Diagnostic Delay in HPV-Related Oropharyngeal Squamous Cell Carcinoma

Introduction  Human papillomavirus-related (HPV + ) oropharyngeal squamous cell carcinoma (OPSCC) is increasing in incidence and presents diagnostic challenges given its unique clinical presentation. Objective  The purpose of the present study is to characterize the impact of the unique clinical presentation of HPV-related OPSCC on delays in diagnosis. Methods  Retrospective review of presenting symptoms and clinical characteristics of 284 patients with OPSCC treated from 2002-2014. Delay in diagnosis was defined as the presence of any of the following: multiple non-diagnostic fine needle aspirate (FNA) biopsies; two or more courses of antibiotic therapy; surgery with incorrect preoperative diagnosis; evaluation by an otolaryngologist without further workup; or surgery without definitive postoperative diagnosis. Results  p16+ tumors demonstrated a distinct clinical presentation that more commonly involved a neck mass (85.1% versus 57.3% of p16-; p  < 0.001) and less frequently included odynophagia (24.6% versus 51.7% of p16-; p  < 0.001). Patients who experienced diagnostic delay were more likely to have p16+ tumors (77.7% delayed versus 62.8% not delayed; p  = 0.006). p16+ primary tumors were more likely to be undetectable by physical examination of the head and neck including flexible laryngoscopy (19.0% versus 6.7% of p16-; p  = 0.007) and more frequently associated with nondiagnostic FNA biopsies of a cervical nodal mass (11.8% versus 3.4% of p16-, p  = 0.03). Conclusions  Compared with non-HPV related OPSCC, the unique clinical presentation and characteristics of HPV+ OPSCC are associated with an increased incidence of diagnostic delay. Targeted education of appropriate care providers may improve time to diagnosis and treatment.

Novel HPV Associated Oropharyngeal Squamous Cell Carcinoma Surveillance DNA Assay Cost Analysis

OBJECTIVES

We aim to propose a modified surveillance strategy using a novel blood assay that detects plasma circulating tumor-specific HPV DNA with reported 100% NPV and 94% PPV as the main method of detection to understand the cost implications of potentially avoiding routine imaging and surveillance visits at our institution.

METHODS

We performed a retrospective chart review focusing on recurrences in p16+ patients with OPSCC and defined two surveillance strategies: "Strategy A", follow-up visits with flexible laryngoscopy (FL) plus regular imaging studies; "Strategy B", follow-up visits with FL plus regular NavDx assays and imaging used at the discretion of the physician(s) in cases of high clinical suspicion.

RESULTS

Of the p16+ OPSCC patients (n = 214), 23 had confirmed recurrence (11%). Standard work-flow model determined 72 imaging studies and 2198 physical examinations with FL were needed to detect one recurrence. Potential individual patient cost reduction during surveillance was 42%.

CONCLUSION

Implementing NavDx for HPV + OPSCC surveillance would benefit patients by reducing costs and unnecessary diagnostic testing.

LEVEL OF EVIDENCE

Step/Level 3 Laryngoscope, 133:3006-3012, 2023.

Initial Report of a Randomized Trial Comparing Conventional vs. Novel Treatment Planning Technique to Ameliorate Immunosuppression from Lung SBRT

PURPOSE/OBJECTIVE(S)

SBRT is highly effective against early-stage non-small cell lung cancer. Radiation Therapy (RT) is known to modulate the immune system and contribute to the generation of anti-tumor T cells and stimulate T cell infiltration into tumors. However, this anti-tumor activity is offset by radiation-induced immunosuppression (RIIS) which results in lower tumor control and survival. Lymphocytes are highly radiosensitive and RIIS means destroying existing as well as newly created cytotoxic and helper T lymphocytes. We hypothesized that optimizing RT treatment planning by considering circulating blood and lymphatics as a critical Organ at Risk (OAR) may mitigate RIIS.

MATERIALS/METHODS

We conducted an IRB approved NCI funded clinical trial for 50 early-stage lung cancer patients treated with SBRT alone, from 2020 to 2023, to investigate the ability to reduce RIIS by reducing dose to circulating blood and lymphatics with the aid of a predictive algorithm. All SBRT plans adhered to treatment parameters from RTOG 0813 (central) or RTOG 0915 (peripheral). Patients were randomized to two arms: experimental optimization for RIIS (to reduce dose to blood and lymphatic rich organs) versus standard SBRT planning (without optimization for RIIS). Peripheral blood samples were collected at baseline, end of Tx, 4 weeks and 6 months post Tx. Patients with baseline absolute lymphocyte counts (ALC) less than 0.5x109 cells/L were ineligible for the trial. Data acquired for all blood cell types as well as lymphocyte sub populations CD3+, CD4+, CD8+, CD19+, CD56+. Two sample t-test was used to determine the statistical significance between the cohorts at the time points.

RESULTS

The standard arm had an ALC reduction of 28% at one week post Tx and a nadir at 4 weeks with a 34% reduction. Absolute percentage reductions in ALC from baseline in the optimized arm compared to the standard arm are: end of treatment point (13%, p = 0.03), 4 weeks (12%, p = 0.08), 6 months (15%, p = 0.1), and all three time points together 13% (p = 0.001). ALC recovery appears to be faster in the optimized arm. Radiation induced suppression of all blood cell types are also reduced in the optimized arm with respect to standard arm (relative percentages): ALC (34%), WBC (47%), RBC (46%), platelets (40%), monocytes (100%), and neutrophils (62%) at 4-week mark. Average percentage reductions on integral doses, and V5 (volume receiving a 5 Gy dose) of optimized compared to standard plans are: aorta: 26%, 41% heart: 8%, 33%, vena cava: 32%, 52%, T spine: 51%, 81%, lymph nodes: 35%, 57%, total lung- ITV: 1.6%, 1%, body: 10%, 14%.

CONCLUSION

For the first time, we have shown that it is possible to reduce RIIS in a statistically significant manner, compared to standard of care, via optimized RT planning using a predictive model. This has implications in increasing the efficacy of immunotherapy by preserving the existing tumor reactive T cells in the immune system to enhance anti-tumor activity, and in reducing hospitalizations and improving survival.

STAT RT: a prospective pilot clinical trial of Scan-Plan-QA-Treat stereotactic body radiation therapy for painful osseous metastases

BACKGROUND

Planning and treatment of bone metastases with palliative radiotherapy often requires 1-3 weeks, resulting in patient inconvenience and delayed palliation. We developed an expedited workflow that delivers palliative stereotactic body radiation therapy (SBRT) to painful bone metastases in which CT, planning, quality assurance (QA), and initial treatment are performed one day. This prospective pilot clinical trial evaluates the feasibility, safety, efficacy, and patient satisfaction of this workflow.

METHODS

Patients with 1-3 painful bone metastases were prospectively enrolled and treated with 2-5 fractions of 5-10 Gy per fraction. Bone pain, opioid use, patient satisfaction, performance status, and quality of life were evaluated prior to and at 1, 4, 8, 12, 26, and 52 weeks post treatment. Outcomes and treatment-related toxicity were analyzed.

RESULTS

Twenty-eight patients were enrolled and 37 metastases treated, receiving an average of 21.6 Gy in 3.1 fractions. Median time from CT simulation to 1st treatment was 6.6 hours. Average worst pain scores were significantly lower at all post-treatment time points with maximal response noted at 3 months. Opioid use was not significantly different from baseline at any follow up. Performance status was significantly increased only at week 12. Bone pain quality of life was significantly increased at all time points except at 52 weeks while general quality of life was significantly increased at only weeks 8 and 26. Ninety-two percent of patients reported being mostly or completely satisfied with the treatment results from week 8 until the end of follow-up. There was no grade 3 or higher toxicities.

