Predictor Of Local Failure Research Articles

Diffusion-Weighted Imaging of Nasopharyngeal Carcinoma: Can Pretreatment DWI Predict Local Failure Based on Long-Term Outcome?

Pretreatment prediction of patients with nasopharyngeal carcinoma who will fail conventional treatment would potentially allow these patients to undergo more intensive treatment or closer posttreatment monitoring. The aim of the study was to determine the ability of pretreatment DWI to predict local failure in patients with nasopharyngeal carcinoma based on long-term clinical outcome. One hundred fifty-eight patients with pretreatment DWI underwent analysis of the primary tumor to obtain the ADC mean, ADC skewness, ADC kurtosis, volume, and T-stage. Univariate and multivariate analyses using logistic regression were performed to compare the ADC parameters, volume, T-stage, and patient age in primary tumors with local failure and those with local control, by using a minimum of 5-year follow-up to confirm local control. Local control was achieved in 131/158 (83%) patients (range, 60.3-117.7 months) and local failure occurred in 27/158 (17%) patients (range, 5.2-79.8 months). Compared with tumors with local control, those with local failure showed a significantly lower ADC skewness (ADC values with the greatest frequencies were shifted away from the lower ADC range) (P = .006) and lower ADC kurtosis (curve peak broader) (P = .024). The ADC skewness remained significant on multivariate analysis (P = .044). There was a trend toward higher tumor volumes in local failure, but the volume, together with T-stage and ADC mean, were not significantly different between the 2 groups. Pretreatment DWI of primary tumors found that the skewness of the ADC distribution curve was a predictor of local failure in patients with nasopharyngeal carcinoma, based on long-term clinical outcome.

Margin to tumor thickness ratio – A predictor of local recurrence and survival in oral squamous cell carcinoma

To assess whether small oral squamous cell carcinomas (OSCC) require the same margin clearance as large tumors. We evaluated the association between the ratio of the closest margin to tumor size (MSR) and tumor thickness (MTR) with local control and survival. The clinicopathologic and follow up data were obtained for 501 OSCC patients who had surgical resection with curative intent at our institution. MTR and MSR were computed and their associations with local control and survival were assessed using multivariable Cox-regression model. Survival curves were generated using the Kaplan-Meier method. MTR was a better predictor of disease control than MSR. MTR was a predictor of local failure (p=0.033) and disease specific death (p=0.038) after adjusting for perineural invasion, lymphovascular involvement, nodal status, and radiotherapy. A threshold MTR value of 0.3 was identified, above which the risk of local recurrence was low. The ratio of margin to tumor thickness was an independent predictor for local recurrence and disease specific death in this cohort. A MTR>0.3 can serve as a useful tool for adjuvant therapy planning as it combines tumor thickness and margin clearance, two well established prognostic factors. The minimum safe margin can be calculated by multiplying the tumor thickness by 0.3. Further prospective studies in other institutions are warranted to confirm the prognostic utility of MTR and assess the generalizability of our threshold values.

Clinical and Molecular Predictors of Local Failure After SBRT for Liver Metastases: A Secondary Analysis of a Prospective Phase II Trial

Clinical and Molecular Predictors of Local Failure After SBRT for Liver Metastases: A Secondary Analysis of a Prospective Phase II Trial

Cerebellar Location as an Independent Predictor for Local Failure After Treatment With Stereotactic Radiosurgery for Brain Metastases

Cerebellar Location as an Independent Predictor for Local Failure After Treatment With Stereotactic Radiosurgery for Brain Metastases

Prognostic value of the primary lesion apparent diffusion coefficient (ADC) in nasopharyngeal carcinoma: a retrospective study of 541 cases.

