Medicine, Dentistry & Health Sciences Collected Works - Research Publications

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    Prognostic significance of pre-treatment neutrophil-to-lymphocyte ratio (NLR) in patients with oropharyngeal cancer treated with radiotherapy
    Ng, SP ; Bahig, H ; Jethanandani, A ; Sturgis, EM ; Johnson, FM ; Elgohari, B ; Gunn, GB ; Ferrarotto, R ; Phan, J ; Rosenthal, DI ; Frank, SJ ; Fuller, CD ; Garden, AS (SPRINGERNATURE, 2021-02-02)
    BACKGROUND: This study aimed to evaluate the prognostic value of pre-treatment NLR in patients with oropharyngeal cancer. METHODS: Patients who completed definitive radiotherapy (RT) for oropharyngeal cancer and had blood counts taken pre-RT from 2002 to 2013 were included. NLR was calculated as total neutrophil/lymphocytes. Survival rates were estimated using the Kaplan-Meier method. Univariable and multivariable analyses were conducted with linear and Cox regression methods. NLR was analysed posteriori and dichotomised on the discovered median. RESULTS: Eight hundred and forty-eight patients were analysed. The median pre-RT NLR was 3. Patients with NLR of <3 had improved overall survival (OS) than those with NLR ≥ 3 (5-year OS 85 vs 74%, p < 0.0001). OS differences remained significant when stratified according to HPV status (HPV-positive p = 0.011; HPV-negative p = 0.003). Freedom from any recurrence (FFR), locoregional control (LRC) and freedom of distant recurrence (FDR) were better in those with NLR < 3. The negative impact of elevated pre-RT NLR on OS (HR = 1.64, p = 0.001), FFR (HR = 1.6, p = 0.006) and LRC (HR = 1.8, p = 0.005) remained significant on multivariable analysis. CONCLUSIONS: Pre-RT NLR is an independent prognostic factor in patients with oropharyngeal cancer regardless of HPV status. Patients with lower NLR had more favourable OS and disease control.
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    A prospective evaluation of health-related quality of life after skull base re-irradiation
    Bahig, H ; Ng, SP ; Pollard, C ; Nguyen, TP ; Gunn, GB ; Rosenthal, DI ; Fuller, CD ; Frank, SJ ; Garden, AS ; Reddy, JP ; Morrison, WH ; Ferrarotto, R ; Hanna, EY ; DeMonte, F ; Su, SY ; Phan, J (WILEY, 2020-03)
    PURPOSE: To report cancer control outcomes and health-related quality of life (HRQoL) outcomes after highly conformal skull-based re-irradiation (re-RT). METHODS: Patients planned for curative intent re-RT to a recurrent or new skull base tumor were enrolled. HRQoL were assessed using the MD Anderson Symptom Inventory Brain Tumor (MDASI-BT) and the anterior skull base surgery quality of life (ASBQ) questionnaires. RESULTS: Thirty-nine patients were treated with stereotactic body RT or intensity modulated RT. Median follow-up was 14 months. Progression free survival was 71% at 1-year. There was mild clinically significant worsening of fatigue, lack of appetite and drowsiness (MDASI-BT), and physical function (ASBQ) at the end of RT, followed by recovery to baseline on subsequent follow-ups. Subjective emotions were clinically improved at 12 months, with patients reporting feeling less tense/nervous. CONCLUSION: Conformal skull base re-RT is associated with mild immediate deterioration in physical function followed by rapid and sustained recovery.
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    Surveillance imaging for patients with head and neck cancer treated with definitive radiotherapy: A partially observed Markov decision process model
    Ng, SP ; Ajayi, T ; Schaefer, AJ ; Pollard, C ; Bahig, H ; Garden, AS ; Rosenthal, DI ; Gunn, GB ; Frank, SJ ; Phan, J ; Morrison, WH ; Johnson, JM ; Mohamed, ASR ; Sturgis, EM ; Fuller, CD (WILEY, 2020-02-15)
    BACKGROUND: A possible surveillance model for patients with head and neck cancer (HNC) who received definitive radiotherapy was created using a partially observed Markov decision process. The goal of this model is to guide surveillance imaging policies after definitive radiotherapy. METHODS: The partially observed Markov decision process model was formulated to determine the optimal times to scan patients. Transition probabilities were computed using a data set of 1508 patients with HNC who received definitive radiotherapy between the years 2000 and 2010. Kernel density estimation was used to smooth the sample distributions. The reward function was derived using cost estimates from the literature. Additional model parameters were estimated using either data from the literature or clinical expertise. RESULTS: When considering all forms of relapse, the model showed that the optimal time between scans was longer than the time intervals used in the institutional guidelines. The optimal policy dictates that there should be less time between surveillance scans immediately after treatment compared with years after treatment. Comparable results also held when only locoregional relapses were considered as relapse events in the model. Simulation results for the inclusive relapse cases showed that <15% of patients experienced a relapse over a simulated 36-month surveillance program. CONCLUSIONS: This model suggests that less frequent surveillance scan policies can maintain adequate information on relapse status for patients with HNC treated with radiotherapy. This model could potentially translate into a more cost-effective surveillance program for this group of patients.