CONCLUSIONS

Results demonstrate that treating bone metastases with palliative SBRT via a multi-fraction Scan-Plan-QA-Treat patient centric workflow is feasible and safe. Although performance status, general quality of life, and opioid use were not significantly altered, patient satisfaction was high with this same-day treatment workflow.

The Neddylation Inhibitor Pevonedistat (MLN4924) Suppresses and Radiosensitizes Head and Neck Squamous Carcinoma Cells and Tumors

The cullin RING E3 ubiquitin ligase 4 (CRL4) with its substrate receptor CDT2 (CRL4-CDT2) is emerging as a critical regulator of DNA replication through targeting CDT1, SET8, and p21 for ubiquitin-dependent proteolysis. The aberrant increased stability of these proteins in cells with inactivated CRL4-CDT2 results in DNA rereplication, which is deleterious to cells due to the accumulation of replication intermediates and stalled replication forks. Here, we demonstrate that CDT2 is overexpressed in head and neck squamous cell carcinoma (HNSCC), and its depletion by siRNA inhibits the proliferation of human papilloma virus-negative (HPV-ve) HNSCC cells primarily through the induction of rereplication. Treatment of HNSCC with the NEDD8-activating enzyme inhibitor pevonedistat (MLN4924), which inhibits all cullin-based ligases, induces significant rereplication and inhibits HNSCC cell proliferation in culture and HNSCC xenografts in mice. Pevonedistat additionally sensitizes HNSCC cells to ionizing radiation (IR) and enhances IR-induced suppression of xenografts in mice. Induction of rereplication via CDT2 depletion, or via the stabilization or activation of CDT1, also radiosensitizes HNSCC cells. Collectively, these results demonstrate that induction of rereplication represents a novel approach to treating radioresistant HNSCC tumors and suggest that pevonedistat may be considered as an adjuvant for IR-based treatments. Mol Cancer Ther; 17(2); 368-80. ©2017 AACRSee all articles in this MCT Focus section, "Developmental Therapeutics in Radiation Oncology."

Clinical outcomes of helical conformal versus nonconformal palliative radiation therapy for axial skeletal metastases

PURPOSE

Palliative radiation therapy (RT) for bone metastases has traditionally been delivered with conventional, nonconformal RT (NCRT). Conformal RT (CRT) is potentially more complex and expensive than NCRT, but may reduce normal tissue dose and subsequently toxicity. In this retrospective analysis, we compared CRT with NCRT to investigate the association between conformality and toxicity.

METHODS AND MATERIALS

A retrospective analysis of patients receiving palliative RT for axial skeletal bone metastases from 2012 to 2014 was conducted. Patient and treatment characteristics were obtained including dosimetric variables, acute toxicity, and subjective pain during treatment and in the acute posttreatment period (≤60 days after completion). Statistical analyses included t tests, χ² tests, and multivariate logistic regression.

RESULTS

A total of 179 patients and 254 bone metastases were identified (142 CRT, 112 NCRT). The CRT and NCRT groups were well matched for baseline characteristics (number of fractions, field size, treatment sites, and concurrent chemotherapy). In multivariate logistic regression models, technique (CRT vs NCRT) was not associated with development of acute toxicity. Regarding toxicity, Eastern Cooperative Oncology Group performance status and total dose were significantly associated with a higher rate of acute toxicity during RT (odds ratios, 0.649 and 1.129 and P = .027 and .044, respectively), and only a higher number of vertebral bodies in the treatment field was significantly associated with acute toxicity post-treatment (odds ratios, 1.219, P = .028). CRT was associated with improvement in bone pain during and posttreatment (P = .049 and .045, respectively).

CONCLUSIONS

Our results demonstrate no difference in acute toxicity following palliative RT with CRT compared with NCRT for painful bone metastases; however, treatment volume did predict for increased toxicity. Larger studies may further elucidate the value of CRT including the impact of dose escalation for bone metastases and differences in patient reported outcomes between RT techniques.

Early Palliative Care Reduces End-of-Life Intensive Care Unit (ICU) Use but Not ICU Course in Patients with Advanced Cancer

BACKGROUND

Early palliative care for advanced cancer patients improves quality of life and survival, but less is known about its effect on intensive care unit (ICU) use at the end of life. This analysis assessed the effect of a comprehensive early palliative care program on ICU use and other outcomes among patients with advanced cancer.

PATIENTS AND METHODS

A retrospective cohort of patients with advanced cancer enrolled in an early palliative care program (n = 275) was compared with a concurrent control group of patients receiving standard care (n = 195) during the same time period by using multivariable logistic regression analysis. The multidisciplinary outpatient palliative care program used early end-of-life care planning, weekly interdisciplinary meetings to discuss patient status, and patient-reported outcomes assessment integrated within the electronic health record.

RESULTS

Patients in the control group had statistically significantly higher likelihood of ICU admission at the end of life (odds ratios [ORs]: last 6 months, 3.07; last month, 3.59; terminal admission, 4.69), higher likelihood of death in the hospital (OR, 4.14) or ICU (OR, 5.57), and lower likelihood of hospice enrollment (OR, 0.13). Use of chemotherapy or radiation did not significantly differ between groups, nor did length of ICU stay, code status, ICU procedures (other than cardiopulmonary resuscitation), disposition location, and outcomes after ICU admission.

CONCLUSION

Early palliative care significantly reduced ICU use at the end of life but did not change ICU events. This study supports early initiation of palliative care for advanced cancer patients before hospitalizations and intensive care. The Oncologist 2017;22:318-323 IMPLICATIONS FOR PRACTICE: Palliative care has shown clear benefit in quality of life and survival in advanced cancer patients, but less is known about its effect on intensive care. This retrospective cohort study at a university hospital showed that in the last 6 months of life, palliative care significantly reduced intensive care unit (ICU) and hospital admissions, reduced deaths in the hospital, and increased hospice enrollment. It did not, however, change patients' experiences within the ICU, such as number of procedures, code status, length of stay, or disposition. The findings further support that palliative care exerts its benefit before, rather than during, the ICU setting.

How dose sparing of cardiac structures correlates with in-field heart volume and sternal displacement

