A. Semba

Respiratory Gating during Stereotactic Body Radiotherapy for Lung Cancer Reduces Tumor Position Variability

Purpose We evaluated the effects of respiratory gating on treatment accuracy in lung cancer patients undergoing lung stereotactic body radiotherapy by using electronic portal imaging device (EPID) images. Materials and Methods Our study population consisted of 30 lung cancer patients treated with stereotactic body radiotherapy (48 Gy/4 fractions/4 to 9 days). Of these, 14 were treated with- (group A) and 16 without gating (group B); typically the patients whose tumors showed three-dimensional respiratory motion ≧5 mm were selected for gating. Tumor respiratory motion was estimated using four-dimensional computed tomography images acquired during treatment simulation. Tumor position variability during all treatment sessions was assessed by measuring the standard deviation (SD) and range of tumor displacement on EPID images. The two groups were compared for tumor respiratory motion and position variability using the Mann-Whitney U test. Results The median three-dimensional tumor motion during simulation was greater in group A than group B (9 mm, range 3–30 mm vs. 2 mm, range 0–4 mm; p<0.001). In groups A and B the median SD of the tumor position was 1.1 mm and 0.9 mm in the craniocaudal- (p = 0.24) and 0.7 mm and 0.6 mm in the mediolateral direction (p = 0.89), respectively. The median range of the tumor position was 4.0 mm and 3.0 mm in the craniocaudal- (p = 0.21) and 2.0 mm and 1.5 mm in the mediolateral direction (p = 0.20), respectively. Conclusions Although patients treated with respiratory gating exhibited greater respiratory tumor motion during treatment simulation, tumor position variability in the EPID images was low and comparable to patients treated without gating. This demonstrates the benefit of respiratory gating.

Prognostic impact of the level of nodal involvement: retrospective analysis of patients with advanced oral squamous cell carcinoma

We retrospectively evaluated the prognostic impact of the level of nodal involvement in patients with advanced oral squamous cell carcinoma (SCC). Between 2005 and 2010, 105 patients with clinical stage III or IV oral SCC had chemoradiotherapy preoperatively. Clinical (cN) and pathological nodal (pN) involvement was primarily at levels Ib and II. We defined nodal involvement at levels Ia and III-V as anterior and inferior extensions, respectively, and recorded such findings as extensive. With respect to pretreatment variables (age, clinical stage, clinical findings of the primary tumour, and nodal findings), univariate analysis showed that extensive cN was the only significant factor for overall survival (hazard ratio [HR], 3.27; 95% CI 1.50 to 7.13; p=0.001). Univariate analysis showed that all pN findings, including the nodal classification (invaded nodes, multiple, and contralateral) and extensive involvement were significant, and multivariate analysis confirmed that extensive pN (HR 4.71; 95% CI 1.85 to 11.97; p=0.001) and multiple pN (HR 2.59; 95% CI 1.10 to 6.09; p=0.029) were independent predictors of overall survival. Assessment based on the level of invaded neck nodes may be a better predictor of survival than the current nodal classification.

Concurrent chemoradiotherapy with S‑1 in patients with stage III‑IV oral squamous cell carcinoma: A retrospective analysis of nodal classification based on the neck node level

The aim of the present study was to retrospectively evaluate the treatment outcomes of concurrent chemoradiotherapy (CCRT) with S-1, an oral fluoropyrimidine anticancer agent, for advanced oral squamous cell carcinoma (SCC). The study population consisted of 47 patients with clinical stage III or IV oral SCC, who underwent CCRT with S-1. Pretreatment variables, including patient age, clinical stage, T classification, midline involvement of the primary tumor and nodal status, were analyzed as predictors of survival. In addition to the N classification (node-positive, multiple and contralateral), the prognostic impact of the level of nodal involvement was assessed. Nodal involvement was mainly observed at levels Ib and II; involvement at levels Ia and III-V was considered to be anterior and inferior extension, respectively, and was recorded as extensive nodal involvement (ENI). The 3-year overall survival (OS) and progression-free survival (PFS) rates were 37 and 27%, respectively. A finding of ENI was a significant factor for OS [hazard ratio (HR)=2.16; 95% confidence interval (CI): 1.03-4.55; P=0.038] and PFS (HR=2.65; 95% CI: 1.32-5.33; P=0.005); the 3-year OS and PFS rates in patients with vs. those without ENI were 23 vs. 50% and 9 vs. 43%, respectively. The other variables were not significant. Therefore, CCRT with S-1 may be an alternative treatment for advanced oral SCC; favorable outcomes are expected in patients without ENI.

Dosimetric predictors of treatment-related lymphopenia induced by palliative radiotherapy: Predictive ability of dose-volume parameters based on body surface contour

Abstract Background Radiation-related lymphopenia has been associated with poor patient outcome. Our aim was to identify predictors of lymphopenia after palliative radiotherapy, with a focus on dose-volume parameters. Patients and methods To retrospectively assess patients with various cancers who had undergone palliative radiotherapy, we delineated three organs at risk: the volume enclosed by the body surface contour (body A), the volume left after excluding air, pleural effusion, ascites, bile, urine, and intestinal content (body B), and the volume of the bone marrow (BM). We then noted the absolute volume of the three organs at risk that had received 5-30 Gy, and assessed the predictive value for post-treatment lymphopenia of grade 3 or higher (LP3+). Results Of 54 patients, 23 (43%) developed LP3+. Univariate logistic regression analysis showed that body A V5, body A V10, body B V5, body B V10, the number of fractions, and splenic irradiation were significant predictors of LP3+ (p < 0.05). By multivariate analysis, body A V5, body A V10, body B V5, body B V10, and the number of fractions retained significance (p < 0.05). BM dose-volume parameters did not predict lymphopenia. Conclusions Higher body A and body B dose-volume parameters and a larger number of fractions may be predictors of severe lymphopenia after palliative radiotherapy.

Radiation therapy for nasopharyngeal carcinoma: the predictive value of interim survival assessment

Pretreatment characteristics are suggested as predictive and/or prognostic factors for nasopharyngeal carcinoma (NPC); however, individual tumor radiosensitivities have previously not been considered. As boost planning is recommended for NPC, we performed interim assessments of magnetic resonance (MR) images for boost planning and retrospectively evaluated their predictive value for the survival of NPC patients. Radiation therapy via elective nodal irradiation (median dose: 39.6 Gy) with/without chemotherapy was used to treat 63 NPC patients. Boost irradiation (median total dose: 70 Gy) was performed based on the interim assessment. The largest lymph node (LN) was measured on MR images acquired at the time of interim assessment. The site of first failure was local in 8 (12.7%), regional in 7 (11.1%), and distant in 12 patients (19.0%). All 7 patients with regional failure harbored LNs ≥15 mm at interim assessment. We divided the 63 patients into two groups based on LN size [large (≥15 mm), n = 10 and small (<15 mm), n = 53]. Univariate analysis showed that 5-year overall survival (OS) and cause-specific survival (CSS) rates for large LNs were significantly lower than for small LNs (OS: 12.5% vs 70.5%, P < 0.001 and CSS: 25.0% vs 80.0%, P < 0.001). Multivariate analysis showed that large LNs were a significantly unfavorable factor for both OS (hazard ratio = 4.543, P = 0.002) and CSS (hazard ratio = 6.020, P = 0.001). The results suggest that LN size at interim assessment could predict survival in NPC patients.