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    Head and neck cancer patient images for determining auto-segmentation accuracy in T2-weighted magnetic resonance imaging through expert manual segmentations
    Cardenas, CE ; Mohamed, ASR ; Yang, J ; Gooding, M ; Veeraraghavan, H ; Kalpathy-Cramer, J ; Ng, SP ; Ding, Y ; Wang, J ; Lai, SY ; Fuller, CD ; Sharp, G (WILEY, 2020-05-01)
    PURPOSE: The use of magnetic resonance imaging (MRI) in radiotherapy treatment planning has rapidly increased due to its ability to evaluate patient's anatomy without the use of ionizing radiation and due to its high soft tissue contrast. For these reasons, MRI has become the modality of choice for longitudinal and adaptive treatment studies. Automatic segmentation could offer many benefits for these studies. In this work, we describe a T2-weighted MRI dataset of head and neck cancer patients that can be used to evaluate the accuracy of head and neck normal tissue auto-segmentation systems through comparisons to available expert manual segmentations. ACQUISITION AND VALIDATION METHODS: T2-weighted MRI images were acquired for 55 head and neck cancer patients. These scans were collected after radiotherapy computed tomography (CT) simulation scans using a thermoplastic mask to replicate patient treatment position. All scans were acquired on a single 1.5 T Siemens MAGNETOM Aera MRI with two large four-channel flex phased-array coils. The scans covered the region encompassing the nasopharynx region cranially and supraclavicular lymph node region caudally, when possible, in the superior-inferior direction. Manual contours were created for the left/right submandibular gland, left/right parotids, left/right lymph node level II, and left/right lymph node level III. These contours underwent quality assurance to ensure adherence to predefined guidelines, and were corrected if edits were necessary. DATA FORMAT AND USAGE NOTES: The T2-weighted images and RTSTRUCT files are available in DICOM format. The regions of interest are named based on AAPM's Task Group 263 nomenclature recommendations (Glnd_Submand_L, Glnd_Submand_R, LN_Neck_II_L, Parotid_L, Parotid_R, LN_Neck_II_R, LN_Neck_III_L, LN_Neck_III_R). This dataset is available on The Cancer Imaging Archive (TCIA) by the National Cancer Institute under the collection "AAPM RT-MAC Grand Challenge 2019" (https://doi.org/10.7937/tcia.2019.bcfjqfqb). POTENTIAL APPLICATIONS: This dataset provides head and neck patient MRI scans to evaluate auto-segmentation systems on T2-weighted images. Additional anatomies could be provided at a later time to enhance the existing library of contours.
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    Original Lymphopenia during radiotherapy in patients with oropharyngeal cancer
    Ng, SP ; Bahig, H ; Jethanandani, A ; Pollard, C ; Berends, J ; Sturgis, EM ; Johnson, FM ; Elgohari, B ; Elhalawani, H ; Rosenthal, D ; Skinner, HD ; Gunn, GB ; Phan, J ; Frank, SJ ; Mohamed, ASR ; Fuller, CD ; Garden, AS (ELSEVIER IRELAND LTD, 2020-04)
    PURPOSE/OBJECTIVE: Radiation-induced lymphopenia has been associated with poor survival outcomes in certain solid tumors such as esophageal, lung, cervical and pancreatic cancers. We aim to determine the effect of treatment-related lymphopenia during radiotherapy on outcomes of patients with oropharyngeal cancer. MATERIALS/METHODS: A retrospective analysis of all patients who completed definitive radiotherapy for oropharyngeal cancer at The University of Texas MD Anderson Cancer Center and had blood counts taken during radiotherapy from 2002 to 2013 were included. Patient, tumor and treatment characteristics, clinical outcomes and lymphocyte counts during radiotherapy were recorded. Lymphopenia was graded according to the CTCAE v4.0. Survival rates were estimated using the Kaplan-Meier method and compared with log-rank tests. RESULTS: 850 patients were evaluated. The median age was 57 years. The majority of the cohort had p16/HPV-positive disease (71%), 8% had HPV-negative disease and 21% were unknown. The median radiation total dose was 70 Gy. 45% of patients had induction chemotherapy, and 87% had concurrent chemotherapy. 703 (83%) patients developed ≥grade 3 (G3) lymphopenia and 209 (25%) had grade 4 (G4) lymphopenia during radiotherapy. The median follow-up was 59 months; the 5-year overall survival rate was 81%. There were no significant differences in overall survival rates nor in disease control rates, in those who developed G3/G4 lymphopenia compared with those who did not. No significant effect of lymphopenia on survival was observed when analyzed according to p16/HPV status. CONCLUSION: In this large cohort of patients with oropharyngeal cancer, the development of lymphopenia during radiotherapy did not impact outcomes.