Cardiac irradiation increases the risk of coronary artery disease in patients with left‐sided breast cancer. Techniques exist to reduce cardiac irradiation, but the optimum technique depends on individual patient anatomy and physiology. We investigated the correlation of delta heart volume in field (dHVIF) and sternal excursion with dose sparing in heart and left anterior descending artery (LAD) to develop quantitative predictive models for expected dose to heart and LAD. A treatment planning study was performed on 97 left‐breast cancer patients who underwent whole breast radiotherapy (prescription dose = 50 Gy) under deep inspiratory breath hold (DIBH). Two CT datasets, free breathing (FB) and DIBH, were utilized for treatment planning and for determination of the internal anatomy‐based DIBH amplitude. The mean heart and LAD dose were compared between FB and DIBH plans and dose to the heart and LAD as a function of dHVIF and sternal excursion were determined. The [Average (STD); Range] mean heart doses from free breathing and DIBH are [120.5(65.2); 28.9 ~ 393.8] cGy and [67.5(25.1); 19.7 ~ 145.6] cGy, respectively. The mean LAD doses from free breathing and DIBH are [571.0(582.2); 42.2 ~ 2332.2] cGy and [185.9(127.0); 41.2 ~ 898.4] cGy, respectively. The mean dose reductions with DIBH are [53.1(50.6); ‐15.4 ~ 295.1] cGy for the heart and [385.1(513.4); ‐0.6 ~ 2105.8] cGy for LAD. Percent mean dose reductions to the heart and LAD with DIBH are 44% (p < 0.0001) and 67% (p < 0.0001), respectively, compared to FB. The dHVIF mean dose reduction correlation is 8.1 cGy/cc for the heart and 81.6 cGy/cc for LAD (with linear trend and y intercept: 26.0 cGy for the heart, 109.1 cGy for LAD). DIBH amplitude using sternal position was [1.3(4.8); .38 ~2.5] cm. The DIBH amplitude mean dose reduction correlation is 14 cGy/cm for the heart and 212 cGy/cm for LAD (with linear trend with y intercept: 35.6 cGy for the heart, 102.4 cGy for LAD). The strong correlation of dose sparing to the heart and LAD with dHVIF and sternal excursion suggests that mean dose sparing to heart and LAD can be predicted with either dHVIF or sternal excursion equally well. The metrics proposed could be utilized to allow providers to determine the relative dosimetric benefits of different heart‐sparing techniques as early as time of consultation.

PACS number(s): 87.53.Tf

Longitudinal patterns of cancer patient reported outcomes in end of life care predict survival

PURPOSE

Patients with advanced cancer typically demonstrate sharp deterioration in physical function and psychological status during the last months of life. This study evaluates the relationship between survival in patients with advanced cancer and longitudinal assessment of anxiety, depression, fatigue, pain interference, and/or physical function using the US National Institute of Health Patient Reported Outcomes Information System.

METHODS

Mixed-effects models were used to evaluate patient-reported outcome trajectories over time among patients with advanced loco-regional or metastatic cancer receiving care in a hospital-based palliative care clinic. Cox regression analysis was used to assess the statistical significance of differences in the probability of survival associated with patient-reported outcome scores.

RESULTS

A total of 472 patients completed 1992 assessments during the 18-month study period. Longitudinal scores for fatigue, pain interference, and physical function demonstrated statistically significant non-linear trajectories. Scores for depression, fatigue, pain interference, and physical function were highly statistically significant predictors of survival (p < 0.01). Clinically meaningful differences in the probability of survival were demonstrated between patients with scores at the 25th vs. 75th percentiles, with absolute differences in survival at 6 and 12 months after assessment from 10 to 18 percentage points.

CONCLUSIONS

Patient-reported outcomes can be used to reliably estimate where patients are along the trajectory of deteriorating health status leading toward the end of life, and for identifying patients with declining symptoms in need of referral to palliative care or more aggressive symptom management.

Phantomless patient-specific TomoTherapy QA via delivery performance monitoring and a secondary Monte Carlo dose calculation

PURPOSE

To describe the validation and implementation of a novel quality assurance (QA) system for TomoTherapy using a Monte Carlo (MC)-based secondary dose calculation and CT detector-based multileaf collimator (MLC) leaf opening time measurement QA verification. This system is capable of detecting plan transfer and delivery errors and evaluating the dosimetric impact of those errors.

METHODS

The authors' QA process, MCLogQA, utilizes an independent pretreatment MC secondary dose calculation and postdelivery TomoTherapy exit detector-based MLC sinogram comparison and log file examination to confirm accurate dose calculation, accurate dose delivery, and to verify machine performance. MC radiation transport simulations are performed to estimate patient dose utilizing prestored treatment machine-specific phase-space information, the patient's planning CT, and MLC sinogram data. Sinogram data are generated from both the treatment planning system (MC_TPS) and from beam delivery log files (MC_Log). TomoTherapy treatment planning dose (DTPS) is compared with DMC_TPS and DMC_Log via dose-volume metrics and mean region of interest dose statistics. For validation, in-phantom ionization chamber dose measurements (DIC) for ten sample patient plans are compared with the computed values.

RESULTS

Dose comparisons to in-phantom ion chamber measurements validate the capability of the MCLogQA method to detect delivery errors. DMC_Log agreed with DIC within 1%, while DTPS values varied by 2%-5% compared to DIC. The authors demonstrated that TomoTherapy treatments can be vulnerable to MLC deviations and interfraction output variations during treatment delivery. Interfractional Linac output variations for each patient were approximately 2% and average output was 1%-1.5% below the gold standard. While average MLC leaf opening time error from patient to patient varied from -0.6% to 1.6%, the MLC leaf errors varied little between fractions for the same patient plan, excluding one patient.

CONCLUSIONS

MCLogQA is a new TomoTherapy QA process that validates the planned dose before delivery and analyzes the delivered dose using the treatment exit detector and log file data. The MCLogQA procedure is an effective and efficient alternative to traditional phantom-based TomoTherapy plan-specific QA because it allows for comprehensive 3D dose verification, accounts for tissue heterogeneity, uses patient CT density tables, reduces total QA time, and provides for a comprehensive QA methodology for each treatment fraction.

A Phase I/II adaptive design for heterogeneous groups with application to a stereotactic body radiation therapy trial

Dose-finding studies that aim to evaluate the safety of single agents are becoming less common, and advances in clinical research have complicated the paradigm of dose finding in oncology. A class of more complex problems, such as targeted agents, combination therapies and stratification of patients by clinical or genetic characteristics, has created the need to adapt early-phase trial design to the specific type of drug being investigated and the corresponding endpoints. In this article, we describe the implementation of an adaptive design based on a continual reassessment method for heterogeneous groups, modified to coincide with the objectives of a Phase I/II trial of stereotactic body radiation therapy in patients with painful osseous metastatic disease. Operating characteristics of the Institutional Review Board approved design are demonstrated under various possible true scenarios via simulation studies.

Impact and timing of palliative care referral

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Background: Recent studies suggest that early integration of palliative care services into the care of patients with advanced cancer can improve end of life care. Unfortunately, there are insufficient resources for all advanced cancer to see palliative care from time of diagnosis. This 2012 CMS innovation award is attempting to improve identification of cancer patients in need of palliative care. Methods: In Year 1 of this award, increased staffing was added to existing palliative care resources to improve access. Patients were referred at discretion of their oncologist. A control group consisting of patients with similar diagnoses not referred to palliative care was identified including those without any contact with palliative care, and those who only saw palliative care in the hospitalization prior to death. Data regarding hospitalization in the last month of life, and hospice utilization was obtained. Results: Median time between referral to palliative care clinic and death was 72.5 days (mean 112). See table below. Conclusions: These data suggest patients referred to palliative care clinic within 3 months of death had benefits similar referral at time of diagnosis. However, many patients were never referred or referred only at the very end of life. The next phases of this award will utilize patient-reported outcome data to better identify those who need palliative care. Although most palliative care services are hospital-based, in this study, in-patient consultation only was too late to provide much benefit for these patients. Re-focusing scarce palliative care resources to the out-patient setting may have greater impact on patient care. [Table: see text]

Photodynamic therapy provides local control of cholangiocarcinoma in patients awaiting liver transplantation

Many transplant centers use endoscopically directed brachytherapy to provide locoregional control in patients with otherwise incurable cholangiocarcinoma (CCA) who are awaiting liver transplantation (LT). The use of endoscopic retrograde cholangiopancreatography (ERCP)-directed photodynamic therapy (PDT) as an alternative to brachytherapy for providing locoregional control in this patient population has not been studied. The aim of this study was to report on our initial experience using ERCP-directed PDT to provide local control in patients with unresectable CCA who were awaiting LT. Patients with unresectable CCA who underwent protocol-driven neoadjuvant chemoradiation and ERCP-directed PDT with the intent of undergoing LT were reviewed. Four patients with confirmed or suspected CCA met the inclusion criteria for protocol LT. All four patients (100%) successfully underwent ERCP-directed PDT. All patients had chemoradiation dose delays, and two patients had recurrent cholangitis despite PDT. None of these patients had progressive locoregional disease or distant metastasis following PDT. All four patients (100%) underwent LT. Intention-to-treat disease-free survival was 75% at mean follow-up of 28.1 months. In summary, ERCP-directed PDT is a reasonably well tolerated and safe procedure that may have benefit by maintaining locoregional tumor control in patients with CCA who are awaiting LT.

