO) criteria and to the RTOG-ASTRO Phoenix Consensus Conference Recommendations using the Kaplan-Meier method. RESULTS: No grade 3 toxicity was observed. Acute and late grade 2 toxicity rates were 5.8% and 9.0% for rectum and 12.5% and 2.0% for bladder, respectively. Rectal V70 influenced the occurrence of late grade 2 toxicity. A relationship between acute and late urinary toxicity was also found. After a median follow-up of 30 months (range, 20-50), the actuarial overall and biochemical relapse-free survival rates were 84% and 77%, respectively, with a significant difference between low-intermediate and high-risk patients. CONCLUSIONS: Conformal radiotherapy to the dose of 74 Gy was administered with good compliance. The incidence of acute and late toxicity was relatively low in accord with our dose constraints. Rectal V70 proved to be a reliable prognosticator of late toxicity. Overall survival and biochemical relapse-free survival rates were more favorable for low and intermediate-risk and significantly less favorable for high-risk patients.

Patterns of practice in the radiation therapy management of rectal cancer: survey of the Interregional Group Piedmont, Valle d'Aosta and Liguria of the "Associazione Italiana di Radioterapia Oncologica (AIRO)".

AIMS AND BACKGROUND: To report the survey about the main aspects on the use of radiotherapy for the treatment of rectal cancer in Piedmont and Liguria. METHODS AND STUDY DESIGN: Sixteen centers (11 from Piedmont and 5 from Liguria) received and answered by email a questionnaire data base about clinical and technical aspects of the treatment of rectal cancer. All data were incorporated in a single data base and analyzed. RESULTS: Data regarding 593 patients who received radiotherapy for rectal cancer during the year 2009 were collected and analyzed. Staging consisted in colonoscopy, thoracic and abdominal CT, pelvic MRI and endoscopic ultrasound. PET/CT was employed to complete staging and in the treatment planning in 12/16 centers (75%). Neoadjuvant radiotherapy was employed more frequently than adjuvant radiotherapy (50% vs 36.4%), using typically a total dose of 45 Gy with 1.8 Gy/fraction. Concurrent chemoradiation with 5-fluorouracil or capecitabine was mainly employed in neoadjuvant and adjuvant settings, whereas oxaliplatin alone or in combination with 5-FU or capecitabine and leucovorin was commonly employed as the adjuvant agent. The median interval from neoadjuvant treatment to surgery was 7 weeks after long-course radiotherapy and 8 days after short-course radiotherapy. The pelvic total dose of 45 Gy in the adjuvant setting was the same in all the centers. Doses higher than 45 Gy were employed with a radical intent or in case of positive surgical margins. Hypofractionated regimens (2.5, 3 Gy to a total dose of 35-30 Gy) were used in the palliative setting. No relevant differences were observed in target volume definition and patient setup. Twenty-six patients (4.4%) developed grade 3 acute toxicity. Follow-up was scheduled in a similar way in all the centers. CONCLUSIONS: No relevant differences were found among the centers involved in the survey. The approach can help clinicians to address important clinical questions and to improve consistency and homogeneity of treatments.

Intraoperative radiotherapy during radical prostatectomy for locally advanced prostate cancer: technical and dosimetric aspects.

PURPOSE: To analyze the feasibility of intraoperative radiotherapy (IORT) in patients with high-risk prostate cancer and candidates for radical prostatectomy. METHODS AND MATERIALS: A total of 38 patients with locally advanced prostate cancer were enrolled. No patients had evidence of lymph node or distant metastases, probability of organ-confined disease >25%, or risk of lymph node involvement >15% according to the Memorial Sloan-Kettering Cancer Center Nomogram. The IORT was delivered after exposure of the prostate by a dedicated linear accelerator with beveled collimators using electrons of 9 to 12 MeV to a total dose of 10-12 Gy. Rectal dose was measured in vivo by radiochromic films placed on a rectal probe. Adminstration of IORT was followed by completion of radical prostatectomy and regional lymph node dissection. All cases with extracapsular extension and/or positive margins were scheduled for postoperative radiotherapy. Patients with pT3 to pT4 disease or positive nodes received adjuvant hormonal therapy. RESULTS: Mean dose detected by radiochromic films was 3.9 Gy (range, 0.4-8.9 Gy) to the anterior rectal wall. The IORT procedure lasted 31 min on average (range, 15-45 min). No major intra- or postoperative complications occurred. Minor complications were observed in 10/33 (30%) of cases. Of the 27/31 patients who completed the postoperative external beam radiotherapy, 3/27 experienced Grade 2 rectal toxicity and 1/27 experienced Grade 2 urinary toxicity. CONCLUSIONS: Use of IORT during radical prostatectomy is feasible and allows safe delivery of postoperative external beam radiotherapy to the tumor bed without relevant acute rectal toxicity.

