Arrowhead design ultrasonic tip as a supplementary tool for canal debridement.

AIM: To investigate the shaping and cleaning performance of the Clearsonic ultrasonic tip as a supplementary tool during the preparation of long oval-shaped root canals through micro-computed tomographic (micro-CT) imaging technology. The Reciproc M-Wire R40 instrument was used as a reference instrumentation technique for comparison. METHODOLOGY: Twenty mandibular incisors with single, straight and long oval-shaped canals were selected and pair-matched by micro-CT scanning. The root canals were prepared with Reciproc R25 and R40 instruments, scanned again in a micro-CT device and randomly allocated into one of the two experimental groups (n = 10), according to the supplementary debridement protocol used: Clearsonic or Reciproc R40 used in a brushing motion against buccal and lingual walls. Noninstrumented canal areas, accumulation of hard-tissue debris (AHTD) and volume of removed dentine were assessed using micro-CT imaging following the supplementary debridement protocols. Data were analysed statistically in two phases using a t-test with a significance level of 5%. RESULTS: In phase-1, there was a significant similarity between the samples regarding the evaluated micro-CT baseline parameters (P > 0.05), validating the anatomical similarity between the tooth pairs. In phase-2, there was a significant difference between the groups for canal volume, surface area, noninstrumented root canal walls and the amount of removed dentine for both absolute and percentage values (P < 0.05), but not for AHTD (P = 0.759). CONCLUSIONS: The Clearsonic tip outperformed the Reciproc R40 instrument as a supplementary debridement protocol as it was associated with significantly greater reduction of noninstrumented root canals walls and consequently a larger amount of removed dentine. Both groups performed similarly regarding the AHTD.

OPTIMA: a phase II dose and volume de-escalation trial for human papillomavirus-positive oropharyngeal cancer.

BACKGROUND: Patients with HPV+ oropharyngeal squamous cell carcinoma were assigned to dose and volume de-escalated radiotherapy (RT) or chemoradiotherapy (CRT) based on response to induction chemotherapy in an effort to limit treatment-related toxicity while preserving efficacy. PATIENTS AND METHODS: Patients were classified as low-risk (≤T3, ≤N2B, ≤10 pack-year history) or high-risk (T4 or ≥N2C or >10 PYH). After three cycles of carboplatin/nab-paclitaxel, response was assessed using Response Evaluation Criteria in Solid Tumors 1.1. Low-risk patients with ≥50% response received 50 Gray (Gy) RT (RT50) while low-risk patients with 30%-50% response or high-risk patients with ≥50% response received 45 Gy CRT (CRT45). Patients with lesser response received standard-of-care 75 Gy CRT (CRT75). RT/CRT was limited to the first echelon of uninvolved nodes. The primary end point was 2-year progression-free survival compared with a historic control of 85%. Secondary end points included overall survival and toxicity. RESULTS: Sixty-two patients (28 low risk/34 high risk) were enrolled. Of low-risk patients, 71% received RT50 while 21% received CRT45. Of high-risk patients, 71% received CRT45. With a median follow-up of 29 months, 2-year PFS and OS were 95% and 100% for low-risk patients and 94% and 97% for high-risk patients, respectively. The overall 2-year PFS was 94.5% and within the 11% noninferiority margin for the historic control. Grade 3+ mucositis occurred in 30%, 63%, and 91% of the RT50, CRT45, and CRT75 groups, respectively (P = 0.004). Rates of any PEG-tube use were 0%, 31%, and 82% for RT50, CRT45, and CRT75 groups, respectively (P < 0.0001). CONCLUSIONS: Induction chemotherapy with response and risk-stratified dose and volume de-escalated RT/CRT for HPV+ OPSCC is associated with favorable oncologic outcomes and reduced acute and chronic toxicity. Further evaluation of induction-based de-escalation in large multicenter studies is justified. CLINICAL TRIAL REGISTRATION: Clinical trials.gov identifier: NCT02258659.

Embedding Anatomical or Functional Knowledge in Whole-Brain Multiple Kernel Learning Models.