Agonist-induced Ca2+ sensitization in smooth muscle: redundancy of Rho guanine nucleotide exchange factors (RhoGEFs) and response kinetics, a caged compound study

Many agonists, acting through G-protein-coupled receptors and Gα subunits of the heterotrimeric G-proteins, induce contraction of smooth muscle through an increase of [Ca(2+)]i as well as activation of the RhoA/RhoA-activated kinase pathway that amplifies the contractile force, a phenomenon known as Ca(2+) sensitization. Gα12/13 subunits are known to activate the regulator of G-protein signaling-like family of guanine nucleotide exchange factors (RhoGEFs), which includes PDZ-RhoGEF (PRG) and leukemia-associated RhoGEF (LARG). However, their contributions to Ca(2+)-sensitized force are not well understood. Using permeabilized blood vessels from PRG(-/-) mice and a new method to silence LARG in organ-cultured blood vessels, we show that both RhoGEFs are activated by the physiologically and pathophysiologically important thromboxane A2 and endothelin-1 receptors. The co-activation is the result of direct and independent activation of both RhoGEFs as well as their co-recruitment due to heterodimerization. The isolated recombinant C-terminal domain of PRG, which is responsible for heterodimerization with LARG, strongly inhibited Ca(2+)-sensitized force. We used photolysis of caged phenylephrine, caged guanosine 5'-O-(thiotriphosphate) (GTPγS) in solution, and caged GTPγS or caged GTP loaded on the RhoA·RhoGDI complex to show that the recruitment and activation of RhoGEFs is the cause of a significant time lag between the initial Ca(2+) transient and phasic force components and the onset of Ca(2+)-sensitized force.

Pilot Study of iPad Incorporation Into Graduate Medical Education

BACKGROUND

Increased documentation and charting requirements are challenging for residents, given duty hour limits. Use of mobile electronic devices may help residents complete these tasks efficiently.

OBJECTIVE

To collect initial data on usage rates, information technology (IT) support requirements, and resident use of iPads during training.

METHODS

In this pilot study, we provided 12 residents/fellows from various specialties at the University of Virginia with an iPad with IT support. The system used a virtual private network with access to the institution's electronic health record. Participants were allowed to develop their own methods and systems for personalized iPad use, and after 9 months they provided data on the utility of the iPad. Feedback from the IT team also was obtained.

RESULTS

Average iPad use was 2.1 h/d (range, 0.5-6 h/d). The average self-reported reduction in administrative work due to the iPad was 2.7 h/wk (range, 0-9 h/wk). A total of 75% (9 of 12) of the users would recommend universal adoption among residents and fellows. More than 90% (11 of 12) of users reported the iPad would improve communication for coordination of care. A total of 68% (8 of 12) of users reported that an iPad facilitated their activities as educators of medical students and junior residents. Residents cited slow data entry into the electronic health record and hospital areas lacking Wi-Fi connectivity as potential drawbacks to iPad use. The IT team reported minimal support time for device setup, maintenance, and upgrades, and limited security risks.

CONCLUSIONS

The iPad may contribute to increased clinical efficiency, reduced hours spent on administrative tasks, and enhanced educational opportunities for residents, with minimal IT support.

p16 not a prognostic marker for hypopharyngeal squamous cell carcinoma

OBJECTIVE

To investigate the prognostic significance of p16 in patients with hypopharyngeal squamous cell carcinoma (HPSCC) and to evaluate the relationship between p16 and human papillomavirus (HPV). Unlike in oropharyngeal SCC (OPSCC), the prognostic significance of p16 in HPSCC and its association with HPV is unclear.

DESIGN

Retrospective medical chart review.

SETTING

University tertiary referral center.

PATIENTS

A total of 27 patients with HPSCC treated with definitive radiation therapy between 2002 and 2011 whose tissue was available for immunohistochemical analysis.

INTERVENTIONS

Twenty-two patients were treated with chemoradiation, and 5 with radiation alone. All tumor biopsy specimens were analyzed for p16 and, when sufficient tissue was available, for HPV DNA.

MAIN OUTCOME MEASURES

Overall survival (OS), locoregional control (LRC), disease-free survival (DFS), and laryngoesophageal dysfunction-free survival (LEDFS) were analyzed according to p16 status.

RESULTS

Findings for p16 were positive in 9 tumors and negative in 18 tumors. Median follow-up was 29.3 months. There was no significant difference in OS, LRC, DFS, or LEDFS for patients with p16-positive vs p16-negative tumors. Only 1 of the 19 tumors tested for HPV was found to be HPV positive. When used as a test for HPV, p16 had a positive predictive value of 17%.

CONCLUSIONS

In contrast to OPSCC, p16 expression in patients with HPSCC had a low positive predictive value for HPV and did not predict improved OS, LRC, DFS, or LEDFS. Thus, for HPSCC, p16 is not a prognostic biomarker. Caution must be taken when extrapolating the prognostic significance of p16 in patients with OPSCC to patients with head and neck SCC of other subsites.

Computed tomography-based anatomic assessment overestimates local tumor recurrence in patients with mass-like consolidation after stereotactic body radiotherapy for early-stage non-small cell lung cancer

PURPOSE

To investigate pulmonary radiologic changes after lung stereotactic body radiotherapy (SBRT), to distinguish between mass-like fibrosis and tumor recurrence.

METHODS AND MATERIALS

Eighty consecutive patients treated with 3- to 5-fraction SBRT for early-stage peripheral non-small cell lung cancer with a minimum follow-up of 12 months were reviewed. The mean biologic equivalent dose received was 150 Gy (range, 78-180 Gy). Patients were followed with serial CT imaging every 3 months. The CT appearance of consolidation was defined as diffuse or mass-like. Progressive disease on CT was defined according to Response Evaluation Criteria in Solid Tumors 1.1. Positron emission tomography (PET) CT was used as an adjunct test. Tumor recurrence was defined as a standardized uptake value equal to or greater than the pretreatment value. Biopsy was used to further assess consolidation in select patients.

RESULTS

Median follow-up was 24 months (range, 12.0-36.0 months). Abnormal mass-like consolidation was identified in 44 patients (55%), whereas diffuse consolidation was identified in 12 patients (15%), at a median time from end of treatment of 10.3 months and 11.5 months, respectively. Tumor recurrence was found in 35 of 44 patients with mass-like consolidation using CT alone. Combined with PET, 10 of the 44 patients had tumor recurrence. Tumor size (hazard ratio 1.12, P=.05) and time to consolidation (hazard ratio 0.622, P=.03) were predictors for tumor recurrence. Three consecutive increases in volume and increasing volume at 12 months after treatment in mass-like consolidation were highly specific for tumor recurrence (100% and 80%, respectively). Patients with diffuse consolidation were more likely to develop grade ≥ 2 pneumonitis (odds ratio 26.5, P=.02) than those with mass-like consolidation (odds ratio 0.42, P=.07).

