Estimation of patient setup uncertainty using BrainLAB Exatrac X-Ray 6D system in image-guided radiotherapy.

The purpose of this study was to evaluate setup uncertainties for brain sites with ExacTrac X-Ray 6D system and to provide optimal margin guidelines. Fifteen patients with brain tumor were included in this study. Two X-ray images with ExacTrac X-Ray 6D system were used to verify patient position and tumor target localization before each treatment. The 6D fusion software first generates various sets of DRRs with position variations in both three translational and three rotational directions (six degrees of freedom) for the CT images. Setup variations (translation and rotation) after correction were recorded and corrected before treatment. The 3D deviations are expressed as mean ± standard deviation. The random error (Σ(σi)), systematic error (µi), and group systematic error (M(µi)) for the different X-ray were calculated using the definitions of van Herk.(1) Mean setup errors were calculated from X-ray images acquired after all fractions. There is moderate patient-to-patient variation in the vertical direction and small variations in systematic errors and magnitudes of random errors are smaller. The global systematic errors were measured to be less than 2.0 mm in each direction. Random component of all patients are smaller ranging from 0.1-0.3 mm small. The safety margin (SM) to the lateral, is 0.5 mm and 2.6 mm for van Herk(1) and Stroom et al.,(2) respectively, craniocaudal axis is 1.5 mm and 3.4 mm, respectively, and with respect to the antero-posterior axis, 2.3 mm and 3.9 mm. Daily X-ray imaging is essential to compare and assess the accuracy of treatment delivery to different anatomical locations.

Fractionated stereotactic radiosurgery for patients with brain metastases.

Stereotactic radiosurgery (SRS) delivered in 2-5 fractions (multi-fraction SRS) has been employed in patients with brain metastases as an alternative to single-fraction SRS with the aim to reduce late radiation-induced toxicity while maintaining high local control rate. In the present study we have evaluated the efficacy and toxicity of multi-fraction SRS in patients with 1-3 brain metastases. Between March 2006 and October 2012, 135 patients (63 men and 72 women) with 171 brain metastases have been treated with multi-fraction SRS (3 × 9 Gy or 3 × 12 Gy). At a median follow-up of 11.4 months, 16 lesions recurred locally. The 1- and 2-year local control rates were 88 and 72 %, respectively. The 1- and 2-year survival rates were 57 and 25 %, and respective distant failure rates were 52 and 73 %. Seventy-eight percent of patients succumbed to their extracranial disease and 22 % died of progressive intracranial disease. Multivariate analysis showed that melanoma histology was predictive of local failure (p = 0.02; HR 6.1, 95 % CI 1.5-24). Specifically, the 1-year local control rates were 68 % for melanoma, 92 % for breast carcinoma, and 88 % for NSCLC, respectively. Stable extracranial disease (p = 0.004) and Karnofsky performance status (p = 0.01) were predictive of longer survival. Radiologic changes suggestive of radionecrosis occurred in 12 (7 %) out of 171 lesions, with an actuarial risk of 9 % at 1 year and 17 % at 2 years, respectively. In conclusion, multi-fraction SRS appears to be an effective and safe treatment modality for brain metastases. It may represent an alternative to single-dose SRS for patients with large lesions or lesions located near critical structures.

Factors Predicting Pathological Response to Neoadjuvant Chemoradiotherapy in Rectal Cancer: The Experience of a Single Institution with 269 Patients (STONE-01).

AIMS: The aim of this study was to define a potential benefit of pathological complete response rate (pCR) and downstaging rate after neoadjuvant chemoradiotherapy (CRT) in relation to treatment and patient factors in locally advanced rectal cancer. METHODS: We performed a retrospective cohort study. Patients were divided according to chemotherapy regimens concurrent to radiotherapy (1-drug vs. 2-drug) and according to the time interval between the end of CRT and surgery (≤8 weeks vs. >8 weeks), as well as in relation to specific relevant clinical factors. Logistic regression was used to estimate the independent factors for pCR and downstaging. RESULTS: 269 patients were eligible for this study. Overall, pCR and downstaging rates were 26% and 75.4%, respectively. Univariate analysis showed that female gender (p = 0.01) and time to surgery >8 weeks (p = 0.04) were associated with pCR; age > 70 years (p = 0.05) and time to surgery >8 weeks (p = 0.002) were correlated to downstaging. At multivariate analysis, interval time to surgery of >8 weeks was the only independent factor for both pCR and downstaging (p = 0.02; OR: 0.5, CI: 0.27-0.93 and p = 0.003; OR: 0.42, CI: 0.24-0.75, respectively). CONCLUSIONS: This study indicates that, in our population, an interval time to surgery of >8 weeks is an independent significant factor for pCR and downstaging. Further prospective studies are needed to define the best interval time.

