Cisplatin- vs. oxaliplatin-based radiosensitizing chemotherapy for squamous cell carcinoma of the esophagus: a comparison of two preoperative radiochemotherapy regimens.

PURPOSE: To compare the outcomes of two neoadjuvant radiochemotherapy (N-RCT) regimens for squamous cell carcinoma of the esophagus (ESCC). METHODS: The standard N-RCT regimen for ESCC at our institution between 2002 and 2011 was a total dose of 45 Gy (1.8-Gy fractions) with concomitant cisplatin (20 mg/m(2), days 1-5 and 29-33) and 5-fluorouracil (5-FU; 225 mg/m(2), 24 h continuous infusion on days 1-33). During the same period, a phase I/II study comparing the standard ESCC N-RCT protocol with a regimen identical except for the replacement of cisplatin with weekly oxaliplatin (40-50 mg/m(2)) was performed at our center. The standard regimen was used to treat 40 patients; 37 received the oxaliplatin regimen. All patients subsequently underwent radical resection with reconstruction according to tumor location and two-field lymph node dissection. RESULTS: Median follow-up time from the start of N-RCT was 74 months (range 3-116 months). The two patient groups were comparable in terms of demographic and baseline tumor characteristics. R0 resection was achieved in 37/39 patients (95 %) in the cisplatin-based N-RCT group, compared to 24/37 (65 %) in the oxaliplatin-based group (p = 0.002). A pathological complete response (pCR) was seen in the resection specimens from 18/39 patients (46 %) in the cisplatin-based N-RCT group and in 8/37 (22 %) oxaliplatin-group patients. In the cisplatin group, 2- and 5-year overall survival (OS) rates were 67 ± 8 % and 60 ± 8 %, respectively (median OS 103 months), compared to 38 ± 8 % and 32 ± 8 %, respectively, for the oxaliplatin group (median OS 17 months; hazard ratio, HR 0.452; 95 % confidence interval, CI 0.244-0.839; p = 0.012). CONCLUSION: Oxaliplatin-based N-RCT resulted in poorer outcomes in ESCC patients and should not routinely replace cisplatin-based N-RCT.

Protection of quality and innovation in radiation oncology: the prospective multicenter trial QUIRO of DEGRO: evaluation of time, attendance of medical staff, and resources during radiotherapy with tomotherapy.

PURPOSE: The technical progress in radiotherapy in recent years has been tremendous. This also implies a change of human and time resources. However, there is a lack of data on this topic. Therefore, the DEGRO initiated several studies in the QUIRO project on this subject. The present publication focuses on results for tomotherapy systems and compares them with other IMRT techniques. METHODS: Over a period of several months, time allocation was documented using a standard form at two university hospitals. The required time for individual steps in the treatment planning process was recorded for all involved professional groups (physicist, technician, and physician) by themselves. The time monitoring at the treatment machines was performed by auxiliary employees (student research assistants). Evaluation of the data was performed for all recorded data as well as by tumor site. A comparison was made between the two involved institutions. RESULTS: A total of 1,691 records were analyzed: 148 from head and neck (H&N) tumors, 460 from prostate cancer, 136 from breast cancer, and 947 from other tumor entities. The mean value of all data from both centers for the definition of the target volumes for H&N tumors took a radiation oncology specialist 75 min, while a physicist needed for the physical treatment planning 214 min. For prostate carcinomas, the times were 60 and 147 min, respectively, and for the group of other entities 63 and 192 min, respectively. For the first radiation treatment, the occupancy time of the linear accelerator room was 31, 26, and 30 min for each entity (H&N, prostate, other entities, respectively). For routine treatments 22, 18, and 21 min were needed for the particular entities. Major differences in the time required for the individual steps were observed between the two centers. CONCLUSION: This study gives an overview of the time and personnel requirements in radiation therapy using a tomotherapy system. The most representative analysis could be done for the room occupancy times during treatment in both centers. Due to the partly small amount of data and differing planning workflows between the two centers, it is problematic to draw a firm conclusion with regard to planning times. Overall, the time required for the tomotherapy treatment and planning is slightly higher compared to other IMRT techniques.

Three-dimensional imaging of whole mouse models: comparing nondestructive X-ray phase-contrast micro-CT with cryotome-based planar epi-illumination imaging.