The prognostic value of the primary lesion pretreatment apparent diffusion coefficient (ADC), which is obtained by diffusion-weighted magnetic resonance imaging (MR-DWI), remains unknown in nasopharyngeal carcinoma (NPC). Thus, to investigate whether the pretreatment ADC value as measured from the primary site on MR-DWI is an independent prognostic factor in NPC, we retrospectively reviewed a cohort of 541 patients with histologically-proven stage I-IVB NPC. All patients underwent MRI using a 3-Tesla system (Trio Tim; Siemens, Erlangen Germany). To calculate ADC, the primary lesion was designated on the ADC map at the level of the largest tumor diameter to cover most of the lesion, avoiding cystic or necrotic components. Median and mean (±SD) pretreatment ADC were 0.713 and 0.716 ± 0.079 × 10−3 mm2/s, respectively. Univariate and multivariate analysis confirmed high pretreatment ADC was a good prognostic factor for poor local relapse-free survival and disease-free survival. Furthermore, the area under the ROC curve for prediction of local failure significantly increased when pretreatment ADC was combined with T classification (P = 0.004). Thus, pretreatment ADC might provide useful information for predicting outcome and selecting high-risk patients appropriate for more aggressive therapy. Further studies are warranted to investigate the biological basis of this observation.

Postoperative radiation therapy for osseous metastasis: Outcomes and predictors of local failure

PurposeTo evaluate patterns and predictors of local failure in patients undergoing postoperative radiation therapy (RT) for osseous metastases. Methods and materialsPatients undergoing postoperative RT for bone metastases between June 2008 and January 2012 were retrospectively reviewed. Patterns of local failure were assessed, and Fine and Gray’s univariable and multivariable analyses (MVA) were used to evaluate factors associated with local progression, including dose intensity of RT (biological equivalent dose, BED, Gy10) and percent coverage of the surgical hardware by the RT fields. Additional predictors were similarly assessed, including patient (eg, age, performance status), disease (eg, tumor type, metastasis site), and treatment (eg, interval from surgery to RT) characteristics. ResultsA total of 82 cases were followed for a median of 4.3 months (11.5 months among living patients) after treatment completion. Median BED was 39 Gy10 (range, 14-60), and RT fields covered an average of 71% (standard deviation, 26%) of the hardware. Fourteen cases (17%) experienced local progression. Although most (71%) failures occurred within the RT fields, 29% occurred marginally or out of field, but adjacent to surgical hardware. Increasing coverage of the surgical hardware by RT fields was associated with a reduced risk of local failure in MVA (hazard ratio [HR], 0.10; 95% confidence interval [CI], 0.012-0.82; P = .03), whereas a greater risk of failure was seen with increasing time between surgery and RT (HR, 1.03; 95% CI, 1.01-1.06; P = .01). Extremity rather than spinal site trended toward a greater risk of failure but did not reach significance (HR, 3.79; 95% CI, 0.96-14.89; P = .057). BED ≥39 Gy10 did not predict local failure (P = .51) in MVA. ConclusionsCurrent strategies achieve good outcomes after postoperative RT for osseous metastases. Greater coverage of the surgical hardware with RT fields and avoiding delays between surgery and postoperative RT should be considered to reduce recurrence risk for patients with bone metastases requiring surgical stabilization.

Primary Gross Tumor Volume is an Important Prognostic Factor in Locally Advanced Esophageal Cancer Patients Treated with Trimodality Therapy.

This study investigated the relationship between tumor volume and outcomes in patients receiving trimodality therapy for locally advanced esophageal cancer. Between 2001 and 2012, 67 patients treated for esophageal cancer with chemoradiotherapy followed by esophagectomy who had available gross tumor volume (GTV) information were analyzed (35 node-negative, 32 node-positive patients with primary and nodal GTV contoured as separate regions of interest). All gross tumor volumes (GTVs) were contoured at the time of radiotherapy treatment planning. GTV optimal cutoff values were determined with receiver operating characteristic analysis and deemed significant when χ (2) analysis demonstrated differences in examined prognostic variables. Overall survival (OS) and progression-free survival (PFS) were analyzed using the Cox proportional hazards model. GTVprimary (P = 0.034) and N stage were significant multivariate predictors for improved local control; GTVprimary was the only multivariate predictor of PFS (P = 0.0299) and OS (P = 0.001228) at 5 years. Univariate predictors of 5-year PFS and OS included GTVprimary, node number, and metastatic lymph node ratio. GTVprimary >85 cc was the best predictor for local failure (33.3 %; 8.7 % if ≤85 cc). GTVprimary >46 cc correlated with an increased risk of 5-year distant failure (37.1 %; 6.7 % if ≤46 cc). GTVprimary was a significant multivariate predictor for improved local control, PFS, and OS. GTVprimary is a more powerful predictor of patient outcomes than traditional TNM staging and should be part of the decision-making process when determining optimal local and systemic options for patients with locally advanced esophageal cancer.