Pattern recognition models have been increasingly applied to neuroimaging data over the last two decades. These applications have ranged from cognitive neuroscience to clinical problems. A common limitation of these approaches is that they do not incorporate previous knowledge about the brain structure and function into the models. Previous knowledge can be embedded into pattern recognition models by imposing a grouping structure based on anatomically or functionally defined brain regions. In this work, we present a novel approach that uses group sparsity to model the whole brain multivariate pattern as a combination of regional patterns. More specifically, we use a sparse version of Multiple Kernel Learning (MKL) to simultaneously learn the contribution of each brain region, previously defined by an atlas, to the decision function. Our application of MKL provides two beneficial features: (1) it can lead to improved overall generalisation performance when the grouping structure imposed by the atlas is consistent with the data; (2) it can identify a subset of relevant brain regions for the predictive model. In order to investigate the effect of the grouping in the proposed MKL approach we compared the results of three different atlases using three different datasets. The method has been implemented in the new version of the open-source Pattern Recognition for Neuroimaging Toolbox (PRoNTo).

Study of the response of an ORTEC GMX45 HPGe detector with a multi-radionuclide volume source using Monte Carlo simulations.

A model of an n-type ORTEC GMX45 HPGe detector was created using the MCNPX and the MCNP-CP codes. In order to validate the model, experimental efficiency was compared with the Monte Carlo simulations results. The reference source is a NIST traceable multi-gamma volume source in a water-equivalent epoxy resin matrix (1.15gcm(-3) density) containing several radionuclides: (210)Pb, (241)Am, (137)Cs and (60)Co in a cylinder shape container. Two distances of source bottom to end cap front surface of the detector have been considered. The efficiency for the nearest distance is higher than for longer distance. The relative difference between the measured and the simulated full-energy peak efficiency is less than 4.0% except for the 46.5keV energy peak of (210)Pb for the longer distance (6.5%) allowing to consider the model validated. In the absence of adequate standard calibration sources, efficiency and efficiency transfer factors for geometry deviations and matrix effects can be accurately computed by using Monte Carlo methods even if true coincidence could occur as is the case when the (60)Co radioisotope is present in the source.

Response-adapted volume de-escalation (RAVD) in locally advanced head and neck cancer.

BACKGROUND: Efforts to reduce the late toxicity associated with chemoradiation (CRT) for locally advanced head and neck squamous cell cancer (LA-HNSCC) have focused on radiotherapy (RT) dose de-escalation. In this phase I/II protocol investigating the addition of everolimus to induction chemotherapy (IC), we incorporated a novel response-adapted volume de-escalation (RAVD) approach using IC response to guide the extent of RT volume reduction. PATIENTS AND METHODS: Patients with measurable LA-HNSCC received two cycles of IC (cisplatin, paclitaxel, cetuximab ± everolimus). Patients with ≥50% reduction in the sum of tumor diameters [good response (GR)] received TFHX (paclitaxel, fluorouracil, hydroxyurea, and 1.5 Gy twice daily RT every other week) to a dose of 75 Gy with the single planning target volume (PTV1) encompassing exclusively gross disease. Patients with <50% response [non-response (NR)] were treated with TFHX encompassing PTV1 and the next nodal station at risk (PTV2) to a dose of 45 Gy followed by a sequential boost to PTV1 to a dose of 75 Gy. RESULTS: Ninety-four patients were enrolled. Randomization to everolimus was discontinued on interim analysis after 50 patients due to futility. IC response was evaluable in 89 patients. Thirty-seven patients (41.6%) had GR and 52 (58.4%) had NR. There was a trend for improved progression-free (P = 0.086) but not overall survival (P = 0.94) for GR versus NR. The 2-year PFS and OS were 86.0% and 83.5% for GR and 68.7% and 85.4% for NR, respectively. NR were significantly more likely to undergo G-tube placement during treatment (50.0% GR versus 73.5% NR, P = 0.040) and be G-tube dependent at 6-month follow-up (5.7% GR versus 32.6% NR, P = 0.005). CONCLUSIONS: The addition of everolimus to IC was not beneficial. The elimination of elective nodal coverage in patients with GR to IC did not appear to compromise outcomes and resulted in significantly decreased late toxicity. Further investigation of RAVD is warranted. CLINICALTRIALSGOV: NCT01133678.

Arsenic fractionation in agricultural soil using an automated three-step sequential extraction method coupled to hydride generation-atomic fluorescence spectrometry.