In this study, we compare two evolving techniques for obtaining high-resolution 3D anatomical data of a mouse specimen. On the one hand, we investigate cryotome-based planar epi-illumination imaging (cryo-imaging). On the other hand, we examine X-ray phase-contrast micro-computed tomography (micro-CT) using synchrotron radiation. Cryo-imaging is a technique in which an electron multiplying charge coupled camera takes images of a cryo-frozen specimen during the sectioning process. Subsequent image alignment and virtual stacking result in volumetric data. X-ray phase-contrast imaging is based on the minute refraction of X-rays inside the specimen and features higher soft-tissue contrast than conventional, attenuation-based micro-CT. To explore the potential of both techniques for studying whole mouse disease models, one mouse specimen was imaged using both techniques. Obtained data are compared visually and quantitatively, specifically with regard to the visibility of fine anatomical details. Internal structure of the mouse specimen is visible in great detail with both techniques and the study shows in particular that soft-tissue contrast is strongly enhanced in the X-ray phase images compared to the attenuation-based images. This identifies phase-contrast micro-CT as a powerful tool for the study of small animal disease models.

Localization and quantification of the delivered dose to the spinal cord. Predicting actual delivered dose during daily MVCT image-guided tomotherapy.

PURPOSE: The goal of the present work was to localize and quantify the actual delivered dose to the cervical spinal cord (SC) during head and neck cancer (H&N) treatment. MATERIALS AND METHODS: A total of 20 H&N patients treated with bilateral nodal irradiation with helical tomotherapy (HT) were analyzed. Daily MVCTs were performed for image guidance. On every second MVCT, the SC was recontoured and the delivered dose for the given treatment fraction (12 fractions per patient) was recalculated. The magnitude and localization (CT slice, spinal cord quadrant) of the Dmax to the SC on the planning CT (PLAN-Dmax) and of the actual delivered Dmax (a-Dmax) were analyzed. RESULTS: A systematic deviation from the PLAN-Dmax was observed in 15 out of 20 patients. Large interpatient variability of the a-Dmax in the spinal cord was noted (4.5±4%). Intrapatient variability in a-Dmax was, generally, minimal (1.8±2.7%). Throughout the treatment course, the higher dose was located in the same CT slices and in the same quadrants (anterior right and anterior left) for the same patient. CONCLUSION: Exact localization and quantification of the change of the a-Dmax can be made for most patients by recalculating the dose on the daily IGRT-MVCTs. This could be helpful in assessing whether replanning is necessary in patients with doses close to the known tolerance doses of the spinal cord.

Fractionated stereotactic radiotherapy in the treatment of pituitary adenomas.

PURPOSE: The purpose of this work was to evaluate tumor control and side effects associated with fractionated stereotactic radiotherapy (FSRT) in the management of residual or recurrent pituitary adenomas. PATIENTS AND METHODS: We report on 37 consecutive patients with pituitary adenomas treated with FSRT at our department. All patients had previously undergone surgery. Twenty-nine patients had nonfunctioning, 8 had hormone-producing adenoma. The mean total dose delivered by a linear accelerator was 49.4 Gy (range 45-52.2 Gy), 5 × 1.8 Gy weekly. The mean PTV was 22.8 ccm (range 2.0-78.3 ccm). Evaluation included serial imaging tests, endocrinologic and ophthalmologic examination. RESULTS: Tumor control was 91.9 % for a median follow-up time of 57 months (range 2-111 months). Before FSRT partial hypopituitarism was present in 41 % of patients, while 35 % had anterior panhypopituitarism. After FSRT pituitary function remained normal in 22 %, 43 % had partial pituitary dysfunction, and 35 % had anterior panhypopituitarism. Visual acuity was stable in 76 % of patients, improved in 19 %, and deteriorated in 5 %. Visual fields remained stable in 35 patients (95 %), improved in one and worsened in 1 patient (2.7 %). CONCLUSION: FSRT is an effective and safe treatment for recurrent or residual pituitary adenoma. Good local tumor control and preservation of adjacent structures can be reached, even for large tumors.

Chronic adverse events and quality of life after radiochemotherapy in anal cancer patients. A single institution experience and review of the literature.