Impact of Pretreatment Modified Glasgow Prognostic Score on Survival in Chemoradiation Therapy for Locally Advanced Pancreatic Cancer

operating characteristic (ROC) curves were generated for MRI use as a predictor of LF. Results: Twenty-two patients (62.9%) had an MRI incorporated into GTVdelineation and 13 patients (37.1%) had a CT alone. 10 (28.6%) patients had BR tumors while 25 (71.4%) had LAPC. There was a median tumor size of 3.5cm (range 1.4-5.6). 5 (14.3%) patients underwent upfront CRT while 28 (80.0%) patients underwent induction chemotherapy followed by CRT. Chemotherapy agents used in CRT included infusional 5-fluorouracil (11.4%), gemcitabine (37.1%), oral capecitabine (42.9%) and other agents (5.7%). Median RT dose was 50.4 Gy (range 36-55.8) and 74.3% had fractionation of 1.8 Gy. 17 patients (48.6%) had an in-field boost incorporated into the treatment plan. 7 (20.0%) patients received standard IMRT while 28 (80.0%) patients underwent VMAT. Mean PTV expansion was 1.3cm for the CT group and 1.6cm for the CT-MRI group (pZ 0.2). Median follow-up was 11.9 months for the CT-MRI group and 15.4 months for the CT group. Overall local control rate was 68.6% (24/35 patients). Local control rates were 46.2% (6/13) in the CT group and 81.8% (18/22) in the MRI group (pZ .028). On stepwise logistic regression, lack of MRI use was the only predictor of local failure (adjusted OR 5.95 [95% CI Z 1.2228.95]; p Z .027) with an AUC of 70%. Conclusions: Incorporation of an MRI into GTV-delineation for radiation therapy treatment planning is associated with significantly higher local tumor control rates than seen with CT only-based planning among patients undergoing IMRT for borderline or unresectable pancreatic cancer. Author Disclosure: L. Colbert: None. W.A. Hall: None. C. Mosley: None. C. Seldon: None. P. Mittal: None. J. Switchenko: None. J. Mikell: None.G. Mavraj: None. D.S. Yu: None. J.C. Landry: None.W. Curran: None.

WE-G-BRD-09: Prediction of Local Control/Failure by Using Feature Histogram Selection in Follow-Up T2-Weighted MR Image in Spinal Tumors After Stereotactic Body Radiation Therapy

Purpose: In follow-up T2-weighted MR images of spinal tumor patients treated with stereotactic body radiation therapy (SBRT), high intensity features embedded in dark surroundings may suggest a local failure (LF). We investigated image intensity histogram in imaging features to predict LF and local control (LC). Methods: Sixty-seven spinal tumors were treated with SBRT at our institution with scheduled follow-up MR T2-weighted (TR 3200–6600ms; TE 75-132ms) imaging. The LF group included 10 tumors with 8.7 months median follow-up, while the LC group had 11 tumors with 24.1 months median follow-up. The follow-up images were fused to the planning CT. Image intensity histograms of the GTV were calculated. Voxels in greater than 90% (V90), 80% (V80), and peak (Vpeak) of the histogram were grouped into sub-ROIs to determine the best feature histogram. The intensity of each sub-ROI was evaluated using the mean T2-weighted signal ratio (intensity in sub-ROI / intensity in normal vertebrae). An ROC curve in predicting LF for each sub-ROI was calculated to determine the best feature histogram parameter for LF prediction. Results: Mean T2-weighted signal ratio in the LF group was significantly higher than that in the LC group for all sub-ROIs (1.1±0.4 vs. 0.7±0.2, 1.2±0.4 vs. 0.8±0.2, 1.4±0.5more » vs. 0.8±0.2, for V90, V80, and Vpeak, p=0.02, 0.02, and 0.002, respectively). The corresponding areas-under-curve (AUC) of ROC were 0.78, 0.80, and 0.87, p=0.02, 0.03, 0.004, respectively. No correlation was found between T2-weighted signal ratio in Vpeak and follow-up time (Pearson's ρ=0.15). Conclusion: Increased T2-weighted signal can be used to identify local failure while decreased signal indicates local control after spinal SBRT. By choosing the best histogram parameter (here the Vpeak), the AUC of the ROC can be substantially improved, which implies reliable prediction of LC and LF. These results are being further studied and validated with large multi-institutional data.« less

Diffusion-weighted MR imaging in laryngeal and hypopharyngeal carcinoma: association between apparent diffusion coefficient and histologic findings.

