Comparing phase- and amplitude-gated volumetric modulated arc therapy for stereotactic body radiation therapy using 3D printed lung phantom.

PURPOSE: To compare the dosimetric impact and treatment delivery efficacy of phase-gated volumetric modulated arc therapy (VMAT) vs amplitude-gated VMAT for stereotactic body radiation therapy (SBRT) for lung cancer by using realistic three-dimensional-printed phantoms. METHODS: Four patient-specific moving lung phantoms that closely simulate the heterogeneity of lung tissue and breathing patterns were fabricated with four planning computed tomography (CT) images for lung SBRT cases. The phantoms were designed to be bisected for the measurement of two-dimensional dose distributions by using EBT3 dosimetry film. The dosimetric accuracy of treatment under respiratory motion was analyzed with the gamma index (2%/1 mm) between the plan dose and film dose measured under phase- and amplitude-gated VMAT. For the validation of the direct usage of the real-time position management (RPM) data for respiratory motion, the relationship between the RPM signal and the diaphragm position was measured by four-dimensional CT. By using data recorded during the beam delivery of both phase- and amplitude-gated VMAT, the total time intervals were compared for each treatment mode. RESULTS: Film dosimetry showed a 5.2 ± 4.2% difference of gamma passing rate (2%/1 mm) on average between the phase- vs amplitude-gated VMAT [77.7% (72.7%-85.9%) for the phase mode and 82.9% (81.4%-86.2%) for the amplitude mode]. For delivery efficiency, frequent interruptions were observed during the phase-gated VMAT, which stopped the beam delivery and required a certain amount of time before resuming the beam. This abnormality in phase-gated VMAT caused a prolonged treatment delivery time of 366 s compared with 183 s for amplitude-gated VMAT. CONCLUSIONS: Considering the dosimetric accuracy and delivery efficacy between the gating methods, amplitude mode is superior to phase mode for gated VMAT treatment.

Impact of pathologic diagnosis of internal mammary lymph node metastasis in clinical N2b and N3b breast cancer patients.

PURPOSE: To analyze the prognostic role of pathologic confirmation of internal mammary lymph nodes (IMNs) for breast cancer patients who received neoadjuvant chemotherapy. METHODS: Of the patients who were treated with neoadjuvant chemotherapy, surgery, and radiation therapy between 2009 and 2013, 114 women had suspicious IMNs and FNAB was attempted. Clinical IMN metastasis was diagnosed by 18F-FDG PET/CT positivity or pathologic confirmation (N = 70). Patients were divided into the FNAB(+) or FNAB(-) IMN group. RESULTS: The pathologic confirmation rate was 57% (40 of 70 patients). Rates were 74% in US-positive, 70% in MRI-positive, and 55% in PET-positive patients. Nodal stage was cN2b (6%) or cN3b (94%). Five-year progression-free survival (PFS) was significantly worse in patients with FNAB(+) IMN metastasis than FNAB(-) IMN metastasis (61% vs. 87%, P = 0.03). FNAB(+) IMN patients showed worse distant metastasis and regional recurrence-free survival without statistical significance (69% vs. 86%, P = 0.06, and 81% vs. 96%, P = 0.06). With median follow-up of 50.5 months (13.0-97.0 months), overall survival at 5 years was 77%, and PFS was 72%. CONCLUSIONS: Patients with FNAB-proven IMN metastasis had worse treatment outcomes compared to patients with clinically diagnosed IMN metastasis in cN2b/N3b breast cancer.

Erratum to: Retrospective analysis of treatment outcome of pediatric ependymomas in Korea: analysis of Korean multi-institutional data

The name of the 14th author was incorrect in the original publication. It is correct in this erratum (Young-Shin Ra).

Retrospective analysis of treatment outcome of pediatric ependymomas in Korea: analysis of Korean multi-institutional data.