A fully automated modified three-step BCR flow-through sequential extraction method was developed for the fractionation of the arsenic (As) content from agricultural soil based on a multi-syringe flow injection analysis (MSFIA) system coupled to hydride generation-atomic fluorescence spectrometry (HG-AFS). Critical parameters that affect the performance of the automated system were optimized by exploiting a multivariate approach using a Doehlert design. The validation of the flow-based modified-BCR method was carried out by comparison with the conventional BCR method. Thus, the total As content was determined in the following three fractions: fraction 1 (F1), the acid-soluble or interchangeable fraction; fraction 2 (F2), the reducible fraction; and fraction 3 (F3), the oxidizable fraction. The limits of detection (LOD) were 4.0, 3.4, and 23.6 µg L(-1) for F1, F2, and F3, respectively. A wide working concentration range was obtained for the analysis of each fraction, i.e., 0.013-0.800, 0.011-0.900 and 0.079-1.400 mg L(-1) for F1, F2, and F3, respectively. The precision of the automated MSFIA-HG-AFS system, expressed as the relative standard deviation (RSD), was evaluated for a 200 µg L(-1) As standard solution, and RSD values between 5 and 8% were achieved for the three BCR fractions. The new modified three-step BCR flow-based sequential extraction method was satisfactorily applied for arsenic fractionation in real agricultural soil samples from an arsenic-contaminated mining zone to evaluate its extractability. The frequency of analysis of the proposed method was eight times higher than that of the conventional BCR method (6 vs 48 h), and the kinetics of lixiviation were established for each fraction.

Effects of Maytenus ilicifolia on reproduction and embryo-fetal development in Wistar rats.

Maytenus ilicifolia (Celastraceae), popularly known as espinheira-santa, is a native plant from the Atlantic forest and is commonly used in popular medicine to treat inflammation and as an abortifacient. To evaluate the effects of M. ilicifolia on pregnant rats during the organogenic period (T1) or throughout the gestational period (T2), an extract obtained using an acetone-water mixture at a 70:30 ratio was administered via gavage at a dose of 15.11 mg·kg(-1)·day(-1) over 2 treatment periods (T1 and T2). No clinical signs of maternal toxicity were observed. Term fetuses did not present malformations or anomalies as the number of implantations, reabsorptions, live, and dead fetuses were similar to the control group. In conclusion, M. ilicifolia hydroacetonic extract is non-toxic to pregnant rats and appears to not interfere with the progress of embryo-fetal development.

Phase II trial of pemetrexed-based induction chemotherapy followed by concomitant chemoradiotherapy in previously irradiated patients with squamous cell carcinoma of the head and neck.

BACKGROUND: Concurrent chemoreirradiation therapy (CRRT) offers a therapeutic option for patients with locoregionally recurrent squamous cell carcinoma of the head and neck (SCCHN). We hypothesized that response to induction chemotherapy (IC) would improve outcome and predict increased survival. PATIENTS AND METHODS: Subjects with recurrent SCCHN not amenable to standard therapy were eligible. IC consisted of two 28-day cycles of gemcitabine and pemetrexed on days 1 and 14, followed by surgical resection, if appropriate, and/or CRRT consisting of carboplatin, pemetrexed, and single daily fractionated radiotherapy. RESULTS: Thirty-five subjects were enrolled, 31 were assessable for response, with 11 responders [response rate = 35%; 95% confidence interval (CI) 19.2-54.6]. Among 24 subjects who started CRRT, 11 were assessable for radiographic response, 4 complete response, 2 partial response, and 5 progressive disease. Median progression-free survival and overall survival (OS) were 5.5 months (95% CI 3.6-8.3) and 9.5 months (95% CI 7.2-15.4), respectively. One-year OS was 43% (95% CI 26% to 58%). Subjects who responded to IC had improved survival (P = 0.02). Toxic effects included mucositis, dermatitis, neutropenia, infection, hemorrhage, dehydration, and pain. CONCLUSIONS: The combination of pemetrexed plus gemcitabine was active and well tolerated in recurrent SCCHN. Response to IC may help stratify prognosis and offer an objective and dynamic metric in recurrent SCCHN patients being considered for CRRT.

Box-Behnken design: an alternative for the optimization of analytical methods.

The present paper describes fundamentals, advantages and limitations of the Box-Behnken design (BBD) for the optimization of analytical methods. It establishes also a comparison between this design and composite central, three-level full factorial and Doehlert designs. A detailed study on factors and responses involved during the optimization of analytical systems is also presented. Functions developed for calculation of multiple responses are discussed, including the desirability function, which was proposed by Derringer and Suich in 1980. Concept and evaluation of robustness of analytical methods are also discussed. Finally, descriptions of applications of this technique for optimization of analytical methods are presented.