To investigate the relationship between the histologic characteristics of head and neck squamous cell carcinoma and apparent diffusion coefficient (ADC) at diffusion-weighted magnetic resonance (MR) imaging. The institutional ethics committee approved this study and waived informed consent. In head and neck squamous cell carcinoma, local failure after chemotherapy and/or radiation therapy correlates with pretreatment ADC. However, the histopathologic basis of this correlation remains unclear. In this study, 16 patients with head and neck squamous cell carcinoma were enrolled (median age, 60 years; range, 49-78 years). Before undergoing total laryngectomy, patients underwent 1.5-T diffusion-weighted MR imaging. After resection, whole-mount hematoxylin-eosin-stained sections were registered to the MR images. Cellular density; nuclear, cytoplasmic, and stromal area; and nuclear-cytoplasmic ratio within the tumor were calculated by using image-based segmentation on four consecutive slices. Mean ADC of the corresponding tumor region was calculated. Spearman correlations between ADC and histologic characteristics were calculated. ADC was significantly and inversely correlated with cell density (n = 16, r = -0.57, P = .02), nuclear area (n = 12, r = -0.64, P = .03), and nuclear-cytoplasmic ratio (n = 12, r = -0.77, P ≤ .01). ADC was significantly and positively correlated with percentage area of stroma (n = 12, r = 0.69, P = .01). Additionally, the percentage area of stroma was strongly interdependent with the percentage area of nuclei (n = 12, r = -0.97, P ≤ .01). ADC was significantly correlated with cellularity, stromal component, and nuclear-cytoplasmic ratio. The positive correlation of ADC and stromal component suggests that the poor prognostic value of high pretreatment ADC might partly be attributed to the tumor-stroma component, a known predictor of local failure.

A Dosimetric Evaluation of Target Coverage as a Predictor of Local Failure Following Stereotactic Body Radiation Therapy for Spinal Tumors

To perform a dosimetric analysis of target coverage and determine parameters predictive for local failure (LF) in patients undergoing spinal stereotactic body radiation therapy (sSBRT).Materials and Methods: Sixty-seven spinal tumors in 59 patients were treated with image-guided linac-based sSBRT from 2008-2012. Median prescription dose was 18Gy (8-35) delivered in 1-5 fractions (87% single-fraction). Prescription dose was targeted to cover ≥ 80% of PTV within spinal cord (SC) dose constraints (9/11Gy to 0.1cc SC/SC+2mm). Twelve tumors had local failure (LF, median time-to-failure 3.7 months) and were compared to 14 tumors with >1-year follow-up and local control (LC). Univariate and multivariate analyses were performed to determine parameters predictive of LF. Median follow-up was 7.4 months and 24.7 months for LF and LC, respectively. Post-SBRT, 42% of LF patients had neurological symptoms due to tumor progression. No patients developed post-SBRT myelopathy. Pre-treatment PTV volumes were not statistically different (median/mean/range 61.8/74.5/19.9-206.4cc for LF vs 39.4/47.1/10.3-119.7cc for LC; p=0.13). LF tumors had larger volumes receiving <80% of prescription dose (5.2cc vs 1.9cc, p=0.02) and larger overlap volume between GTV/SC within 2 and 3mm (p=0.01/p=0.007). LF tumors had lower GTV minimum dose (5.6 vs 8.5Gy, p=0.001) and smaller GTV to SC distance (0.06 vs 0.19mm, p=0.049). Maximum SC doses were not statistically different (6.4Gy LC vs 9.2Gy LF, p=0.33). GTV minimum dose was predictive of LF, with a trend for overlapping GTV/SC volume within 2mm. Minimum GTV dose, PTV volume receiving <80% prescription dose, smaller GTV-SC distance, and large overlapping volume of PTV/SC are predictive of LF after SBRT. Given the absence of SC toxicity but neurological progression upon LF, less conservative SC constraints should be considered.