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    Longitudinal characterization of the tumoral microbiome during radiotherapy in HPV-associated oropharynx cancer
    Bahig, H ; Fuller, CD ; Mitra, A ; Yoshida-Court, K ; Solley, T ; Ng, SP ; Abu-Gheida, I ; Elgohari, B ; Delgado, A ; Rosenthal, D ; Garden, AS ; Frank, SJ ; Reddy, JP ; Colbert, L ; Klopp, A (ELSEVIER IRELAND LTD, 2021-01)
    PURPOSE: To describe the baseline and serial tumor microbiome in HPV-associated oropharynx cancer (OPC) over the course of radiotherapy (RT). METHODS: Patients with newly diagnosed HPV-associated OPC treated with definitive radiotherapy +/- concurrent chemotherapy were enrolled in this prospective study. Using 16S rRNA gene sequencing, dynamic changes in the tumor site microbiome during RT were investigated. Surface tumor samples were obtained before RT and at week 1, 3 and 5 of RT. Radiological primary tumor response at mid-treatment was categorized as complete (CR) or partial (PR). RESULTS: Ten patients were enrolled, but 9 patients were included in the final analysis. Mean age was 62 years (range: 51-71). As per AJCC 8th Ed, 56%, 22% and 22% of patients had stage I, II and III, respectively. At 4-weeks, 6 patients had CR and 3 patients had PR; at follow-up imaging post treatment, all patients had CR. The baseline diversity of the tumoral versus buccal microbiome was not statistically different. For the entire cohort, alpha diversity was significantly decreased over the course of treatment (p = 0.04). There was a significant alteration in the bacterial community within the first week of radiation. Baseline tumor alpha diversity of patients with CR was significantly higher than those with PR (p = 0.03). While patients with CR had significant reduction in diversity over the course of radiation (p = 0.01), the diversity remained unchanged in patients with PR. Patients with history of smoking had significantly increased abundance of  Kingella (0.05) and lower abundance of Stomatobaculum (p = 0.03) compared to never smokers. CONCLUSIONS: The tumor microbiome of HPV-associated OPC exhibits reduced alpha diversity and altered taxa abundance over the course of radiotherapy. The baseline bacterial profiles of smokers vs. non-smokers were inherently different. Baseline tumor alpha diversity of patients with CR was higher than patients with PR, suggesting that the microbiome deserves further investigation as a biomarker of radiation response.
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    Comparison of tumor delineation using dual energy computed tomography versus magnetic resonance imaging in head and neck cancer re-irradiation cases.
    Ng, SP ; Cardenas, CE ; Elhalawani, H ; Pollard, C ; Elgohari, B ; Fang, P ; Meheissen, M ; Guha-Thakurta, N ; Bahig, H ; Johnson, JM ; Kamal, M ; Garden, AS ; Reddy, JP ; Su, SY ; Ferrarotto, R ; Frank, SJ ; Brandon Gunn, G ; Moreno, AC ; Rosenthal, DI ; Fuller, CD ; Phan, J (Elsevier BV, 2020-04)
    In treatment planning, multiple imaging modalities can be employed to improve the accuracy of tumor delineation but this can be costly. This study aimed to compare the interobserver consistency of using dual energy computed tomography (DECT) versus magnetic resonance imaging (MRI) for delineating tumors in the head and neck cancer (HNC) re-irradiation scenario. Twenty-three patients with recurrent HNC and had planning DECT and MRI were identified. Contoured tumor volumes by seven radiation oncologists were compared. Overall, T1c MRI performed the best with median DSC of 0.58 (0-0.91) for T1c. T1c MRI provided higher interobserver agreement for skull base sites and 60 kV DECT provided higher interobserver agreement for non-skull base sites.
