Faculty Bibliography

OBJECTIVE:Radiobiological models have been used to calculate the outcomes of treatment plans based on dose-volume relationship. This study examines several radiobiological models for the calculation of tumor control probability (TCP) of intensity modulated radiotherapy plans for the treatment of lung, prostate, and head and neck (H&N) cancers. METHODS:Dose volume histogram (DVH) data from the intensity modulated radiotherapy plans of 36 lung, 26 prostate, and 87  H&N cases were evaluated. The Poisson, Niemierko, and Marsden models were used to calculate the TCP of each disease group treatment plan. The calculated results were analyzed for correlation and discrepancy among the three models, as well as different treatment sites under study. RESULTS:The median value of calculated TCP in lung plans was 61.9% (34.1-76.5%), 59.5% (33.5-73.9%) and 32.5% (0.0-93.9%) with the Poisson, Niemierko, and Marsden models, respectively. The median value of calculated TCP in prostate plans was 85.1% (56.4-90.9%), 81.2% (56.1-88.7%) and 62.5% (28.2-75.9%) with the Poisson, Niemierko, and Marsden models, respectively. The median value of calculated TCP in H&N plans was 94.0% (44.0-97.8%) and 94.3% (0.0-97.8%) with the Poisson and Niemierko models, respectively. There were significant differences between the calculated TCPs with the Marsden model in comparison with either the Poisson or Niemierko model (p < 0.001) for both lung and prostate plans. The TCPs calculated by the Poisson and Niemierko models were significantly correlated for all three tumor sites. CONCLUSION/CONCLUSIONS:There are variations with different radiobiological models. Understanding of the correlation and limitation of a TCP model with dosimetric parameters can help develop the meaningful objective functions for plan optimization, which would lead to the implementation of outcome-based planning. More clinical data are needed to refine and consolidate the model for accuracy and robustness. Advances in knowledge: This study has tested three radiobiological models with varied disease sites. It is significant to compare different models with the same data set for better understanding of their clinical applicability.

PURPOSE/OBJECTIVE:The International Lymphoma Radiation Oncology Group (ILROG) published consensus guidelines on the management of Hodgkin disease (HD) and nodal non-Hodgkin lymphoma (NHL), which became the most downloaded articles from International Journal of Radiation Oncology, Biology, and Physics. E-contouring workshops allow for interactive didactic sessions, allowing participants to see case-based contouring in real time. A pilot 1-hour curriculum was developed with the objective of reviewing ILROG guidelines for HD and NHL management with incorporation of e-contouring tools. This represents the first international education intervention in Spanish using e-contouring with a pre- and postintervention questionnaire. METHODS:A 1-hour presentation was prepared in Spanish reviewing the ILROG recommendations for HD and NHL. The review was followed by the author's demonstration of contour creation using patients with HD and NHL prepared for the American Society for Radiation Oncology's 2015 e-contouring lymphoma session. A five- question evaluation was prepared and administered before and after intervention. A two-tailed paired t test was performed to evaluate any significant change in test value before and after intervention. RESULTS:A total of nine quizzes were collected before and after the intervention. The average test score before the intervention was 75.6%, and the average test score after the intervention was 86.7% ( P = .051). Four students scored 100% on both the pre- and postintervention evaluations, and no student had a decrease in score from pre- to postintervention evaluation. The topic with the lowest score tested dose consideration. CONCLUSION/CONCLUSIONS:A substantial but nonsignificant improvement in test evaluation was seen with this pilot curriculum. This pilot intervention identified obstacles for truly interactive didactic sessions that, when addressed, can lead to fully developed interactive didactic sessions.

Introduction Photobiomodulation (PBM Therapy) formerly known as Low Level Laser Therapy (LLLT) is an effective treatment for reducing the incidence and severity of oral mucositis (OM) after high dose chemotherapy and/or radiotherapy. However, reported PBM irradiation parameters, dose per point, number of treatment points or treatment intervals vary widely Objectives To systematically review randomized clinical trials (RCTs), summarise the PBM parameters and detain the most effective treatment regimen. Methods Online databases were searched for RCTs comparing efficacy of PBM verses controls for prevention or treatment cancer therapy induced OM. Papers were scored for quality and effect size for the primary outcome, irradiation parameters and dose were compared with outcomes. Results There was lots of mistakes and missing treatment data (i.e. laser wavelength ranges, power, beam sizes, energy applied and treatment duration) on the reported data, however the majority of the randomized clinical trials reported positive effects: PBM reduced pain, onset of OM, and improved overall quality of life of the patients that received PBM. Conclusions Although no precise conclusion can be drawn due to a large variation on the reported data, PBM used for OM confidently recommend an optimal treatment guideline for this condition