CONCLUSION

Incorporating the kinetics of mass-like consolidation and PET to the current criteria for evaluating posttreatment response will increase the likelihood of correctly identifying patients with progressive disease after lung SBRT.

p16, Cyclin D1, and HIF-1α Predict Outcomes of Patients with Oropharyngeal Squamous Cell Carcinoma Treated with Definitive Intensity-Modulated Radiation Therapy

We evaluated a panel of 8 immunohistochemical biomarkers as predictors of clinical response to definitive intensity-modulated radiotherapy in patients with oropharyngeal squamous cell carcinoma (OPSCC). 106 patients with OPSCC were treated to a total dose of 66-70 Gy and retrospectively analyzed for locoregional control (LRC), disease-free survival (DFS), and overall survival (OS). All tumors had p16 immunohistochemical staining, and 101 tumors also had epidermal growth factor receptor (EGFR) staining. 53% of the patients had sufficient archived pathologic specimens for incorporation into a tissue microarray for immunohistochemical analysis for cyclophilin B, cyclin D1, p21, hypoxia-inducible factor-1α (HIF-1α), carbonic anhydrase, and major vault protein. Median followup was 27.2 months. 66% of the tumors were p16 positive, and 34% were p16 negative. On univariate analysis, the following correlations were statistically significant: p16 positive staining with higher LRC (P = 0.005) and longer DFS (P < 0.001); cyclin D1 positive staining with lower LRC (P = 0.033) and shorter DFS (P = 0.002); HIF-1α positive staining with shorter DFS (P = 0.039). On multivariate analysis, p16 was the only significant independent predictor of DFS (P = 0.023). After immunohistochemical examination of a panel of 8 biomarkers, our study could only verify p16 as an independent prognostic factor in OPSCC.

Helical tomotherapy simultaneous integrated boost provides a dosimetric advantage in the treatment of primary intracranial tumors

OBJECTIVE

The research quantitatively evaluates the dosimetric advantage of a helical tomotherapy (HT) intensity-modulated radiation therapy simultaneous integrated boost (SIB) compared to a conventional HT sequential (SEQ) boost for primary intracranial tumors.

METHODS

Hypothetical lesions (planning target volumes or PTVs) were contoured within computed tomography scans from normal controls. A dose of 50 Gy was prescribed to the larger PTV1, while the boost PTV2 received a total of 60 Gy. HT SEQ and HT SIB plans were generated and compared. We evaluated the mean brain dose, the volume of normal brain receiving 45 Gy (V45), the volume of normal brain receiving 5 Gy (V5), and the integral dose. In addition, patients who were treated with the HT SEQ technique were replanned with the HT SIB technique and compared.

RESULTS

The average reduction in mean brain dose with the HT SIB plan compared to the composite HT SEQ plan was 11·0% [standard error (SE): 0·5]. The reductions in brains V45 and V5 were 43·7% (SE: 2·3) and 3·9% (SE: 0·6), respectively. The reduction in the integral dose was 11·0% (SE: 0·5). When comparing the SIB plan to the first 50 Gy only of the SEQ plan, there was only a 2·5% increase in the mean brain dose and a 2·9% increase in brain V45. This increase was dependent on the relative volumes of PTV2 and PTV1. These results were confirmed for the patient plans compared.

CONCLUSIONS

Treating primary brain tumors with the HT SIB technique provides significant sparing of normal brain parenchyma compared to a conventional HT SEQ boost.

Quantifying the reproducibility of heart position during treatment and corresponding delivered heart dose in voluntary deep inhalation breath hold for left breast cancer patients treated with external beam radiotherapy

PURPOSE

Voluntary deep inhalation breath hold (VDIBH) reduces heart dose during left breast irradiation. We present results of the first study performed to quantify reproducibility of breath hold using bony anatomy, heart position, and heart dose for VDIBH patients at treatment table.

METHODS AND MATERIALS

Data from 10 left breast cancer patients undergoing VDIBH whole-breast irradiation were analyzed. Two computed tomography (CT) scans, free breathing (FB) and VDIBH, were acquired to compare dose to critical structures. Pretreatment weekly kV orthogonal images and tangential ports were acquired. The displacement difference from spinal cord to sternum across the isocenter between coregistered planning Digitally Reconstructed Radiographs (DRRs) and kV imaging of bony thorax is a measure of breath hold reproducibility. The difference between bony coregistration and heart coregistration was the measured heart shift if the patient is aligned to bony anatomy.

RESULTS

Percentage of dose reductions from FB to VDIBH: mean heart dose (48%, SD 19%, p = 0.002), mean LAD dose (43%, SD 19%, p = 0.008), and maximum left anterior descending (LAD) dose (60%, SD 22%, p = 0.008). Average breath hold reproducibility using bony anatomy across the isocenter along the anteroposterior (AP) plane from planning to treatment is 1 (range, 0-3; SD, 1) mm. Average heart shifts with respect to bony anatomy between different breath holds are 2 ± 3 mm inferior, 1 ± 2 mm right, and 1 ± 3 mm posterior. Percentage dose changes from planning to delivery: mean heart dose (7%, SD 6%); mean LAD dose, ((9%, SD 7%)S, and maximum LAD dose, (11%, SD 11%) SD 11%, p = 0.008).

CONCLUSION

We observed excellent three-dimensional bony registration between planning and pretreatment imaging. Reduced delivered dose to heart and LAD is maintained throughout VDIBH treatment.

Helical tomotherapy planning for lung cancer based on ventilation magnetic resonance imaging

To investigate the feasibility of lung ventilation-based treatment planning, computed tomography and hyperpolarized (HP) helium-3 (He-3) magnetic resonance imaging (MRI) ventilation images of 6 subjects were coregistered for intensity-modulated radiation therapy planning in Tomotherapy. Highly-functional lungs (HFL) and less-functional lungs (LFL) were contoured based on their ventilation image intensities, and a cylindrical planning-target-volume was simulated at locations adjacent to both HFL and LFL. Annals of an anatomy-based plan (Plan 1) and a ventilation-based plan (Plan 2) were generated. The following dosimetric parameters were determined and compared between the 2 plans: percentage of total/HFL volume receiving ≥20 Gy, 15 Gy, 10 Gy, and 5 Gy (TLV(20), HFLV(20), TLV(15), HFLV(15), TLV(10), HFLV(10), TLV(5), HFLV(5)), mean total/HFL dose (MTLD/HFLD), maximum doses to all organs at risk (OARs), and target dose conformality. Compared with Plan 1, Plan 2 reduced mean HFLD (mean reduction, 0.8 Gy), MTLD (mean reduction, 0.6 Gy), HFLV(20) (mean reduction, 1.9%), TLV(20) (mean reduction, 1.5%), TLV(15) (mean reduction, 1.7%), and TLV(10) (mean reduction, 2.1%). P-values of the above comparisons are less than 0.05 using the Wilcoxon signed rank test. For HFLV(15), HFLV(10), TLV(5), and HTLV(5), Plan 2 resulted in lower values than plan 1 but the differences are not significant (P-value range, 0.063-0.219). Plan 2 did not significantly change maximum doses to OARs (P-value range, 0.063-0.563) and target conformality (P = 1.000). HP He-3 MRI of patients with lung disease shows a highly heterogeneous ventilation capacity that can be utilized for functional treatment planning. Moderate but statistically significant improvements in sparing functional lungs were achieved using helical tomotherapy plans.