We analyzed the treatment outcomes of intracranial ependymomas in Korean children aged <18 years. Data for 96 patients were collected from five hospitals. Survival rates were calculated using the Kaplan-Meier method. Log-rank tests for univariate analyses and Cox regression model for multivariate analysis were conducted to identify prognostic factors for survival. The median age of the patients was 4 years (range, 0.3-17.9 years). The median follow-up was 55 months (range, 2-343 months). Age <3 years was an important factor for selecting adjuvant therapy after surgery. Among children aged <3 and ≥ 3 years, adjuvant radiotherapy (RT) was applied to 55 and 84 %, respectively, and adjuvant chemotherapy to 52 and 10 %, respectively. The 5 year local progression-free survival (LPFS), disease-free survival (DFS), and overall survival (OS) rates were 54, 52, and 79 %, respectively. Gross total resection was the most significant prognostic factor for all survival endpoints. Age ≥ 3 years and RT were significant prognostic factors for superior LPFS and DFS. However, the significance of age was lost in multivariate analysis for DFS. LPFS, DFS, and OS were superior in patients who started RT within 44 days after surgery (the median time) than in patients who started RT later in the patients aged ≥ 3 years. Postoperative RT was a strong prognostic factor for intracranial ependymomas. Our results suggest that early use of RT is an essential component of treatment, and should be considered in young children.

Dosimetric evaluation of respiratory gated volumetric modulated arc therapy for lung stereotactic body radiation therapy using 3D printing technology.

PURPOSE: This study aimed to evaluate the dosimetric accuracy of respiratory gated volumetric modulated arc therapy (VMAT) for lung stereotactic body radiation therapy (SBRT) under simulation conditions similar to the actual clinical situation using patient-specific lung phantoms and realistic target movements. METHODS: Six heterogeneous lung phantoms were fabricated using a 3D-printer (3DISON, ROKIT, Seoul, Korea) to be dosimetrically equivalent to actual target regions of lung SBRT cases treated via gated VMAT. They were designed to move realistically via a motion device (QUASAR, Modus Medical Devices, Canada). Using the lung phantoms and a homogeneous phantom (model 500-3315, Modus Medical Devices), film dosimetry was performed with and without respiratory gating for VMAT delivery (TrueBeam STx; Varian Medical Systems, Palo Alto, CA, USA). The measured results were analyzed with the gamma passing rates (GPRs) of 2%/1 mm criteria, by comparing with the calculated dose via the AXB and AAA algorithms of the Eclipse Treatment Planning System (version 10.0.28; Varian Medical Systems). RESULTS: GPRs were greater than the acceptance criteria 80% for all film measurements with the stationary and homogeneous phantoms in conventional QAs. Regardless of the heterogeneity of phantoms, there were no significant differences (p > 0.05) in GPRs obtained with and without target motions; the statistical significance (p = 0.031) was presented between both algorithms under the utilization of heterogeneous phantoms. CONCLUSIONS: Dosimetric verification with heterogeneous patient-specific lung phantoms could be successfully implemented as the evaluation method for gated VMAT delivery. In addition, it could be dosimetrically confirmed that the AXB algorithm improved the dose calculation accuracy under patient-specific simulations using 3D printed lung phantoms.

Heat-induced up-regulation of NAD(P)H:quinone oxidoreductase potentiates anticancer effects of beta-lapachone.