Effect of Lactobacillus delbrueckii on cholesterol metabolism in germ-free mice and on atherogenesis in apolipoprotein E knock-out mice.

Elevated blood cholesterol is an important risk factor associated with atherosclerosis and coronary heart disease. Several studies have reported a decrease in serum cholesterol during the consumption of large doses of fermented dairy products or lactobacillus strains. The proposed mechanism for this effect is the removal or assimilation of intestinal cholesterol by the bacteria, reducing cholesterol absorption. Although this effect was demonstrated in vitro, its relevance in vivo is still controversial. Furthermore, few studies have investigated the role of lactobacilli in atherogenesis. The aim of the present study was to determine the effect of Lactobacillus delbrueckii on cholesterol metabolism in germ-free mice and the possible hypocholesterolemic and antiatherogenic action of these bacteria using atherosclerosis-prone apolipoprotein E (apo E) knock-out (KO) mice. For this purpose, Swiss/NIH germ-free mice were monoassociated with L. delbrueckii and fed a hypercholesterolemic diet for four weeks. In addition, apo E KO mice were fed a normal chow diet and treated with L. delbrueckii for 6 weeks. There was a reduction in cholesterol excretion in germ-free mice, which was not associated with changes in blood or liver cholesterol concentration. In apo E KO mice, no effect of L. delbrueckii was detected in blood, liver or fecal cholesterol. The atherosclerotic lesion in the aorta was also similar in mice receiving or not these bacteria. In conclusion, these results suggest that, although L. delbrueckii treatment was able to reduce cholesterol excretion in germ-free mice, no hypocholesterolemic or antiatherogenic effect was observed in apo E KO mice.

Effect of Lactobacillus delbrueckii on cholesterol metabolism in germ-free mice and on atherogenesis in apolipoprotein E knock-out mice

Elevated blood cholesterol is an important risk factor associated with atherosclerosis and coronary heart disease. Several studies have reported a decrease in serum cholesterol during the consumption of large doses of fermented dairy products or lactobacillus strains. The proposed mechanism for this effect is the removal or assimilation of intestinal cholesterol by the bacteria, reducing cholesterol absorption. Although this effect was demonstrated in vitro, its relevance in vivo is still controversial. Furthermore, few studies have investigated the role of lactobacilli in atherogenesis. The aim of the present study was to determine the effect of Lactobacillus delbrueckii on cholesterol metabolism in germ-free mice and the possible hypocholesterolemic and antiatherogenic action of these bacteria using atherosclerosis-prone apolipoprotein E (apo E) knock-out (KO) mice. For this purpose, Swiss/NIH germ-free mice were monoassociated with L. delbrueckii and fed a hypercholesterolemic diet for four weeks. In addition, apo E KO mice were fed a normal chow diet and treated with L. delbrueckii for 6 weeks. There was a reduction in cholesterol excretion in germ-free mice, which was not associated with changes in blood or liver cholesterol concentration. In apo E KO mice, no effect of L. delbrueckii was detected in blood, liver or fecal cholesterol. The atherosclerotic lesion in the aorta was also similar in mice receiving or not these bacteria. In conclusion, these results suggest that, although L. delbrueckii treatment was able to reduce cholesterol excretion in germ-free mice, no hypocholesterolemic or antiatherogenic effect was observed in apo E KO mice.

Interim storage of spent and disused sealed sources: optimisation of external dose distribution in waste grids using the MCNPX code.

Radioactive sealed sources are in use worldwide in different fields of application. When no further use is foreseen for these sources, they become spent or disused sealed sources and are subject to a specific waste management scheme. Portugal does have a Radioactive Waste Interim Storage Facility where spent or disused sealed sources are conditioned in a cement matrix inside concrete drums and following the geometrical disposition of a grid. The gamma dose values around each grid depend on the drum's enclosed activity and radionuclides considered, as well as on the drums distribution in the various layers of the grid. This work proposes a method based on the Monte Carlo simulation using the MCNPX code to estimate the best drum arrangement through the optimisation of dose distribution in a grid. Measured dose rate values at 1 m distance from the surface of the chosen optimised grid were used to validate the corresponding computational grid model.

Patterns of failure, prognostic factors and survival in locoregionally advanced head and neck cancer treated with concomitant chemoradiotherapy: a 9-year, 337-patient, multi-institutional experience.