Primary pericardial malignant mesothelioma and response to radiation therapy

We report a case of a primary pericardial malignant mesothelioma. A 59-year-old male presented with episodic chest pain and dyspnea on exertion. Cardiac magnetic resonance imaging revealed a large mass in the pericardium attached to the right ventricle. Partial resection of the mass was undertaken revealing malignant mesothelioma, byphasic type. The patient was treated with chemotherapy intermittently over a period of 3 years, but his disease continued to progress. The patient was then treated with definitive radiation therapy to 64 Gy to the primary tumor using a six field 3D conformal technique. The patient remains free of progressive disease 86 months from the time of diagnosis and 50 months from the completion of his radiotherapy.

Size matters: a comparison of T1 and T2 peripheral non-small-cell lung cancers treated with stereotactic body radiation therapy (SBRT)

OBJECTIVE

The purpose of this study was to compare the outcomes and local control rates of patients with peripheral T1 and T2 non-small-cell lung cancer treated with stereotactic body radiation therapy.

METHODS

The records of 40 consecutive patients treated with 3- or 5-fraction lung stereotactic body radiation therapy for peripheral, clinical stage I non-small-cell lung cancer were reviewed. Stereotactic body radiation therapy was delivered at a median dose of 60 Gy. Doses to organs at risk were limited based on the Radiation Therapy Oncology Group 0236 treatment protocol. Patients were staged clinically. Median follow was 12.5 months.

RESULTS

Twenty-seven (67%) patients and 13 (33%) patients had T1 and T2 tumors, respectively. Thirty-seven (94%) patients were medically inoperable. Nine (23%) patients had chest wall pain after stereotactic body radiation therapy. Symptomatic pneumonitis developed in 4 (10%) patients. Increasing tumor size correlated with worse local control and overall survival. The median recurrence-free survival for T1 and T2 tumors was 30.6 months (95% confidence interval [CI], 26.9-34.2) and 20.5 months (95% CI, 14.3-26.5), respectively (P = .038). Local control at 2 years was 90% and 70% in T1 and T2 tumors, respectively (P = .03). The median survival for T1 and T2 tumors was 20 months (95% CI, 20.1-31.6) and 16.7 months (95% CI, 10.8-21.2), respectively (P = .073).

CONCLUSIONS

Stereotactic body radiation therapy for T2 non-small-cell lung cancer has a higher local recurrence rate and trended toward a worse survival than did T1 lesions. Tumor size is an important predictor of response to stereotactic body radiation therapy and should be considered in treatment planning.

Primary nasopharyngeal interdigitating dendritic cell tumor presentation and response to radiation therapy

We report the case of a primary nasopharyngeal interdigitating dendritic cell tumor (IDDCT). A 25-year old male presented with bilateral decreased hearing, double vision, and ataxia. Flexible nasopharyngoscopy reviewed a large mass obstructing and filling the entire nasopharynx. MRI and PET-CT confirmed the presence of the primary tumor and demonstrated bilateral cervical lymphadenopathy. Biopsy of the nasopharynx revealed a hematolymphoid neoplasm with dendritic cell differentiation, most consistent with an IDDCT. The lesion was unresectable. The patient was treated with definitive radiotherapy to 66 Gy to the primary tumor and 50 Gy to the bilateral cervical lymphatics using an IMRT technique. A complete response was achieved and the patient remains disease free at the primary site 23 months after completion of radiotherapy.

Survey on human papillomavirus/p16 screening use in oropharyngeal carcinoma patients in the United States

BACKGROUND

Patients with human papillomavirus (HPV)-positive oropharyngeal carcinoma (OC) have better prognosis than patients with HPV-negative OC. The objective of the current study was to assess how different practices across the United States treat patients with OC with respect to screening for HPV DNA or p16.

METHODS

Five hundred forty-two randomly selected radiation oncologists were sent an 11-question survey by email regarding the use of HPV/p16 screening in OC. The questionnaire addressed demographics of the practice, intensity-modulated radiotherapy (IMRT) use, screening practices for HPV DNA or p16, which year this began, the use of HPV or p16 data to direct patient care, and future plans for its use if it had not already been instituted.

RESULTS

One hundred ninety-two responses (39.6%) were received. Thirty-five percent of respondents (67 of 188) reported screening for HPV DNA routinely, whereas 4.8% of respondents (9 of 188) reported screening for p16. Of the physicians who did not use screening techniques, 37.2% (44 of 118 respondents) reported future plans to institute these screening techniques, 20% (9 of 45 respondents) stated plans to institute these techniques in the next 6 months, 55.5% (25 of 45 respondents) stated plans to institute these techniques within 6 months to 1 year, and 22.2% (10 of 45 respondents) stated plans to institute these techniques within 1 to 2 years. Academic physicians were more likely to use screening techniques (62.7%; P < .001) compared with private practitioners (31.4%). Only 12.4% of respondents reported using HPV or p16 data to direct care.

CONCLUSIONS

Approximately 40.4% of radiation oncology practices that responded to a survey in the United States screened for HPV DNA or p16 in OC, whereas only 12.4% used it to further direct care. This number appears to be growing rapidly. Clinical trials to further elucidate how HPV or p16 status should direct care in OC are warranted.

Predicting residual neck disease in patients with oropharyngeal squamous cell carcinoma treated with radiation therapy: utility of p16 status

OBJECTIVE

To identify factors that predict complete response of cervical nodal disease to radiation therapy (RT) in patients with oropharyngeal squamous cell carcinoma (OP-SCCA).

DESIGN

Histologic analysis of prospectively collected specimens and retrospective medical chart review.

SETTING

Tertiary referral center.

SUBJECTS

Sixty-nine patients with OP-SCCA treated from January 1, 2002, through June 1, 2008.

INTERVENTION

Definitive RT, with or without chemotherapy and with or without neck dissection (ND).

MAIN OUTCOME MEASURE

Presence of a viable tumor in post-RT ND specimen.

RESULTS

Tissue specimens from 69 patients with OP-SCCA treated primarily with RT, with or without chemotherapy, were evaluated. Of these, 47 (68.1%) were strongly and diffusely positive for p16 expression by immunohistochemical analysis, signifying human papillomavirus positivity. Patients with p16-positive and p16-negative tumors (hereinafter, p16+ and p16-, respectively) had similarly sized primary tumors on presentation, but p16+ primary tumors were associated with more advanced neck disease (nodal stages N2c-N3; 31.9% vs 4.5% for p16- tumors) and more contralateral nodes (27.7% vs 4.5% for p16- tumors). Forty-seven patients (59.0%) underwent planned posttreatment ND (a total of 55 NDs). The NDs performed for p16- tumors were significantly more likely to have viable tumor in the specimen (50.0% vs 18.0% for p16+ tumors; P = .02). In addition, p16+ necks with residual viable cancer were characterized by incomplete response on post-RT imaging, tobacco and alcohol use, and extracapsular spread on pretreatment imaging.

CONCLUSIONS

In conjunction with other clinical parameters, p16 status can help predict the need for post-RT ND in patients with OP-SCCA. Although close observation may be warranted in selected patients with p16+ tumors, patients with p16- tumors are at much higher risk for residual neck disease, even when initial nodal disease is less advanced.

