In Bong Ha

Concurrent chemoradiotherapy for elderly patients with stage III non-small cell lung cancer

Purpose Combined chemoradiotherapy is standard management for locally advanced non-small cell lung cancer (LA-NSCLC), but standard treatment for elderly patients with LA-NSCLC has not been confirmed yet. We evaluated the feasibility and efficacy of concurrent chemoradiotherapy (CCRT) for elderly patients with LA-NSCLC. Materials and Methods Among patients older than 65 years with LA-NSCLC, 36 patients, who underwent CCRT were retrospectively analyzed. Chemotherapy was administered 3-5 times with 4 weeks interval during radiotherapy. Thoracic radiotherapy was delivered to the primary mass and regional lymph nodes. Total dose of 54-59.4 Gy (median, 59.4 Gy) in daily 1.8 Gy fractions and 5 fractions per week. Results Regarding the response to treatment, complete response, partial response, and no response were shown in 16.7%, 66.7%, and 13.9%, respectively. The 1- and 2-year overall survival (OS) rates were 58.2% and 31.2%, respectively, and the median survival was 15 months. The 1- and 2-year progression-free survivals (PFS) were 41.2% and 19.5%, respectively, and the median PFS was 10 months. Regarding to the toxicity developed after CCRT, pneumonitis and esophagitis with grade 3 or higher were observed in 13.9% (5 patients) and 11.1% (4 patients), respectively. Treatment-related death was not observed. Conclusion The treatment-related toxicity as esophagitis and pneumonitis were noticeably lower when was compared with the previously reported results, and the survival rate was higher than radiotherapy alone. The results indicate that CCRT is an effective in terms of survival and treatment related toxicity for elderly patients over 65 years old with LA-NSCLC.

Stereotactic Body Radiation Therapy for Low- to Intermediate-risk Prostate Adenocarcinoma.

The aim of the present study was to evaluate the efficacy and toxicity of stereotactic body radiation therapy (SBRT) for low- to intermediate-risk prostate adenocarcinoma. Thirty-nine patients were retrospectively reviewed. The SBRT was delivered using the CyberKnife with the fiducial tracking method combined with In-tempo imaging. The gross target volume, which included the prostate only, was delineated on the fused CT/MRI scans. The prescription dose was delivered every other day as 5 fractions of 7.5 Gy. Venous blood was obtained before and after SBRT to assess the prostate-specific antigen (PSA) level. Toxicity was evaluated using the CTCAE, v4.03. The median follow-up time was 30.0 months. The median initial PSA level was 7.7 ng/mL. PSA levels decreased in all patients treated with SBRT, and after 5 months, the median PSA was less than 2 ng/mL. The rate of overall 3-yr actuarial biochemical failure free survival was 93.9%. Acute side effects were generally comparable with those of previous studies. The PSA change and toxicity after SBRT for low- to intermediate-risk prostate adenocarcinoma indicates favorable biochemical responses and tolerable levels of toxicity. Additionally short course treatment may produce cost benefit and convenience to patients.

Comparing the clinical outcomes in stereotactic body radiotherapy for lung tumors between Ray-Tracing and Monte- Carlo algorithms

Purpose The purpose of this study was to compare the clinical outcomes between the groups using Ray-Tracing (RAT) and Monte-Carlo (MC) calculation algorithms for stereotactic body radiotherapy (SBRT) of lung tumors. Materials and Methods Thirty-five patients received SBRT with CyberKnife for 47 primary or metastatic lung tumors. RAT was used for 22 targets in 12 patients, and MC for 25 targets in 23 patients. Total dose of 48 to 60 Gy was prescribed in 3 to 5 fractions on median 80% isodose line. The response rate, local control rate, and toxicities were compared between RAT and MC groups. Results The response rate was lower in the RAT group (77.3%) compared to the MC group (100%) (p = 0.008). The response rates showed an association with the mean dose to the gross tumor volume, which the doses were re-calculated with MC algorithm in both groups. However, the local control rate and toxicities did not differ between the groups. Conclusions The clinical outcome and toxicity of lung SBRT between the RAT and MC groups were similar except for the response rate when the same apparent doses were prescribed. The lower response rate in the RAT group, however, did not compromise the local control rates. As such, reducing the prescription dose for MC algorithm may be performed but done with caution.

Comparison of stereotactic body radiotherapy versus metastasectomy outcomes in patients with pulmonary metastases: SBRT vs. metastasectomy for PM

We compared the treatment outcomes of stereotactic body radiotherapy (SBRT) and metastasectomy in patients with pulmonary metastases.