BACKGROUND: Locoregionally advanced, stage IV head and neck cancer has traditionally carried a poor prognosis. We sought to assess changes in patterns of failure, prognostic factors for recurrence, and overall outcome, using two different strategies of chemoradiotherapy conducted in prospective, multi-institutional phase II trials. PATIENTS AND METHODS: Three hundred and thirty-seven stage IV patients were treated from 1989 to 1998. We compared locoregional and distant recurrence rates, overall survival and progression-free survival from two different treatment strategies: intensive induction chemotherapy followed by split-course chemoradiotherapy (type 1, n=127), or intensified, split-course, hyperfractionated multiagent chemoradiotherapy alone (type 2, n=210). Univariate and multivariate analyses of 12 chosen covariates were assessed separately for the two study types. RESULTS: The pattern of failure varied greatly between study types 1 and 2 (5-year locoregional failure of 31% and 17% for study types 1 and 2, respectively, P=0.01; 5-year distant failure rate of 13% and 22% for study types 1 and 2, P=0.03). Combined 5-year overall survival was 47% [95% confidence interval (CI) 41% to 53%) and progression-free survival was 60% (95% CI 55% to 66%). Both treatment strategies yielded similar survival rates. Poor overall survival and distant recurrence were best predicted by advanced nodal stage. Locoregional recurrence was extremely rare for patients with T0-T3 tumor stage, regardless of lymph-node stage. CONCLUSIONS: This analysis suggests that pattern of failure in primary head and neck cancer may be dependent upon treatment strategy. Randomized clinical trials of induction chemotherapy are warranted as a means to determine if a decrease in distant metastases can lead to an increase in survival rates in the setting of effective chemoradiotherapy for locoregional control. Additionally, this analysis provides impetus for randomized clinical trials of organ preservation chemoradiotherapy in sites outside the larynx and hypopharynx.

Parathyroid adenoma after radioactive iodine therapy for multinodular goiter.

The development of hyperparathyroidism after radioactive iodine (RAI) therapy has been reported in 38 cases in the literature. However, the development of a parathyroid adenoma after RAI therapy for a hyperfunctioning multinodular goiter has not been reported. This report describes the pathologic and operative finding on a patient with both hyperthyroidism and hyperparathyroidism, which was diagnosed after previous RAI therapy for a toxic, multinodular goiter.

Concomitant infusional paclitaxel and fluorouracil, oral hydroxyurea, and hyperfractionated radiation for locally advanced squamous head and neck cancer.

PURPOSE: To improve local disease control and survival with organ preservation, we conducted a phase II multi-institutional trial with a concomitant taxane-based chemotherapy and hyperfractionated radiation regimen. PATIENTS AND METHODS: Sixty-four patients with locally advanced squamous cancers (stage IV, 98%; N2/3, 81%) were treated on an intensive regimen consisting of 5-day (120-hour) infusions of paclitaxel (20 mg/m(2)/d) and fluorouracil (600 mg/m(2)/d), oral hydroxyurea 500 mg every 12 hours for 11 doses, and radiation 1.5 Gy bid (T-FH2X). Chemoradiation was administered concomitantly on days 1 to 5 of each 14-day cycle. A full treatment course consisted of five cycles during a 10-week period to a total radiation dose of 72 to 75 Gy. RESULTS: The median follow-up for the group is 34 months. At 3 years, progression-free survival is 63%, locoregional control is 86%, and systemic control is 79%; overall survival is 60%. Seventeen patients died of recurrent cancer, two died of second primary cancers, and four died of other causes. Side effects observed include anemia (22% required transfusion), leucopenia (34%, grade 3 to 4), and mucositis (84%, grade 3 to 4). Organ preservation principles were maintained. At 1 year posttreatment, 61% of patients had severe xerostomia and 47% had compromised swallowing. There was little disturbance of speech quality in 97% of patients at the same follow-up point. CONCLUSION: T-FH2X is a highly active and tolerable concomitant chemotherapy and hyperfractionated radiation regimen that induces sustained local tumor control and holds promise for improved survival with organ preservation in high-risk patients. Identification of less toxic therapy and improved distant disease control are needed. T-FH2X should be tested in a randomized trial and compared with a less intensive concomitant regimen that uses once-daily radiation fractionation.

Postoperative necrotizing fasciitis of the thorax in cardiac surgery.