Tracking brain motion during the cardiac cycle using spiral cine-DENSE MRI

Cardiac-synchronized brain motion is well documented, but the accurate measurement of such motion on the pixel-by-pixel basis has been hampered by the lack of proper imaging technique. In this article, the authors present the implementation of an autotracking spiral cine displacement-encoded stimulation echo (DENSE) magnetic resonance imaging (MRI) technique for the measurement of pulsatile brain motion during the cardiac cycle. Displacement-encoded dynamic MR images of three healthy volunteers were acquired throughout the cardiac cycle using the spiral cine-DENSE pulse sequence gated to the R wave of an electrocardiogram. Pixelwise Lagrangian displacement maps were computed, and 2D displacement as a function of time was determined for selected regions of interests. Different intracranial structures exhibited characteristic motion amplitude, direction, and pattern throughout the cardiac cycle. Time-resolved displacement curves revealed the pathway of pulsatile motion from brain stem to peripheral brain lobes. These preliminary results demonstrated that the spiral cine-DENSE MRI technique can be used to measure cardiac-synchronized pulsatile brain motion on the pixel-by-pixel basis with high temporal/spatial resolution and sensitivity.

Dynamic MRI of grid-tagged hyperpolarized helium-3 for the assessment of lung motion during breathing

PURPOSE

To develop a dynamic magnetic resonance imaging (MRI) tagging technique using hyperpolarized helium-3 (HP He-3) to track lung motion.

METHODS AND MATERIALS

An accelerated non-Cartesian k-space trajectory was used to gain acquisition speed, at the cost of introducing image artifacts, providing a viable strategy for obtaining whole-lung coverage with adequate temporal resolution. Multiple-slice two-dimensional dynamic images of the lung were obtained in three healthy subjects after inhaling He-3 gas polarized to 35%-40%. Displacement, strain, and ventilation maps were computed from the observed motion of the grid peaks.

RESULTS

Both temporal and spatial variations of pulmonary mechanics were observed in normal subjects, including shear motion between different lobes of the same lung.

CONCLUSION

These initial results suggest that dynamic imaging of grid-tagged hyperpolarized magnetization may potentially be a powerful tool for observing and quantifying pulmonary biomechanics on a regional basis and for assessing, validating, and improving lung deformable image registration algorithms.

Utilization of tomotherapy-based topotherapy for emerging breast radiation techniques: boost integration and accelerated partial breast irradiation

Abstract #5148

Background: Helical Tomotherapy-based intensity modulated radiation therapy (IMRT) can be delivered using fixed gantry angles, known as Topotherapy, with daily image guidance. With the advent of accelerated or hypofractionated treatment schemes to shorten courses of radiation, conformality and accuracy is imperative for breast radiotherapy techniques since high doses of targeted radiation are used. The purpose of this study was to characterize the dosimetry of Topotherapy for delivery of Accelerated Partial Breast Irradiation (APBI) and hypofractionated Simultaneous Integrated Boost (SIB) breast irradiation in comparison with conventional techniques.&#x2028; Materials and Methods: Ten patients with early stage left sided breast cancer were evaluated for this study using Topotherapy planning. The planning target volume (PTV) was contoured as the lumpectomy cavity with a 1.5cm margin, and the breast was defined by the tissue encompassed by tangent fields minus the PTV and 5mm of skin. To evaluate SIB, nine patients were comparatively planned using a standard sequential treatment of 50Gy tangents to the whole breast with a 10Gy electron boost in 30 fractions versus Topotherapy integrated boost with the same cumulative dose in 25 fractions versus hypofractionated Topotherapy with 42.4Gy to the breast and 51.2Gy to the PTV in 16 fractions. For evaluation of APBI, 3cm hypothetical lumpectomy cavities were contoured in the four breast quadrants of a single patient, with a similar 1.5cm expansion and breast volume. Plans to deliver 38.5Gy in 10 fractions were generated for each lesion using Topotherapy and compared to 3-dimensional conformal radiation therapy (3DCRT) and IMRT using the dosimetric guidelines from the National Surgical Adjuvant Breast and Bowel Project B-39/Radiation Therapy Oncology Group 0413 protocol.&#x2028; Results: Target coverage and dose to heart and lung were clinically equivalent when comparing Topotherapy APBI and SIB to conventional techniques. For ABPI, the Topotherapy conformality index was superior to 3DCRT for all breast quadrants, but inferior to IMRT for lesions located in the medial quadrants of the breast. For SIB, Topotherapy provided an improvement in conformality over conventional sequential techniques, however there was no intensity modulated comparison. Equivalent target uniformity was observed in all APBI techniques however for SIB, Topotherapy provided a superior uniformity index for the whole breast target.&#x2028; Discussion: Topotherapy is capable of delivering clinically acceptable dosimetry for accelerated or hypofractionated breast radiation without compromising dose to structures at risk. This treatment modality will be utilized in the near future pending FDA approval.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 5148.

Reproducibility of interfraction lung motion probability distribution function using dynamic MRI: statistical analysis

PURPOSE

To investigate the statistical reproducibility of craniocaudal probability distribution function (PDF) of interfraction lung motion using dynamic magnetic resonance imaging.

METHODS AND MATERIALS

A total of 17 subjects, 9 healthy volunteers and 8 lung tumor patients, underwent two to three continuous 300-s magnetic resonance imaging scans in the sagittal plane, repeated 2 weeks apart. Three pulmonary vessels from different lung regions (upper, middle, and lower) in the healthy subjects and lung tumor patients were selected for tracking, and the displacement PDF reproducibility was evaluated as a function of scan time and frame rate.

RESULTS

For both healthy subjects and patients, the PDF reproducibility improved with increased scan time and converged to an equilibrium state during the 300-s scan. The PDF reproducibility at 300 s (mean, 0.86; range, 0.70-0.96) were significantly (p < 0.001) increased compared with those at 5 s (mean, 0.65; range, 0.25-0.79). PDF reproducibility showed less sensitivity to imaging frame rates that were >2 frames/s.

CONCLUSION

A statistically significant improvement in PDF reproducibility was observed with a prolonged scan time among the 17 participants. The confirmation of PDF reproducibility over times much shorter than stereotactic body radiotherapy delivery duration is a vital part of the initial validation process of probability-based treatment planning for stereotactic body radiotherapy for lung cancer.

Evaluation of coplanar partial left breast irradiation using tomotherapy-based topotherapy

PURPOSE

To investigate the use of topotherapy for accelerated partial breast irradiation through field-design optimization and dosimetric comparison to linear accelerator-based three-dimensional conformal radiotherapy (3D-CRT) and intensity-modulated radiation therapy (IMRT).

METHODS AND MATERIALS

Hypothetical 3-cm lumpectomy sites were contoured in each quadrant of a left breast by using dosimetric guidelines from the National Surgical Adjuvant Breast and Bowel Project B-39/Radiation Therapy Oncology Group 0413 protocol. Coplanar intensity-modulated topotherapy treatment plans were optimized by using two-, three-, four-, five-, and seven-field arrangements for delivery by the tomotherapy unit with fixed gantry angles. Optimized noncoplanar five-field 3D-CRT and IMRT were compared with corresponding topotherapy plans.