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    Conventionally fractionated large volume head and neck re-irradiation using multileaf collimator-based robotic technique: A feasibility study
    Bahig, H ; Wang, C ; Ng, SP ; Phan, J (ELSEVIER IRELAND LTD, 2020-09)
    PURPOSE: To report on the feasibility and performance of conventionally fractionated multileaf collimator (MLC)-based robotic stereotactic body re-irradiation of the head and neck region using MLC-based Cyberknife (CK) technology. METHODS: Patients treated for recurrent or second primary head and neck cancer (HNC) with curative proton therapy to a target volume > 30 cm3 between 2011 and 2015 were included. MLC-based CK plans were generated using the CK M6 InCise2 MLC system. Dose statistics from MLC-based CK plans were compared to proton beam therapy (PBT) plans according to the following metrics: target coverage, target homogeneity index, gradient index, Paddick conformity index (CI), prescription isodose volume (PIV), treatment time (tTime) for one fraction as well as doses to organs at risk (OAR). Wilcoxon signed-rank test was used to compare dose metrics. RESULTS: Eight patients were included; the tumor sites included: salivary glands, pharynx (oropharynx, hypopharynx and retropharynx) and sinonasal cavities. Five of 8 patients were treated with multifield optimisation intensity modulated proton therapy, 3 were treated with passive scattering proton therapy. Median dose was 67 Gy (range 60-70) in 32 fractions (range 30-35). The median high-dose planning target volume (PTV) was 45.4 cm3 (range 2.4 - 130.2 cm3) and the median elective PTV was 91.9 cm3 (range 61.2 - 269.7 cm3). Overall, the mean target coverage (mean 98.3% vs. 96.2% for CK vs. PBT, respectively), maximum dose to PTV (mean 111% vs. 111%, p = 0.2) and mean dose to PTV (mean 104% vs. 104%) were similar across modalities. Highly conformal plans were achieved with both modalities, but mean CI was better with PBT (0.5 vs. 0.6 for CK vs. PBT, p = 0.04). Homogeneity and gradient indexes were similar between the 2 modalities; mean tTime with PBT and CK was 17 vs. 18 min, respectively (p = 0.7). Case-based study revealed that CK and PBT plans allowed for excellent sparing of OAR, with some clinical scenarios associated with better performance of CK while others with better performance of PBT. CONCLUSION: Our study has demonstrated the dosimetric performance of large volume head and neck re-irradiation using MLC-based CK in various clinical scenarios. While conformity was generally better achieved with PBT, MLC-based CK allowed for high dose gradient leading to rapid dose drop-off and sparing of OAR. Conventionally fractionated MLC-based CK could be a competitive alternative in large volume head and neck re-irradiation that deserves further investigation in the clinical setting.
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    Automatic registration of 2D MR cine images for swallowing motion estimation
    Yang, J ; Mohamed, ASR ; Bahig, H ; Ding, Y ; Wang, J ; Ng, SP ; Lai, S ; Miller, A ; Hutcheson, KA ; Fuller, CD ; Zheng, D (PUBLIC LIBRARY SCIENCE, 2020-02-11)
    PURPOSE: To automate the estimation of swallowing motion from 2D MR cine images using deformable registration for future applications of personalized margin reduction in head and neck radiotherapy and outcome assessment of radiation-associated dysphagia. METHODS: Twenty-one patients with serial 2D FSPGR-MR cine scans of the head and neck conducted through the course of definitive radiotherapy for oropharyngeal cancer. Included patients had at least one cine scan before, during, or after radiotherapy, with a total of 52 cine scans. Contours of 7 swallowing related regions-of-interest (ROIs), including pharyngeal constrictor, epiglottis, base of tongue, geniohyoid, hyoid, soft palate, and larynx, were manually delineated from consecutive frames of the cine scan covering at least one swallowing cycle. We applied a modified thin-plate-spline robust-point-matching algorithm to register the point sets of each ROI automatically over frames. The deformation vector fields from the registration were then used to estimate the motion during swallowing for each ROI. Registration errors were estimated by comparing the deformed contours with the manual contours. RESULTS: On average 22 frames of each cine scan were contoured. The registration for one cine scan (7 ROIs over 22 frames) on average took roughly 22 minutes. A number of 8018 registrations were successfully batch processed without human interaction after the contours were drawn. The average registration error for all ROIs and all patients was 0.36 mm (range: 0.06 mm- 2.06 mm). Larynx had the average largest motion in superior direction of all structures under consideration (range: 0.0 mm- 58.7 mm). Geniohyoid had the smallest overall motion of all ROIs under consideration and the superior-inferior motion was larger than the anterior-posterior motion for all ROIs. CONCLUSION: We developed and validated a deformable registration framework to automate the estimation of swallowing motion from 2D MR cine scans.