Necrotizing fasciitis is a rare soft tissue infection and a life-threatening emergency, often fatal. Its incidence and management are described plentifully in the medical literature regarding the most common anatomical sites involved like the abdomen, lower and upper limbs, and perineum. However, available data and case reports of chest wall necrotizing fasciitis after thoracic procedures are scarce, mainly after major cardiac operations. We report and discuss a case of necrotizing fasciitis of the chest wall occurring in the immediate postoperative period of a cardiac procedure, and include a brief review of the concepts, pathophysiology, and treatment reported in the medical literature. We emphasize the need for early diagnosis and urgent and effective surgical debridement. Of importance is the fact that we have not found any references in the literature to cases similar or equal to the one we describe here, which occurred in the postoperative period of a cardiac procedure.

Gelatin intake increases the atheroma formation in apoE knock out mice.

The effect of gelatin ingestion on cholesterol metabolism and on atheroma formation was evaluated in both wild type (n=14) and apoprotein E (apoE) knock out (apoE(-/-)) (n=20) C57BL/6 7-week-old mice. Animals were fed a cholesterol-free isoproteic semi-purified diet containing 20% of casein (control diet) or 10% of casein plus 10% of gelatin (gel diet) for 8 weeks. In wild type mice, dietary gelatin caused a reduction in the serum triacylglycerols levels associated with an increase in the fecal excretion. No difference in blood cholesterol was seen at the sixth week of experiment. At the eighth week of experiment, there was a modest but significant reduction of serum total and high density lipoprotein (HDL) cholesterol in apoE(-/-) mice fed on gel diet compared to the control. Total cholesterol/HDL cholesterol ratio was 2-fold higher in the gel group than that seen in the control group (14.39 and 7.84, respectively). Histological analyzes showed a 2.2-fold increase in the dimension of the atherosclerotic plaques in the proximal aorta in apoE(-/-) mice fed on a gel diet compared to those fed on a control diet. The gel diet also promoted a reduction in the fecal excretion of bile acids. Hepatic cholesterol was similar in both groups. In conclusion, although gelatin reduced total serum cholesterol, this reduction was associated to a decrease of HDL cholesterol and consequent increase of total cholesterol/HDL cholesterol ratio, resulting in an acceleration of atherogenesis.

Salvage treatment for recurrent squamous cell carcinoma of the oral cavity.

BACKGROUND: Squamous cell carcinoma (SCCA) of the oral cavity recurs with a frequency of 25%-48%, a fact that usually portends a poor prognosis. Recent studies have reported salvage cure rates as high as 67%. Investigators have also claimed that restaging recurrent tumors provides useful prognostic information, although this has not been demonstrated with tumors of the oral cavity. The purposes of this study were: (1) to report the patterns of recurrent SCCA of the oral cavity; (2) to examine the benefit of restaging oral cavity tumors, and (3) to compare different treatment modalities in the management of recurrent SCCA of the oral cavity. Materials and Methods Thirty-eight patients who developed recurrent SCCA of the oral cavity were reviewed. Salvage treatment consisted of surgery, chemotherapy, radiation therapy, or a combination of these modalities. Survival analysis was based on the stage of the primary and recurrent tumors and the type of salvage treatment received. RESULTS: The overall recurrence rate was 28%. Local recurrence was most common (58%) followed by locoregional (27%) and regional recurrence (16%). Patients who recurred more than 6 months after completion of their primary treatment had improved survival compared with those who recurred within 6 months of initial treatment. Individuals with stage I-II primary tumors had significantly improved salvage time and total survival time compared with those with stage III-IV primary tumors (p < 0.005 and p < 0.001). Conversely, the stage of the recurrent tumor was not predictive of either improved salvage time or total survival time. Patients who underwent salvage surgery had significantly improved salvage time and total survival time compared with those who received chemotherapy and/or radiation therapy (p < 0.001 and p < 0.002). The overall salvage cure rate was 21%. Neither the stage of the primary or recurrent tumors nor the type of salvage treatment received significantly correlated with an improved cure rate. However, the group of patients who underwent salvage surgery approached a statistically significant improvement in cure rate (p = 0.08). CONCLUSIONS: Squamous cell carcinoma of the oral cavity is most likely to recur at the primary site. The stage of the primary tumor is significantly correlated with survival even after recurrence, but the stage of the recurrent tumor is not significantly correlated with survival. Patients most likely to benefit from retreatment are those who (1) have primary tumors stage I-II, (2) recur greater than 6 months after their initial treatment, and (3) develop recurrences that are amenable to salvage surgery.