RESULTS

On average, 99.5% +/- 0.5% of the target received 100% of the prescribed dose for all topotherapy plans. Average equivalent uniform doses ranged from 1.20-2.06, 0.79-1.76, and 0.10-0.29 Gy for heart, ipsilateral lung, and contralateral lung, respectively. Average volume of normal breast exceeding 90% of the prescription and average area of skin exceeding 35 Gy were lowest for five-field plans. Average uniformity indexes for five-field plans using 3D-CRT, IMRT, and topotherapy were 1.047, 1.050, and 1.040, respectively. Dose-volume histograms and calculated equivalent uniform doses of all three techniques illustrate clinically equivalent doses to ipsilateral breast, lung, and heart.

CONCLUSIONS

This dosimetric evaluation for a single patient shows that coplanar partial breast topotherapy provides good target coverage with exceptionally low dose to organs at risk. Use of more than five fields provided no additional dosimetric advantage. A comparison of five-field topotherapy to 3D-CRT and IMRT for accelerated partial breast irradiation illustrates equivalent target conformality and uniformity.

Molecular architectures for trimetallic d/f/d complexes: magnetic studies of a LnCu2 core

Five new trinuclear Cu-Ln-Cu cluster complexes have been prepared by a one-pot reaction using H3bcn (tris- N,N',N''-(2-hydroxybenzyl)-1,4,7-triazacyclononane) and Ln = La(III), Nd(III), Gd(III), Dy(III), and Yb(III) where the d- and f-block metal ions are in close proximity desirable for magnetic studies. The [LnCu2(bcn)2]ClO4.nH2O complexes possess the same stoichiometry as the previously reported [LnNi2(bcn)2]ClO4.nH2O and [LnZn2(bcn)2]ClO4.nH2O systems. Additionally, the solid state structures of the LnCu2 complexes appear to be isostructural to the LnNi2 and LnZn2 species as determined by their nearly superimposable IR spectra. The similarities in the structures of the [LnTM2(bcn)2]ClO4.nH2O series, where TM = Zn(II), Ni(II), and Cu(II), allow for direct comparison of their magnetic exchange. An empirical approach, removing first-order anisotropic contributions determined from the analogous [LnZn2(bcn)2]ClO4.nH2O was used to study the d/f/d spin interactions in the [LnCu2(bcn)2]ClO4.nH2O complexes. A ferromagnetic exchange was determined where Ln = Gd(III), Dy(III), or Yb(III) and an antiferromagnetic exchange for Ln = Nd(III), identical to the magnetic exchange observed for the [LnNi2(bcn)2]ClO4.nH2O complexes. An exchange integral of 3.67 cm(-1) for the trimetallic [GdCu2(bcn)2]ClO4.3H2O species was determined using a modified spin Hamiltonian. The [Cu(Hbcn)] and the [Cu3(Hbcn)2](ClO4)2 building blocks of the larger coaggregated d/f/d species were also synthesized, and their structures are reported.

Estimation of Error in Maximal Intensity Projection-Based Internal Target Volume of Lung Tumors: A Simulation and Comparison Study Using Dynamic Magnetic Resonance Imaging

PURPOSE

To evaluate the error in four-dimensional computed tomography (4D-CT) maximal intensity projection (MIP)-based lung tumor internal target volume determination using a simulation method based on dynamic magnetic resonance imaging (dMRI).

METHODS AND MATERIALS

Eight healthy volunteers and six lung tumor patients underwent a 5-min MRI scan in the sagittal plane to acquire dynamic images of lung motion. A MATLAB program was written to generate re-sorted dMRI using 4D-CT acquisition methods (RedCAM) by segmenting and rebinning the MRI scans. The maximal intensity projection images were generated from RedCAM and dMRI, and the errors in the MIP-based internal target area (ITA) from RedCAM (epsilon), compared with those from dMRI, were determined and correlated with the subjects' respiratory variability (nu).

RESULTS

Maximal intensity projection-based ITAs from RedCAM were comparatively smaller than those from dMRI in both phantom studies (epsilon = -21.64% +/- 8.23%) and lung tumor patient studies (epsilon = -20.31% +/- 11.36%). The errors in MIP-based ITA from RedCAM correlated linearly (epsilon = -5.13nu - 6.71, r(2) = 0.76) with the subjects' respiratory variability.

CONCLUSIONS

Because of the low temporal resolution and retrospective re-sorting, 4D-CT might not accurately depict the excursion of a moving tumor. Using a 4D-CT MIP image to define the internal target volume might therefore cause underdosing and an increased risk of subsequent treatment failure. Patient-specific respiratory variability might also be a useful predictor of the 4D-CT-induced error in MIP-based internal target volume determination.

Cisplatin and fluorouracil alone or with docetaxel in head and neck cancer

BACKGROUND

A randomized phase 3 trial of the treatment of squamous-cell carcinoma of the head and neck compared induction chemotherapy with docetaxel plus cisplatin and fluorouracil (TPF) with cisplatin and fluorouracil (PF), followed by chemoradiotherapy.

METHODS

We randomly assigned 501 patients (all of whom had stage III or IV disease with no distant metastases and tumors considered to be unresectable or were candidates for organ preservation) to receive either TPF or PF induction chemotherapy, followed by chemoradiotherapy with weekly carboplatin therapy and radiotherapy for 5 days per week. The primary end point was overall survival.

RESULTS

With a minimum of 2 years of follow-up (> or =3 years for 69% of patients), significantly more patients survived in the TPF group than in the PF group (hazard ratio for death, 0.70; P=0.006). Estimates of overall survival at 3 years were 62% in the TPF group and 48% in the PF group; the median overall survival was 71 months and 30 months, respectively (P=0.006). There was better locoregional control in the TPF group than in the PF group (P=0.04), but the incidence of distant metastases in the two groups did not differ significantly (P=0.14). Rates of neutropenia and febrile neutropenia were higher in the TPF group; chemotherapy was more frequently delayed because of hematologic adverse events in the PF group.

CONCLUSIONS

Patients with squamous-cell carcinoma of the head and neck who received docetaxel plus cisplatin and fluorouracil induction chemotherapy plus chemoradiotherapy had a significantly longer survival than did patients who received cisplatin and fluorouracil induction chemotherapy plus chemoradiotherapy. (ClinicalTrials.gov number, NCT00273546 [ClinicalTrials.gov].).

MR grid-tagging using hyperpolarized helium-3 for regional quantitative assessment of pulmonary biomechanics and ventilation

A new technique is demonstrated in six healthy human subjects that combines grid-tagging and hyperpolarized helium-3 MRI to assess regional lung biomechanical function and quantitative ventilation. 2D grid-tagging, achieved by applying sinc-modulated RF-pulse trains along the frequency- and phase-encoding directions, was followed by a multislice fast low-angle shot (FLASH)-based acquisition at inspiration and expiration. The displacement vectors, first and second principal strains, and quantitative ventilation were computed, and mean values were calculated for the upper, middle, and lower lung regions. Displacements in the lower region were significantly greater than those in either the middle or upper region (P < 0.005), while there were no significant differences between the three regions for the two principal strains and quantitative ventilation (P = 0.11-0.92). Variations in principal strains and ventilation were greater between subjects than between lung zones within individual subjects. This technique has the potential to provide insight into regional biomechanical alterations of lung function in a variety of lung diseases.

Evaluation of thoracic spinal cord motion using dynamic MRI

The aim of study was to assess the thoracic spinal cord motion during normal breathing using dynamic magnetic resonance imaging (dMRI). We found that the mean motion range at different thoracic levels is typically within 0.5mm. The good stability makes this an excellent position for stereotactic radiotherapy (SBRT).