Analysis of Motion-dependent Clinical Outcome of Tumor Tracking Stereotactic Body Radiotherapy for Prostate Cancer

Background To analyze clinical outcome of CyberKnife (CK) tumor-tracking stereotactic body radiotherapy (SBRT) for prostate cancer (Pca) according to the magnitude of intra-fractional prostate motion. Methods Medical records and daily treatment logs for 71 patients who received CK tumor-tracking SBRT were retrospectively analyzed. Statistical relationships between prostate motion and various outcome results, including local recurrence (LR), biochemical failure (BF), and treatment-related toxicity, were investigated in order to evaluate motion-dependent efficacy of tumor-tracking SBRT for Pca. Results In a total 71 patients, 3 (4.2%) patients with LR, 12 (16.9%) patients with BF, and 22 (31%) patients with grade-II or worse toxicities to rectal or bladder (22 to rectal, 22 to bladder and 8 patients to both) were observed in a median follow-up of 47 months. Magnitudes of intra-fractional tumor motion along superior-inferior, right-left, and anterior-posterior (AP) axes were 0.15 ± 0.31, 0.12 ± 0.19, and 0.73 ± 0.32 mm, respectively. Radial magnitude was estimated to be 1.0 ± 0.35 mm. Intra-fractional movement was not significantly correlated with tumor control. However, it was significant correlated with the incidence of grade-II or worse toxicity to rectum or bladder particularly when tumor motion was in the AP axis. Conclusion Our quantitative results revealed that toxicity related to SBRT treatment was highly sensitive to intra-fractional prostate movements, although local-tumor control was not affected by such movements. Our results demonstrate that precise motion correction is essential in prostate SBRT, even if it seems to be small.

Who Really Benefits from 3D-Based Planning of Brachytherapy for Cervical Cancer?

Background Although intracavitary radiotherapy (ICR) is essential for the radiation therapy of cervical cancer, few institutions in Korea perform 3-dimensional (3D)-based ICR. To identify patients who would benefit from 3D-based ICR, dosimetric parameters for tumor targets and organs at risk (OARs) were compared between 2-dimensional (2D)- and 3D-based ICR. Methods Twenty patients with locally advanced cervical cancer who underwent external beam radiation therapy (EBRT) following 3D-based ICR were retrospectively evaluated. New 2D-based plans based on the Manchester system were developed. Tumor size was measured by magnetic resonance imaging. Results The mean high risk clinical target volume (HR-CTV) D90 value was about 10% lower for 2D- than for 3D-based plans (88.4% vs. 97.7%; P = 0.068). Tumor coverage did not differ between 2D- and 3D-based plans in patients with tumors ≤ 4 cm at the time of brachytherapy, but the mean HR-CTV D90 values in patients with tumors > 4 cm were significantly higher for 3D-based plans than for 2D-based plans (96.0% vs. 78.1%; P = 0.017). Similar results were found for patients with tumors > 5 cm initially. Other dosimetric parameters for OARs were similar between 2D- and 3D-based plans, except that mean sigmoid D2cc was higher for 2D- than for 3D-based plans (67.5% vs. 58.8%; P = 0.043). Conclusion These findings indicate that 3D-based ICR plans improve tumor coverage while satisfying the dose constraints for OARs. 3D-based ICR should be considered in patients with tumors > 4 cm size at the time of brachytherapy or > 5 cm initially.

Defining the Optimal Time of Adaptive Replanning in Prostate Cancer Patients with Weight Change during Volumetric Arc Radiotherapy: A Dosimetric and Mathematical Analysis Using the Gamma Index

We evaluated the changes in the dose distribution of radiation during volumetric arc radiotherapy (VMAT), to determine the right time for adaptive replanning in prostate cancer patients with progressive weight (WT) changes. Five prostate cancer patients treated with VMAT were selected for dosimetric analysis. On the original computed tomography images, nine artificial body contours were created to reflect progressive WT changes. Combined with three different photon energies (6, 10, and 15-MV), 27 comparable virtual VMAT plans were created per patient. The dosimetric analysis included evaluation of target coverage (D95%, Dmax), conformity index, homogeneity index, and organs at risk doses. The dose differences among the plans were determined using the gamma index analysis and were compared with the dosimetric analysis. Mean D95% became lower than 98% when body contour expanded by 2.0 cm or more and Dmax became higher than 107% when body contour contracted by 1.5 cm or more in 10-MV plans. This cut-off values correlated well with gamma index analysis results. Adaptive replanning should, therefore, be considered if the depth of body contour becomes 1.5 cm smaller (WT loss) or 2.0 cm larger (WT gain) in patients treated by VMAT with 10-MV photons.