PURPOSE: The purpose of the present study was to evaluate the efficacy of mild hyperthermia to potentiate the anticancer effects of beta-lapachone (3,4-dihydro-2,2-dimethyl-2H-naphthol[1,2-b]pyran-5,6-dione) by up-regulating NAD(P)H:quinone oxidoreductase (NQO1) in cancer cells. EXPERIMENTAL DESIGN: Effects of beta-lapachone alone or in combination with mild heating on the clonogenic survival of FSaII fibrosarcoma cells of C3H mice and A549 human lung tumor cells in vitro was determined. Effects of heating on the NQO1 level in the cancer cells in vitro were assessed using Western blot analysis for NQO1 expression, biochemical determination of NQO1 activity, and immunofluorescence microscopy for NQO1 expression. Growth of FSaII tumors in the hind legs of C3H mice was determined after treating the host mice with i.p. injection of 45 mg/kg beta-lapachone followed by heating the tumors at 42 degrees C for 1 hour every other day for four times. RESULTS: Incubation of FSaII tumor cells and A549 tumor cells with beta-lapachone at 37 degrees C reduced clonogenic survival of the cells in dose-dependent and incubation time-dependent manner. NQO1 level in the cancer cells in vitro increased within 1 hour after heating at 42 degrees C for 1 hour and remained elevated for >72 hours. The clonogenic cell death caused by beta-lapachone increased in parallel with the increase in NQO1 levels in heated cells. Heating FSaII tumors in the legs of C3H mice enhanced the effect of i.p.-injected beta-lapachone in suppressing tumor growth. CONCLUSION: We observed for the first time that mild heat shock up-regulates NQO1 in tumor cells. The heat-induced up-regulation of NQO1 enhanced the anticancer effects of beta-lapachone in vitro and in vivo.

Randomized trial of postoperative adjuvant therapy in stage II and III rectal cancer to define the optimal sequence of chemotherapy and radiotherapy: a preliminary report.

PURPOSE: We conducted a prospective randomized trial to define the optimal sequence of chemotherapy and radiotherapy of postoperative adjuvant treatment in stage II and III rectal cancer. PATIENTS AND METHODS: Three hundred eight patients were enrolled onto the study. We randomly assigned 155 to arm I (early radiotherapy group) and 153 to arm II (late radiotherapy group). Treatment included eight cycles of chemotherapy at 4-week intervals and pelvic radiotherapy of 45 Gy in 25 fractions. Radiotherapy started on day 1 of the first chemotherapy cycle in arm I and on day 1 of the third chemotherapy cycle in arm II. The chemotherapy regimen consisted of fluorouracil 375 mg/m(2)/d and leucovorin 20 mg/m(2)/d. Chemotherapy was administered for 3 days per cycle in two cycles during the period of radiotherapy and for 5 days per cycle in the remaining six cycles. RESULTS: Twenty patients in arm I and 14 in arm II were not eligible. We included 274 patients in the analysis. With a median follow-up of 37 months for surviving patients, disease-free survival was significantly prolonged in arm I compared with arm II (81% v. 70% at 4 years; P =.043). Twenty-three recurrences occurred in arm I and 38 in arm II (P =.047). Overall survival was not significantly different between arms I and II (84% v. 82% at 4 years; P =.387). CONCLUSION: Early radiotherapy with concurrent chemotherapy after resection of stage II and III rectal cancer demonstrated a statistically significant advantage for disease-free survival compared with late radiotherapy with chemotherapy.

Susceptibility of cancer cells to beta-lapachone is enhanced by ionizing radiation.

PURPOSE: To reveal the interaction between beta-lapachone (beta-lap) and ionizing radiation (IR) in causing clonogenic death in cancer cells and to elucidate the potential usefulness of beta-lap treatment in combination with radiotherapy of cancer. METHODS AND MATERIALS: FSaII tumor cells of C3H mice were used. The cytotoxicity of beta-lap alone or in combination with IR in vitro was determined using clonogenic survival assay method. The IR-induced changes in the expression and the enzymatic activity of NAD(P)H:quinone oxidoreductase (NQO1), a mediator of beta-lap cytotoxicity, were elucidated and the relationship between the NQO1 level and the sensitivity of cells to beta-lap was investigated. The combined effect of IR and beta-lap to suppress tumor growth was studied using FSaII tumors grown subcutaneously in the thigh of C3H mice. RESULTS: beta-Lap caused clonogenic death of FSaII tumor cells in vitro in a dose- and time-dependent manner. When cells were treated first with beta-lap and then exposed to IR in vitro, the resultant cell death was only additive. On the contrary, exposing cells to IR at 2.5 Gy first and then treating the cells with beta-lap killed the cells in a synergistic manner. Importantly, the 2.5 Gy cells were sensitive to beta-lap as long as 10 h after irradiation, which was long after the sublethal radiation damage was repaired. Irradiation of FSaII cells in vitro with 2.5 Gy significantly increased the expression and enzymatic activity of NQO1. The growth delay of FSaII tumors caused by an intraperitoneal injection of beta-lap in combination with 20 Gy irradiation of tumor was significantly greater than that caused by beta-lap or 20 Gy irradiation alone. CONCLUSION: The sensitivity of cells to beta-lap is dependent on NQO1 activity. IR caused a long-lasting increase in NQO1 activity in cancer cells, thereby sensitizing cells to beta-lap and treatment of experimental mouse tumors with IR and beta-lap suppressed tumor growth in a synergistic manner. The combination of beta-lap and radiotherapy is a potentially effective regimen for the treatment of human cancer.