OBJECTIVES/HYPOTHESIS/OBJECTIVE:To assess patterns of care and outcomes with the use of neoadjuvant chemotherapy followed by definitive radiation in local-regionally advanced nasopharyngeal carcinoma. STUDY DESIGN/METHODS:Retrospective database analysis. METHODS:We queried the National Cancer Database for patients with T3-4N2 or T1-4N3 nasopharyngeal carcinoma who received concurrent chemoradiotherapy or neoadjuvant chemotherapy followed by radiation. Overall survival (OS) was analyzed using the Kaplan-Meier method, propensity-score matching, and a Cox proportional hazards model adjusting for demographic and disease-specific prognostic factors. RESULTS:P = .001). At a median follow-up of 36.6 months, patients had 3-year OS of 66% in the neoadjuvant group compared with 70% in those who received concurrent chemoradiotherapy (log rank P = .29). On subgroup analysis by histology, T stage, and N stage, there remained no differences in OS between the two groups. On multivariable analysis, there was no significant survival difference associated with neoadjuvant chemotherapy (adjusted hazard ratio [HR]: 1.05, 95% confidence interval [CI]: 0.89-1.25, P = .54). In a propensity score-matched population of 1,008 patients (504 with neoadjuvant therapy and 504 without), there was no significant survival difference associated with neoadjuvant chemotherapy (H: 1.13, 95% CI: 0.93-1.38, P = .22). CONCLUSIONS:Neoadjuvant chemotherapy was used in over 25% of patients, and its use is increasing. However, neoadjuvant chemotherapy was not associated with any differences in survival compared to concurrent chemoradiotherapy. LEVEL OF EVIDENCE/METHODS:4 Laryngoscope, 2018.

Purpose: Rapid dose fall off from planning target volume (PTV) is required to spare organs at risk (OAR) that is hallmark of advanced treatment techniques (IMRT, VMAT, and SBRT). Along with conformity index (CI) and homogeneity index (HI) recently, gradient index (GI) was introduced to provide a measurable quality index for dose fall off from PTV. However, it is not clear if GI can be used in IMRT and if there are consistent differences between the two techniques. Methods: Dose volume histogram data for 700 patients equally divided between SBRT and IMRT were retrospectively analyzed. GI was calculated for each patient which is ratio of the volume of at half the prescription (PIV50%) to prescription isodose volume (PIV100%) which was calculated treatment plan and from PTV and CI. Physical distance ratio between OAR and PTV coverage was determined based on the cube root of the GI as an additional tool along with gradient measure distance (rPIV50%-rPIV100%) for the evaluation of SBRT and IMRT plans. Results: The GI varied widely between IMRT and SBRT patients due to inherent differences in techniques. The GIs are nearly constant 4.3 +/-1.1 and 12.8 +/-4.4 for SBRT and IMRT, respectively. The size of PTV is inversely related to GI with data more consistent in SBRT compared to IMRT. The gradient measure increases with PTV size in a well-defined way (0.5-1.5 cm) compared to IMRT where data is widely spread. This can be used as a surrogate for distance between PTV and OAR in IMRT and SBRT. Conclusion: Gradient index and measure are effective parameters in evaluating dose gradient that show consistent differences between treatment techniques. These tools could provide an opportunity for plan evaluation especially the distance from the PTV to OAR to optimize the dose to reduce complications

Objective To analyze the patterns of care and survival for pT1-2N1M0 head and neck cancer based on receipt of surgery alone, surgery + postoperative radiotherapy (S + RT), or surgery + postoperative chemoradiotherapy (S + CRT). Study Design Retrospective analysis. Setting National Cancer Database. Subjects and Methods We queried the database for patients with stage pT1-2N1M0 squamous cell carcinoma of the oral cavity, oropharynx, hypopharynx, or larynx between 2004 and 2012 who were treated with surgery with negative margins and no extracapsular extension. Logistic regression was used to assess predictors of receipt of postoperative treatment. Overall survival was assessed by the Kaplan-Meier method, and Cox regression analysis identified covariates that affected it. Results There were 1598 patients included in this study: 566 (35.4%) received surgery alone; 726 (45.4%), S + RT; and 306 (19.1%), S + CRT. The 5-year overall survival was 68.8%, 74.0%, and 87.8%, respectively ( P = .009 comparing S + RT and surgery alone, P < .001 for all other comparisons). On multivariable logistic regression, academic centers were associated with a decreased likelihood of S + RT (odds ratio = 0.71) and S + CRT (odds ratio = 0.66). Multivariable Cox regression demonstrated no difference in survival for S + RT over surgery alone (hazard ratio = 0.88, 95% CI = 0.70-1.09, P = .24); however, there was a survival benefit associated with S + CRT (hazard ratio = 0.57, 95% CI = 0.39-0.81, P = .002). Conclusion Nearly 65% of patients with pT1-2N1 head and neck cancer with negative margins and no extracapsular extension received S + RT or S + CRT. Improvement in survival was noted only for patients who received S + CRT.