PD-0607: Diffusion Weighted MRI for prediction of local failure in locally advanced cervical cancer

PD-0607: Diffusion Weighted MRI for prediction of local failure in locally advanced cervical cancer

Transanal Endoscopic Microsurgery for Residual Rectal Cancer (ypT0-2) Following Neoadjuvant Chemoradiation Therapy

Significant tumor downstaging among patients with rectal cancer following neoadjuvant chemoradiation has raised the issue of offering patients with small residual cancers restricted to the bowel wall an alternative treatment strategy to total mesorectal excision. Transanal endoscopic microsurgery may allow proper primary tumor resection with promising oncological outcomes, less postoperative morbidity, and minimal long-term sexual, urinary, and fecal continence disorders in comparison with radical resection. The aim of this study was to determine the oncological outcomes of patients with residual rectal cancers restricted to the rectal wall (ypT0-2) following neoadjuvant chemoradiation and transanal endoscopic microsurgery. This study considered a prospective cohort of patients with residual rectal cancers following neoadjuvant chemoradiation treated by transanal endoscopic microsurgery and no additional systemic therapy. This study was a single-institution experience. Patients with adenocarcinoma of the rectum located no more than 7 cm from the anal verge and endorectal ultrasound- or magnetic resonance-staged cT2-4N0-2M0 treated by neoadjuvant chemoradiation (50.4-54 Gy and 5-fluorouracil-based chemotherapy) were eligible for the study. Patients with small residual tumors (≤3 cm) radiologically staged ycT0-2N0 were treated by transanal endoscopic microsurgery. Transanal endoscopic microsurgery was performed. The primary outcome measured was local recurrence. Of the 27 patients treated by transanal endoscopic microsurgery, 3 had ypT0, 6 had ypT1, and 18 had ypT2 cancers. All patients underwent R0 transanal endoscopic microsurgery excision. Local recurrence was observed in 4 (15%) patients after a median follow-up of 15 months. Only lymphovascular invasion was an independent predictive factor for local failure (p = 0.04). Tumor size, ypT status, T-status downstaging, lateral/radial margins, and tumor regression grade were not predictors of local failure. This study was limited by the small sample size and limited follow-up. A local failure rate of 15% after transanal endoscopic microsurgery for patients with residual rectal cancers restricted to the bowel wall (ypT0-2) may limit the indication of this procedure to highly selected patients as an alternative to standard radical total mesorectal excision.

Head and Neck Squamous Cell Carcinoma: Diagnostic Performance of Diffusion-weighted MR Imaging for the Prediction of Treatment Response

To determine the diagnostic performance of diffusion-weighted (DW) imaging for the prediction of treatment failure in primary head and neck squamous cell carcinoma (HNSCC). The study was approved by the local institutional ethics committee and conducted with informed written consent in patients with primary HNSCC treated with radiation therapy and chemotherapy. DW imaging of the primary tumor was performed before treatment in 37 patients and was repeated within 2 weeks of treatment in 30 patients. Histograms of apparent diffusion coefficients (ADCs) were analyzed, and mean ADC, kurtosis, skewness, and their respective percentage change were correlated for local failure and local control at 2 years by using the Student t test. Univariate and multivariate analyses of the ADC parameters, T stage, and tumor volume were performed by using logistic regression for prediction of local failure. Local failure occurred in 16 of 37 (43%) patients and local control occurred in 21 of 37 (57%) patients. Pretreatment ADC parameters showed no correlation with local failure. There was significant intratreatment increase in mean ADC and a decrease in skewness and kurtosis (P < .001, P < .001, P = .024, respectively) for the whole group of patients when compared with those before treatment. During treatment, primary tumors showed a significantly lower increase in percentage change of mean ADC, higher skewness, and higher kurtosis for local failure than for local control (P = .016, .015, and .040, respectively). These ADC parameters also were significant for predicting local failure with use of univariate but not multivariate analysis. Early intratreatment DW imaging has the potential to allow prediction of treatment response at the primary site in patients with HNSCC.