PURPOSE: To report on chronic adverse events (CAE) and quality of life (QOL) after radiochemotherapy (RCT) in patients with anal cancer (AC). PATIENTS AND METHODS: Of 83 patients who had received RCT at our department between 1988 and 2011, 51 accepted the invitation to participate in this QOL study. CAE were evaluated using the Common Terminology Criteria for Adverse Events (CTCAE) v. 4.0 and QOL was assessed with the Functional Assessment of Cancer Therapy-Colorectal (FACT-C) questionnaire. RESULTS: CAE could be evaluated in 49 patients. There was a tendency toward a higher rate of grade 3 CAE in female patients, i.e. 18 out of 37 (49 %) vs. 2 out of 12 (17 %) male patients (p = 0.089). The most common grade 3 CAE were dyspareunia and vaginal symptoms (itching, burning and dryness) in 35 and 22 % of female patients, respectively, followed by stool incontinence in 13 % of all patients (6 out of 49). Both FACT-C and CAE information were available for 42 patients, allowing evaluation of the impact of CAE on QOL. The median total FACT-C score was 110 (40-132) out of a possible maximum of 136. The absence of grade 3 CAE (115 vs. 94, p = 0.001); an interval of ≥ 67 months after the end of the treatment (111 vs. 107, p = 0.010), no stool incontinence vs. grade 3 stool incontinence (111 vs. 74, p = 0.009), higher education (114 vs. 107, p = 0.013) and no dyspareunia vs. grade 3 dyspareunia (116 vs. 93, p = 0.012) were significantly associated with a higher median FACT-C score. CONCLUSION: The majority of AC patients treated with RCT have acceptable overall QOL scores, which are comparable to those of the normal population. Patients with grade 3 CAE-particularly dyspareunia and fecal incontinence-have a poorer QOL compared to patients without CAE. In order to improve long-term QOL, future strategies might aim at a reduction in dose to the genitalia and more intensive patient support measures.

Positron-emission tomography CT to identify local recurrence in stage I lung cancer patients 1 year after stereotactic body radiation therapy.

PURPOSE: To evaluate the diagnostic value of positron-emission tomography/computed tomography (PET/CT) in stage I lung cancer patients treated with stereotactic body radiation therapy (SBRT), who have suspicious or unclear local recurrence findings in CT 1 year after treatment. PATIENTS AND METHODS: A group of 29 patients with unclear or suspicious CT findings 1 year after SBRT were examined with PET/CT. The ability of standard uptake values (SUVmax, SUVmean and posttherapeutic reduction in SUV) to detect local failure and identify patients at a high risk of disease-specific death was evaluated using logrank statistics. Histology and clinical follow-up were the gold standards for local recurrence. RESULTS: SUVmean greater than 3.44 (p = 0.001); SUVmax greater than 5.48 (p = 0.009) or a relative reduction in SUVmean or SUVmax of less than 43 (p = 0.030) or 52 % (p = 0.025), respectively, was indicative of local recurrence. These parameters also correlated with an increased risk of disease-specific death: SUVmean greater than 2.81 (p = 0.023); SUVmax greater than 3.45 (p = 0.007) or a relative reduction in SUVmean or SUVmax of less than 32 (p = 0.015) or 52 % (p = 0.013), respectively, was indicative of an increased risk of disease-specific death. CONCLUSION: PET/CT performed 1 year after SBRT can reliably identify local recurrence and therefore help to clarify unclear CT findings. As posttherapeutic glucose metabolism also correlates with disease-specific survival, PET/CT may help to stratify lung cancer patients for additional treatment 1 year after SBRT.

Advanced techniques in neoadjuvant radiotherapy allow dose escalation without increased dose to the organs at risk : Planning study in esophageal carcinoma.