The safety and efficacy of EGF-based cream for the prevention of radiotherapy-induced skin injury: results from a multicenter observational study.

PURPOSE: This study was designed to evaluate the efficacy and safety of topically applied recombinant human epidermal growth factor (rhEGF) for the prevention of radiation-induced dermatitis in cancer patients. MATERIALS AND METHODS: From December 2010 to April 2012, a total of 1,172 cancer patients who received radiotherapy (RT) of more than 50 Gy were prospectively enrolled and treated with EGF-based cream. An acute skin reaction classified according to the Radiation Therapy Oncology Group 6-point rating scale was the primary end point and we also assessed the occurrence of edema, dry skin, or pruritus. RESULTS: The percentage of radiation dermatitis with maximum grade 0 and grade 1 was 19% and 58% at the time of 50 Gy, and it became 29% and 47% after completion of planned RT. This increment was observed only in breast cancer patients (from 18%/62% to 32%/49%). Adverse events related to the EGF-based cream developed in 49 patients (4%) with mild erythema the most common. Skin toxicity grade >2 was observed in 5% of the patients. Edema, dry skin, and pruritus grade ≥3 developed in 9%, 9%, and 1% of the patients, respectively. CONCLUSION: Prophylactic use of an EGF-based cream is effective in preventing radiation dermatitis with tolerable toxicity. Further studies comparing EGF cream with other topical agents may be necessary.

Randomized trial of postoperative adjuvant therapy in Stage II and III rectal cancer to define the optimal sequence of chemotherapy and radiotherapy: 10-year follow-up.

PURPOSE: To determine the optimal sequence of postoperative adjuvant chemotherapy and radiotherapy in patients with Stage II or III rectal cancer. METHODS AND MATERIALS: A total of 308 patients were randomized to early (n = 155) or late (n = 153) radiotherapy (RT). Treatment included eight cycles of chemotherapy, consisting of fluorouracil 375 mg/m(2)/day and leucovorin 20 mg/m(2)/day, at 4-week intervals, and pelvic radiotherapy of 45 Gy in 25 fractions. Radiotherapy started on Day 1 of the first chemotherapy cycle in the early RT arm and on Day 1 of the third chemotherapy cycle in the late RT arm. RESULTS: At a median follow-up of 121 months for surviving patients, disease-free survival (DFS) at 10 years was not statistically significantly different between the early and late RT arms (71% vs. 63%; p = 0.162). A total of 36 patients (26.7%) in the early RT arm and 49 (35.3%) in the late RT arm experienced recurrence (p = 0.151). Overall survival did not differ significantly between the two treatment groups. However, in patients who underwent abdominoperineal resection, the DFS rate at 10 years was significantly greater in the early RT arm than in the late RT arm (63% vs. 40%; p = 0.043). CONCLUSIONS: After the long-term follow-up duration, this study failed to show a statistically significant DFS advantage for early radiotherapy with concurrent chemotherapy after resection of Stage II and III rectal cancer. Our results, however, suggest that if neoadjuvant chemoradiation is not given before surgery, then early postoperative chemoradiation should be considered for patients requiring an abdominoperineal resection.