Combining Abiraterone and Radiotherapy in Prostate Cancer Patients Who Progressed During Abiraterone Therapy.

BACKGROUND/AIM: This multicenter, retrospective, 'field-practice' study investigated treatment outcomes of ongoing abiraterone therapy with the addition of radiotherapy (RT) - initiated for oligoprogression or with a palliative intent. PATIENTS AND METHODS: Consecutive patients affected by metastatic castration-resistant prostate cancer (mCRPC) treated with abiraterone acetate were considered if they had received RT after the initiation of abiraterone treatment. RESULTS: A total of 32 patients were enrolled in the study. Median duration of abiraterone treatment was 13.0 months (range=3.8-40.9 months). Median duration of abiraterone treatment before RT was 5.9 months (range=0.4-40.0 months), and 7.2 months after RT (range=0.1-29.7 months). Median progression-free survival (PFS) was 12.6 months (95%CI=10.5-14.7) from the initiation of abiraterone treatment. From RT administration, PFS was 9.6 months (95%CI=6.4-12.9). Median overall survival (OS) since abiraterone initiation was 18.9 months (95%CI=4.7-33.0). CONCLUSION: RT prolongs abiraterone treatment in mCRPC patients leading to better clinical outcomes with this molecule.

¹8F-choline positron emission tomography/computed tomography-driven high-dose salvage radiation therapy in patients with biochemical progression after radical prostatectomy: feasibility study in 60 patients.

PURPOSE: To retrospectively review data of a cohort of patients with biochemical progression after radical prostatectomy, treated according to a uniform institutional treatment policy, to evaluate toxicity and feasibility of high-dose salvage radiation therapy (80 Gy). METHODS AND MATERIALS: Data on 60 patients with biochemical progression after radical prostatectomy between January 2009 and September 2011 were reviewed. The median value of prostate-specific antigen before radiation therapy was 0.9 ng/mL. All patients at time of diagnosis of biochemical recurrence underwent dynamic (18)F-choline positron emission tomography/computed tomography (PET/CT), which revealed in all cases a local recurrence. High-dose salvage radiation therapy was delivered up to total dose of 80 Gy to 18F-choline PET/CT-positive area. Toxicity was recorded according to the Common Terminology Criteria for Adverse Events, version 3.0, scale. RESULTS: Treatment was generally well tolerated: 54 patients (90%) completed salvage radiation therapy without any interruption. Gastrointestinal grade ≥2 acute toxicity was recorded in 6 patients (10%), whereas no patient experienced a grade ≥2 genitourinary toxicity. No grade 4 acute toxicity events were recorded. Only 1 patient (1.7%) experienced a grade 2 gastrointestinal late toxicity. With a mean follow-up of 31.2 months, 46 of 60 patients (76.6%) were free of recurrence. The 3-year biochemical progression-free survival rate was 72.5%. CONCLUSIONS: At early follow-up, (18)F-choline PET/CT-driven high-dose salvage radiation therapy seems to be feasible and well tolerated, with a low rate of toxicity.

The role of mammography after breast-conserving surgery and adjuvant chemotherapy.

AIMS AND BACKGROUND: To investigate the impact of postchemotherapy mammography on radiotherapy timing and detection of early locoregional recurrences in breast cancer patients treated with breast-conserving surgery and adjuvant chemotherapy. METHODS: Bilateral mammography was performed before radiotherapy. Mammogram assessments were collected using the Breast Imaging Reporting and Data System (BI-RADS) scale. Differences in waiting times for radiotherapy between patients who needed further evaluation after mammograms and who did not were tested by the nonparametric Mann-Whitney U test. RESULTS: A total of 277 patients who underwent locoregional restaging after conservative surgery and adjuvant chemotherapy were evaluated. All patients had surgical margins greater than 2 mm. No locoregional recurrences were detected. Only in 2 patients (0.7%) did preradiotherapy mammograms reveal a contralateral breast cancer, which was histologically confirmed. After chemotherapy, the waiting times for radiotherapy were not different between patients who needed further imaging evaluation and patients who did not (34 days, 95% CI: 29-65 vs 38 days, 95% CI: 32-39; P = NS). CONCLUSION: According to these data, postchemotherapy mammography detected a contralateral breast cancer in very few cases (0.7%); thus, even if performing these exams did not delay the start of radiotherapy, we believe that preradiotherapy mammograms are not necessary for patients undergoing adjuvant chemotherapy after breast-conserving surgery.