PURPOSE: The goal of this work was to investigate the potential of advanced radiation techniques in dose escalation in the radiotherapy (RT) for the treatment of esophageal carcinoma. METHODS: A total of 15 locally advanced esophageal cancer (LAEC) patients were selected for the present study. For all 15 patients, we created a 3D conformal RT plan (3D-45) with 45 Gy in fractions of 1.8 Gy to the planning target volume (PTV1), which we usually use to employ in the neoadjuvant treatment of LAEC. Additionally, a 3D boost (as in the primary RT of LAEC) was calculated with 9 Gy in fractions of 1.8 Gy to the boost volume (PTV2) (Dmean) to a total dose of 54 Gy (3D-54 Gy), which we routinely use for the definitive treatment of LAEC. Three plans with a simultaneous integrated boost (SIB) were then calculated for each patient: sliding window intensity-modulated radiotherapy (IMRT-SIB), volumetric modulated arc therapy (VMAT-SIB), and helical tomotherapy (HT-SIB). For the SIB plans, the requirement was that 95 % of the PTV1 receive ≥ 100 % of the prescription dose (45 Gy in fractions of 1.8 Gy, D95) and the PTV2 was dose escalated to 52.5 Gy in fractions of 2.1 Gy (D95). RESULTS: The median PTV2 dose for 3D-45, 3D-54, HT-SIB, VMAT-SIB, and IMRT-SIB was 45, 55, 54, 56, and 55 Gy, respectively. Therefore, the dose to PTV2 in the SIB plans was comparable to the 3D-54 plan. The lung dose in the SIB plans was in the range of the standard 3D-45, which is applied for neoadjuvant radiotherapy. The mean lung dose for the same plans was 13, 15, 12, 12, and 13 Gy, respectively. The V5 lung volumes were 71, 74, 79, 75, and 73 %, respectively. The V20 lung volumes were 20, 25, 16, 18, and 19 %, respectively. CONCLUSION: New treatment planning techniques enable higher doses to be delivered for neoadjuvant radiotherapy of LAEC without a significant increase in the delivered dose to the organs at risk. Clinical investigations are warranted to study the clinical safety and feasibility of applying higher doses through advanced techniques in the neoadjuvant treatment of LAEC.

Radiotherapy with or without chemotherapy in the treatment of anal cancer: 20-year experience from a single institute.

PURPOSE: To report the efficacy and toxicity of radio(chemo)therapy (RCT) in the management of squamous cell anal carcinoma (SQ-AC) and to evaluate the prognostic factors influencing the outcomes. PATIENTS AND METHODS: A consecutive cohort of 138 patients with cT1-4, cN0-3, cM0 SQ-AC were treated with RCT between 1988 and 2011 at our department. Median follow-up time for surviving patients from the start of RCT was 98 months (range, 1-236 months). Patients were treated with a median radiation dose of 56 Gy (range, 4-61 Gy). Concurrent chemotherapy was administered to 119 patients (86%). RESULTS: The survival rates at 2, 5, and 10 years were 88 ± 3, 82 ± 4, and 59 ± 6%, respectively, with a median overall survival (OS) of 167 months. The cumulative incidence for local recurrence at 2 and 5 years was 8 ± 2 and 11 ± 3%, respectively. The median disease-free survival (DFS) and colostomy-free survival (CFS) times were 132 and 135 months, respectively. In 19 patients (14%), a distant metastasis was diagnosed after a median time of 19 months. In the multivariate analysis, UICC (International Union Against Cancer) stage I-II, female gender, Eastern Cooperative Oncology Group (ECOG) performance status of 0-1, and good/moderate histologic differentiation (G1-2) were significantly associated with a better OS, DFS, and CFS. Conformal radiotherapy planning techniques were significantly associated with a lower cumulative incidence of local recurrence (11 ± 3% vs. 38 ± 19% at 5 years, p = 0.006). A higher radiation dose beyond 54 Gy was not associated with an improvement in outcome, neither for smaller-(T1/T2) nor for larger tumors (T3/T4). CONCLUSION: RCT leads to excellent outcomes-especially in patients with stage I/II and G1/G2 tumors-with acceptable toxicity. The probable advantages of high-dose radiotherapy should be considered carefully against the risk of a higher rate of toxicity. Future studies are needed to investigate the role of a more intensified (systemic) treatment for patients with unfavorable prognostic factors such as T3/T4, N+, and/or poor cell differentiation.

Low LET protons focused to submicrometer shows enhanced radiobiological effectiveness.