Reproducibility of patient setup by surface image registration system in conformal radiotherapy of prostate cancer.

BACKGROUND: The reproducibility of patient setup for radiotherapy is based on various methods including external markers, X-rays with planar or computerized image acquisition, and, more recently, surface matching imaging. We analyzed the setup reproducibility of 16 patients affected by prostate cancer who underwent conformal radiotherapy with curative intent by using a surface image registration system. METHODS: We analyzed the setup reproducibility of 16 patients affected by prostate cancer candidates for conformal radiotherapy by using a surface image registration system. At the initial setup, EPID images were compared with DRRs and a reference 3D surface image was obtained by the AlignRT system (Vision RT, London, UK). Surface images were acquired prior to every subsequent setup procedure. EPID acquisition was repeated when errors > 5 mm were reported. RESULTS: The mean random and systematic errors were 1.2 +/- 2.3 mm and 0.3 +/- 3.0 mm along the X axis, 0.0 +/- 1.4 mm and 0.5 +/- 2.0 mm along the Y axis, and 2.0 +/- 1.8 mm and -0.7 +/- 2.4 mm along the Z axis respectively. The positioning error detected by AlignRT along the 3 axes X, Y, and Z exceeded the value of 5 mm in 14.1%, 2.0%, and 5.1% measurements and the value of 3 mm in 36.9%, 13.6% and 27.8% measurements, respectively. Correlation factors calculated by linear regression between the errors measured by AlignRT and EPID ranged from 0.77 to 0.92 with a mean of 0.85 and SD of 0.13. The setup measurements by surface imaging are highly reproducible and correlate with the setup errors detected by EPID. CONCLUSION: Surface image registration system appears to be a simple, fast, non-invasive, and reproducible method to analyze the set-up alignment in 3DCRT of prostate cancer patients.

Potential advantage of studying the lymphatic drainage by sentinel node technique and SPECT-CT image fusion for pelvic irradiation of prostate cancer.

PURPOSE: This study aims to investigate the in vivo drainage of lymphatic spread by using the sentinel node (SN) technique and single-photon emission computed tomography (SPECT)-computed tomography (CT) image fusion, and to analyze the impact of such information on conformal pelvic irradiation. METHODS AND MATERIALS: Twenty-three prostate cancer patients, candidates for radical prostatectomy already included in a trial studying the SN technique, were enrolled. CT and SPECT images were obtained after intraprostate injection of 115 MBq of 99mTc-nanocolloid, allowing identification of SN and other pelvic lymph nodes. Target and nontarget structures, including lymph nodes identified by SPECT, were drawn on SPECT-CT fusion images. A three-dimensional conformal treatment plan was performed for each patient. RESULTS: Single-photon emission computed tomography lymph nodal uptake was detected in 20 of 23 cases (87%). The SN was inside the pelvic clinical target volume (CTV2) in 16 of 20 cases (80%) and received no less than the prescribed dose in 17 of 20 cases (85%). The most frequent locations of SN outside the CTV2 were the common iliac and presacral lymph nodes. Sixteen of the 32 other lymph nodes (50%) identified by SPECT were found outside the CTV2. Overall, the SN and other intrapelvic lymph nodes identified by SPECT were not included in the CTV2 in 5 of 20 (25%) patients. CONCLUSIONS: The study of lymphatic drainage can contribute to a better knowledge of the in vivo potential pattern of lymph node metastasis in prostate cancer and can lead to a modification of treatment volume with consequent optimization of pelvic irradiation.