An approach to identify, from DCE MRI, significant subvolumes of tumors related to outcomes in advanced head‐and‐neck cancera)

To develop and investigate a method to identify, from dynamic contrast enhanced (DCE) MRI, significant subvolumes of tumors related to treatment outcomes. A method, called global-initiated regularized local fuzzy clustering, was proposed to identify subvolumes of head-and-neck cancers (HNC) from heterogeneous distributions of tumor blood volume (BV) and blood flow (BF) for assessment of therapy response. BV and BF images, derived from DCE MRI, of 14 patients with advanced HNC were obtained before treatment and 2 weeks after the start of 7-week chemoradiation therapy (chemo-RT). The delineated subvolumes of tumors with low BV or BF before and during treatment were evaluated for their associations with local failure (LF). Receiver operating characteristic (ROC) analysis was used to assess performance of the method for prediction of local failure of HNC. The sizes of the subvolumes of primary tumors with low BV, delineated by our method before and week 2 during treatment, were significantly greater in the patients with LF than with local control (LC) (p = 0.02 for pre-RT and 0.01 for week 2). While the total primary tumor volumes were reduced from baseline to week 2 during therapy to a similar extent for both the patients with LF and LC, the percentage decreases in the subvolumes of the primary tumors with low BV in the same time interval were significantly smaller for the patients with LF than those with LC (p < 0.05). ROC analysis shows that for any given sensitivity, the subvolume of the tumor with low BV week 2 during treatment has greater specificity for prediction of local failure than the pretreatment total tumor volume, the percentage change in the tumor volume week 2 during treatment, or the change in the averaged BV values of the entire tumor week 2 during therapy. We developed a method to identify the significant subvolumes of primary tumors related to local failure. Large poorly perfused subvolumes of primary or nodal HNC before treatment and persisting during the early course of chemo-RT have the potential for prediction of local or regional failure, and could be candidates for local dose intensification.

Combined PET/CT image characteristics for radiotherapy tumor response in lung cancer

Prediction of local failure in radiotherapy patients with non-small cell lung cancer (NSCLC) remains a challenging task. Recent evidence suggests that FDG-PET images can be used to predict outcomes. We investigate an alternative multimodality image-feature approach for predicting post-radiotherapy tumor progression in NSCLC. We analyzed pre-treatment FDG-PET/CT studies of twenty-seven NSCLC patients for local and loco-regional failures. Thirty-two tumor region features based on SUV or HU, intensity-volume-histogram (IVH) and texture characteristics were extracted. Statistical analysis was performed using Spearman's correlation (rs) and multivariable logistic regression. For loco-regional recurrence, IVH variables had the highest univariate association. In PET, IVH-slope reached rs=0.3426 (p=0.0403). Motion correction slightly improved correlation of texture features. In CT, coefficient of variation had the highest association rs=-0.2665 (p=0.0871). Similarly for local failure, a CT-IVH parameter reached rs=0.4530 (p=0.0105). For loco-regional and local failures, a 2-parameter model of PET-V(80) and CT-V(70) yielded rs=0.4854 (p=0.0067) and rs=0.5908 (p=0.0013), respectively. Addition of dosimetric variables provided improvement in cases of loco-regional but not local failures. We proposed a feature-based approach to evaluate radiation tumor response. Our study demonstrates that multimodality image-feature modeling provides better performance compared to existing metrics and holds promise for individualizing radiotherapy planning.

POD-07.02 Positive Surgical Margin at Bladder Neck Is an Independant Predictor of Local Failure and Prostate Cancer Mortality in pT3-Prostate Cancer. Results of a Prospective Single Institution Series

POD-07.02 Positive Surgical Margin at Bladder Neck Is an Independant Predictor of Local Failure and Prostate Cancer Mortality in pT3-Prostate Cancer. Results of a Prospective Single Institution Series

Increased Recurrences Using Intensity-Modulated Radiation Therapy in the Postoperative Setting