This study shows that enhanced radiobiological effectiveness (RBE) values can be generated focusing low linear energy transfer (LET) radiation and thus changing the microdose distribution. 20 MeV protons (LET = 2.65 keV µm(-1)) are focused to submicrometer diameter at the ion microprobe superconducting nanoprobe for applied nuclear (Kern) physics experiments of the Munich tandem accelerator. The RBE values, as determined by measuring micronuclei (RBE(MN) = 1.48 ± 0.07) and dicentrics (RBE(D) = 1.92 ± 0.15), in human-hamster hybrid (A(L)) cells are significantly higher when 117 protons were focused to a submicrometer irradiation field within a 5.4 × 5.4 µm(2) matrix compared to quasi homogeneous in a 1 × 1 µm(2) matrix applied protons (RBE(MN) = 1.28 ± 0.07; RBE(D) = 1.41 ± 0.14) at the same average dose of 1.7 Gy. The RBE values are normalized to standard 70 kV (dicentrics) or 200 kV (micronuclei) x-ray irradiation. The 117 protons applied per point deposit the same amount of energy like a (12)C ion with 55 MeV total energy (4.48 MeV u(-1)). The enhancements are about half of that obtained for (12)C ions (RBE(MN) = 2.20 ± 0.06 and RBE(D) = 3.21 ± 0.10) and they are attributed to intertrack interactions of the induced damages. The measured RBE values show differences from predictions of the local effect model (LEM III) that is used to calculate RBE values for irradiation plans to treat tumors with high LET particles.

Respiratory gated [18F]FDG PET/CT for target volume delineation in stereotactic radiation treatment of liver metastases.

PURPOSE: The use of 4D-[(18)F]fluorodeoxyglucose (FDG) PET/CT in combination with respiratory gated magnet resonance imaging (MRI) in target volume definition for stereotactic radiation of liver metastases was investigated. METHODS AND MATERIALS: A total of 18 patients received respiration gated FDG-PET/CT and MRI. Data were fused using a rigid co-registration algorithm. The quality of the co-registration was rated on a scale from 1 (excellent) to 5 (poor) for co-registration of MRI with gated PET and ungated PET. Gross tumor volume (GTV) was delineated in CT (GTV (CT)), MRI (GTV(MRI)), and PET (GTV(PET)). MRI- and PET-based GTVs were defined by three observers each. Interobserver variability was calculated for all patients as well as for subgroups with and without previous treatment of liver metastases. All GTVs were compared for all patients and separately for patients with previous local therapy. In addition, a semiautomatic segmentation algorithm was applied on the PET images. RESULTS: Co-registration between MR and PET images was rated with 3.3 in average when non-gated PET was used and improved significantly (p < 0.01) to 2.1 using gated PET. The average GTV(CT) was 51.5 ml, GTV(MRI) 51.8 ml, and the average GTV(PET) 48.1 ml. Volumes delineated in MRI were 9.9% larger compared to those delineated in CT. Volumes delineated in PET were 13.8% larger than in MRI. The differences between the GTVs were more pronounced in patients with previous treatment. The GTVs defined in MRI showed an interobserver variability of 47.9% (84.1% with previous treatment and 26.2% without previous treatment). The PET-defined GTVs showed an interobserver variability of 21% regardless of previous treatment. Semiautomatic segmentation did not provide satisfying results. CONCLUSION: FDG-PET can distinguish vital tumor tissue and scar tissue, and therefore alters the GTV especially in patients with previous local treatment. In addition, it reduces the interobserver variability significantly compared to MRI. However, respiratory gated PET is necessary for good co-registration of PET and MRI.

Radiotherapy in stage I-III follicular non-Hodgkin lymphoma. Retrospective analysis of a series of 50 patients.