To determine the pattern of failures following intensity modulated radiation therapy for head and neck cancer. A retrospective single institution study. Between May 2001 and June 2008, 176 patients with head and neck cancer were treated with intensity modulated radiation therapy at Fox Chase Cancer Center. Ninety-five (54%) were squamous cell carcinoma treated with curative intent. Tumor and nodal stage, tobacco history, definitive versus postoperative therapy (PORT), addition of chemotherapy and RT duration were analyzed for association with patterns of failure. In patients treated with definitive radiation, high-risk PTV (PTV1) was prescribed to 70 Gy and low-risk PTV (PTV2) to 56 Gy. In the PORT setting, PTV1 was prescribed to 60 to 66 Gy and PTV2 to 54 Gy. Patterns of failure were assessed. Local failure (LF) was defined as the persistence of disease or recurrence within PTV1, marginal failure as recurrence at the region of high-dose falloff, and regional failure as nodal recurrence within PTV2. Median follow-up was 20 months (range: 1-117). Median age was 60 years (range: 28-88), with 80% smokers and 81% stage III or IV. PORT was given to 29% and 71% were treated definitively, with concurrent Cisplatin used in the majority. Three-year local and locoregional (LR) failure rates were 9% and 16%, respectively. Failures occurred in 14 patients: 8 local, 3 regional, 1 LR, and 2 distant. Five of the 8 LF and all 3 marginal failures were observed in PORT cohort. On univariate analysis, the only predictor of LF was the use of PORT (P = 0.06). LR control was 66% for PORT versus 87%, 97% for definitive RT and chemoRT. Local, regional failures were more common following PORT related to an increased risk of marginal failures.

Progressive Damage of Unidirectional Composite Panels

This work focuses on the numerical simulation of damage and fracture of unidirectional fiber-reinforced composite structures using the finite element method. A computational model is presented which can predict initial failure and is capable of the simulation of the subsequent process of local material damage up to final fracture. This procedure also known as progressive failure analysis originally combines Puck's failure criterion for the prediction of local failure and an innovative stiffness degradation approach for the simulation of resulting damage. The performance of the proposed model is demonstrated on examples of tensile tests of single-ply fiber-reinforced panels having different fiber orientations with and without stress concentrators. The numerical simulation is performed both as quasi-static and transient analysis and it involves identification and repetitive adjustment of material properties. The comparison of the results from experiment and from the simulation yields satisfactory agreement.

Salvage-radikale Prostatektomie

Following external beam radiation and interstitial radiation for prostate cancer, between 30% and 50% of the patients experience locoregional recurrence of their cancer. Although radical salvage prostatectomy is a secondary treatment option with curative intent, so far only a few hundred patients (<2%) worldwide have undergone this operation. The subject of this paper is a review of the world literature with reference to the frequency with this operation is performed and the technique, and also the prospects of success and possible complications. After radiotherapy, approximately 30% of biopsies are positive. Nonetheless, only 536 cases of salvage radical prostatectomy had been reported in the world literature up to 2005. The diagnosis of a local recurrence was always confirmed by rectal punch biopsy, pelvic CT and bone scintigraphy. Salvage radical prostatectomy with or without nerve sparing, with pelvic lymphadenectomy and, in some patients with cystectomy plus urinary diversion was the operative treatment applied. Following secondary treatment after radiotherapy (RT), three parameters have been consistently identified as predictors of local failure: PSA nadir, time to nadir and PSA doubling time; clinical stage and type of first-line treatment are not helpful in predicting failure. The 5-year biochemical relapse-free survival rates are 77%, 71% and 28% for stages pT2, pT3a and pT3b/pN1, respectively. The success rate for salvage radical prostatectomy is thus similar to that for de novo radical prostatectomy for the same stages. In the past salvage radical prostatectomy following radiotherapy had a high complication rate. A salvage radical prostatectomy with curative intent is a radical prostatectomy following radiotherapy also performed with curative intent. The reasons for the few literature reports of salvage RPX are: (1) oncological misgivings (too long a period of observation of PSA by the radiation oncologist/urologist; (2) misgivings to do with surgical technique, as the operation is technically challenging and involves a high risk of complications, especially incontinence. In recent times the comorbidity rate has become acceptable in cases in which the indications have been correctly observed. We believe that salvage prostatectomy should be considered only for patients in good general health whose life expectancy is over 10 years and who have recurrent cancer confirmed by punch biopsy 1 year or longer after the completion of radiotherapy and whose cancer was initially in an early (T1-2) clinical stage before their radiotherapy. Ideally, serum PSA should be less than 10 ng/ml both initially (before radiotherapy) and before salvage surgery. In addition, patients should be highly motivated and able to accept the surgical morbidity (50% incontinence rate).