PURPOSE: The goal of this work was to analyze the response rate and outcome of patients with stage I-III follicular lymphoma (FL) treated with radiotherapy (RT) alone. PATIENTS AND METHODS: The records of 50 consecutive patients with stage I-III FL treated with RT alone at our department from 1988-2009 were analyzed. The median age was 60 years (range 32-80 years) with a median follow-up duration of 8 years (range 4-11 years). Clinical staging was performed according to the Ann Arbor system. Stage I: 30 patients (60%), stage II: 15 patients (30%), stage III: 5 patients (10%). Thirty-two patients (64%) presented with nodal disease, 14 patients (28%) presented with disease in extranodal sites, and 4 patients (8%) had nodal and extranodal involvement. The RT field encompassed only the involved Ann Arbor nodal regions (involved-field RT) in 26 patients (52%), mantle and whole abdominopelvic fields in 6 patients (12%), mantle field in 10 patients (20%), whole abdominopelvic fields in 5 patients (10%), and a so-called mini-mantle in 3 patients (6%). The total RT dose ranged from 26-56 Gy (median 40 Gy) in daily fractions of 1.2-2.5 Gy. RESULTS: Complete remission (CR) and partial remission (PR) were observed in 39 (76%) and 9 (20%) patients, respectively. Only 2 of 8 patients (25%) with tumor bulk > 5 cm reached CR, whereas 37 of 42 patients (88%) with a maximum lymphoma diameter < 5 cm achieved CR (p = 0.0001). The median overall survival (OS) and median event-free survival (EFS) were 18 years (CI 95% 10-26 years) and 7 years (6-8 years), respectively. The 2-, 5-, and 10-year OS were 96 ± 3%, 90 ± 5%, and 70 ± 9%, respectively. The 2-, 5-, and 10-year EFS were 90 ± 5%, 70 ± 7%, and 38 ± 9%, respectively. Fifteen patients developed a recurrence outside the radiation field (30%) and 4 patients developed an in-field recurrence (8%). All in-field recurrences were observed in regions without clinical (macroscopic) involvement, which were irradiated with a dose of ≤ 26 Gy. Pretreatment maximum lymphoma diameter < 5 cm (p = 0.039) and complete remission after RT (p = 0.021) were significantly associated with a better OS in the univariate analysis. CONCLUSION: RT is a curative option in the treatment of limited stage FL. If RT of microscopically uninvolved area is necessary, a reduction in the radiation dose should be carefully weighed against the risk of in-field recurrences.

Dose-escalated simultaneous integrated-boost treatment of prostate cancer patients via helical tomotherapy.

PURPOSE: The goal of this work was to assess the feasibility of moderately hypofractionated simultaneous integrated-boost intensity-modulated radiotherapy (SIB-IMRT) with helical tomotherapy in patients with localized prostate cancer regarding acute side effects and dose-volume histogram data (DVH data). METHODS: Acute side effects and DVH data were evaluated of the first 40 intermediate risk prostate cancer patients treated with a definitive daily image-guided SIB-IMRT protocol via helical tomotherapy in our department. The planning target volume including the prostate and the base of the seminal vesicles with safety margins was treated with 70 Gy in 35 fractions. The boost volume containing the prostate and 3 mm safety margins (5 mm craniocaudal) was treated as SIB to a total dose of 76 Gy (2.17 Gy per fraction). Planning constraints for the anterior rectal wall were set in order not to exceed the dose of 76 Gy prescribed to the boost volume. Acute toxicity was evaluated prospectively using a modified CTCAE (Common Terminology Criteria for Adverse Events) score. RESULTS: SIB-IMRT allowed good rectal sparing, although the full boost dose was permitted to the anterior rectal wall. Median rectum dose was 38 Gy in all patients and the median volumes receiving at least 65 Gy (V65), 70 Gy (V70), and 75 Gy (V75) were 13.5%, 9%, and 3%, respectively. No grade 4 toxicity was observed. Acute grade 3 toxicity was observed in 20% of patients involving nocturia only. Grade 2 acute intestinal and urological side effects occurred in 25% and 57.5%, respectively. No correlation was found between acute toxicity and the DVH data. CONCLUSION: This institutional SIB-IMRT protocol using daily image guidance as a precondition for smaller safety margins allows dose escalation to the prostate without increasing acute toxicity.

Basal HIF-1α expression levels are not predictive for radiosensitivity of human cancer cell lines.

BACKGROUND AND PURPOSE: High levels of hypoxia inducible factor (HIF)-1α in tumors are reported to be associated with tumor progression and resistance to therapy. To examine the impact of HIF-1α on radioresistance under normoxia, the sensitivity towards irradiation was measured in human tumor cell lines that differ significantly in their basal HIF-1α levels. MATERIAL AND METHODS: HIF-1α levels were quantified in lysates of H1339, EPLC-272H, A549, SAS, XF354, FaDu, BHY, and CX- tumor cell lines by ELISA. Protein levels of HIF-1α, HIF-2α, carbonic anhydrase IX (CA IX), and GAPDH were assessed by Western blot analysis. Knock-down experiments were performed using HIF-1α siRNA. Clonogenic survival after irradiation was determined by the colony forming assay. RESULTS: According to their basal HIF-1α status, the tumor cell lines were divided into low (SAS, XF354, FaDu, A549, CX-), intermediate (EPLC-272H, BHY), and high (H1339) HIF-1α expressors. The functionality of the high basal HIF-1α expression in H1339 cells was proven by reduced CA IX expression after knocking-down HIF-1α. Linear regression analysis revealed no correlation between basal HIF-1α levels and the survival fraction at either 2 or 4 Gy in all tumor cell lines investigated. CONCLUSION: Our data suggest that basal HIF-1α levels in human tumor cell lines do not predict their radiosensitivity under normoxia.

Induction and repair of DNA double-strand breaks assessed by gamma-H2AX foci after irradiation with pulsed or continuous proton beams.

In particle tumor therapy including beam scanning at accelerators, the dose per voxel is delivered within about 100 ms. In contrast, the new technology of laser plasma acceleration will produce ultimately shorter particle packages that deliver the dose within a nanosecond. Here, possible differences for relative biological effectiveness in creating DNA double-strand breaks in pulsed or continuous irradiation mode are studied. HeLa cells were irradiated with 1 or 5 Gy of 20-MeV protons at the Munich tandem accelerator, either at continuous mode (100 ms), or applying a single pulse of 1-ns duration. Cells were fixed 1 h after 1-Gy irradiation and 24 h after 5-Gy irradiation, respectively. A dose-effect curve based on five doses of X-rays was taken as reference. The total number of phosphorylated histone H2AX (gamma-H2AX) foci per cell was determined using a custom-made software macro for gamma-H2AX foci counting. For 1 h after 1-Gy 20-MeV proton exposures, values for the relative biological effectiveness (RBE) of 0.97 ± 0.19 for pulsed and 1.13 ± 0.21 for continuous irradiations were obtained in the first experiment 1.13 ± 0.09 and 1.16 ± 0.09 in the second experiment. After 5 Gy and 24 h, RBE values of 0.99 ± 0.29 and 0.91 ± 0.23 were calculated, respectively. Based on the gamma-H2AX foci numbers obtained, no significant differences in RBE between pulsed and continuous proton irradiation in HeLa cells were detected. These results are well in line with our data on micronucleus induction in HeLa cells.

Salvage radiotherapy in patients with recurrent esophageal carcinoma.

PURPOSE: The feasibility and effectiveness of radiotherapy in the management of recurrent esophageal carcinoma (REC) is reported. PATIENTS AND METHODS: A consecutive cohort of 54 patients with rcT1-4, rcN0-1, or cM0 recurrent esophageal carcinoma (69% squamous cell carcinoma, 31% adenocarcinoma) was treated between 1988 and 2010. The initial treatment for these patients was definitive radiochemotherapy, surgery alone, or neoadjuvant radiochemotherapy + surgical resection in 8 (15%), 33 (61%), and 13 (24%) patients, respectively. The median time to recurrence from initial treatment was 19 months (range 4-79 months). The site of the recurrence was anastomotic or local, nodal, or both in 63%, 30%, and 7% of patients, respectively. Salvage radio(chemo)therapy was carried out with a median dose of 45 Gy (range 30-68 Gy). RESULTS: Median follow-up time for surviving patients from the start of R(C)T was 38 months (range 10-105 months). Relief of symptoms was achieved in 19 of 28 symptomatic patients (68%). The median survival time was 12 months (95% confidence interval (CI) 7-17 months) and the median recurrence-free interval was 8 months (95% CI 4-12 months). The survival rates at 1, 2, and 3 years were 55 ± 7%, 29 ± 6%, and 19 ± 5%, respectively. The recurrence-free survival rates at 1, 2, and 3 years were 44 ± 7%, 22 ± 6%, and 15 ± 5%, respectively. A radiation dose ≥ 45 Gy and conformal RT were associated with a better prognosis. CONCLUSION: RT is feasible and effective in the management of recurrent esophageal carcinoma, especially for relief of symptoms. Toxicity is in an acceptable range. The outcome of REC is poor; however, long-term survival of patients with recurrent esophageal carcinoma after radiochemotherapy might be possible, even with a previous history of radiotherapy in the initial treatment. If re-irradiation of esophageal carcinoma is contemplated, three-dimensional conformal techniques and a minimum total dose of 45 Gy are recommended.