Utilization Of Intensity-modulated Radiation Therapy Research Articles

Trends in IMRT Utilization for Definitive Treatment of Cervical Cancer, 2004-2018

<h3>Purpose/Objective(s)</h3> Intensity-modulated radiation therapy (IMRT) is an advanced radiotherapy technique that delivers conformal radiation to desired targets while minimizing dose to surrounding organs at risk. In the post-operative setting, IMRT is associated with reduced acute and late genitourinary and gastrointestinal side effects for patients with cervical cancer. However, no prospective randomized data exist for the use of IMRT in the setting of definitive treatment of intact cervical cancer. The objective of this study was to identify trends in IMRT use for this population. <h3>Materials/Methods</h3> Patients with stage IB2-IVA cervical cancer diagnosed from 2004-2018 who were treated with curative intent chemoradiation were identified in the National Cancer Database. Patients who underwent primary surgical management, did not receive external beam radiation to the pelvis or received radiation outside the pelvis, or received an unspecified technique or target of radiation were excluded. The primary outcome of interest was utilization of IMRT vs 3D conformal radiotherapy (3D-CRT) over time. A Cochrane-Armitage test was performed to assess trends over time. T-tests, chi-square tests, and multivariable logistic regression with propensity score matching were used to identify factors associated with receipt of IMRT. <h3>Results</h3> Overall, 13,974 patients met inclusion criteria; 4,590 (33%) received IMRT, and 9,384 (67%) received 3DCRT. In this cohort, 65% were non-Hispanic White, 45% were early stage (I-II), 80% were squamous histology, 62% received brachytherapy, and 28% had lymph node involvement. The utilization of IMRT increased from 30% in 2004 to 71% in 2018 (p<0.001). After adjustment for clinical and demographic variables, factors associated with IMRT use were: Hispanic ethnicity (adjusted odds ratio [aOR] 1.2, 95% confidence interval [CI] 1.0-1.5), treatment in the Western U.S. (aOR 1.4, CI 1.2-1.7) and the Southern U.S. (aOR 1.3, CI 1.1-1.5), living more than 50 miles from the treatment facility (aOR 1.2, CI 1.0-1.5), stage III disease (aOR 1.3, CI 1.1-1.5), and lymph node involvement (aOR 1.4, CI 1.3-1.6). Compared to an academic medical center, patients receiving care at a comprehensive community cancer center were less likely to receive IMRT (aOR 0.66, CI 0.59-0.72). There were no differences in IMRT use by age, insurance, or medical comorbidities. <h3>Conclusion</h3> Despite the lack of prospective efficacy data supporting the use of IMRT in patients with intact cervical cancer, IMRT has dramatically increased over the last fifteen years especially for patients with advanced-stage disease or lymph node involvement. More data on the optimal use of IMRT, including appropriate target volume margins and on-board imaging, are needed.

Worsening Racial Disparities in Utilization of Intensity Modulated Radiation Therapy

PurposeThe benefits of intensity modulated radiation therapy (IMRT) compared with standard 3-dimensional conformal radiation therapy have been demonstrated in many cancer sites and include decreased acute and late toxicity, improved quality of life, and opportunities for dose escalation. Limited literature suggests non-white patients may have lower utilization of IMRT. We hypothesized that as the use of IMRT has increased in recent years, racial inequities have persisted and disproportionately affect non-Hispanic Black (NHB) patients. We aim to evaluate temporal trends in IMRT utilization focusing on disparities among minoritized populations. Methods and MaterialsThe National Cancer Database was queried to identify the 10 disease sites with the highest total number of cancer patients treated with definitive intent IMRT in 2017, the most recent year for which data are available. Exclusions included stage IV, age <18 years, unknown insurance status, unknown race, and palliative intent radiation. Race and ethnicity variables were combined and classified as non-Hispanic White, Hispanic, NHB, Asian, Native American/Eskimo, and Hawaiian/Pacific Islander. Multivariable logistic regression for IMRT utilization was performed for each disease site for both early (2004-2010) and contemporary (2011-2017) cohorts, adjusting for clinical and demographic covariates. ResultsAmong the 10 selected disease sites, 1,010,292 patients received radiation therapy as part of definitive treatment between 2004 and 2017. Overall IMRT utilization rates increased from 22.0% in 2004 to 57.8% in 2017. After adjustment and compared with non-Hispanic White patients, NHB patients were significantly less likely to receive IMRT in 1 of 10 disease sites in the 2004 to 2010 cohort, and 5 of 10 disease sites in the 2011 to 2017 cohort. ConclusionsDespite greater awareness of racial disparities in cancer care and outcomes, this study demonstrates worsening disparities in the use of IMRT, particularly for NHB patients. These differences may exacerbate racial disparities in cancer outcomes; therefore, identification of underlying drivers of differential IMRT utilization is warranted.

Utilization of IMRT and Brachytherapy for Low-Risk and Intermediate-Risk Prostate Cancer Patients: Analysis of the RealWorld Scenario

Purpose: Two main techniques in radiation therapy (RT) for the treatment of low-risk and intermediate-risk prostate cancer (PCa) are intensity-modulated radiation therapy (IMRT) and brachytherapy (BT). In this study, the pattern of utilization of IMRT, low dose-rate (LDR) BT, and high dose-rate (HDR) BT has been evaluated using a large hospital based registry database. Methods: We analyzed a very large data set of N0, M0, non-surgical, stage T1-T2c prostate cancer patients diagnosed between 2004 and 2015 from the National Cancer Database (NCDB). Based on the RT techniques used, we considered three groups of patients: (1) IMRT (n=61,159; 48.4%) who received an initial as well as a boost treatment with the IMRT, (2) BT LDR (n=43,293; 34.3%), and (3) BT HDR (n=21,938; 17.3%). A total dose of 70-81Gy for IMRT was considered. For brachytherapy, LDR and HDR or unspecified brachytherapy was considered as monotherapy. Patients were stratified according to the National Comprehensive Cancer Network (NCCN) guidelines into: low-risk [clinical stage T1-T2a, Gleason Score (GS) of ≤ 6 (Grade Group 1), and Prostate-specific antigen (PSA) of &lt; 10 ng/mL] and intermediate-risk [clinical stage T2b-T2c, GS of 7 (Grade Groups 2 and 3), and PSA of 10-20 ng/mL]. OS probability was determined using the Kaplan-Meier estimator. Propensityscore matched (PSM) analysis was performed for each risk group (low and intermediate) for the three research treatment modalities (IMRT, BT LDR, and BT HDR). IBM SPSS software was used for statistical analysis; p-value &lt;0.05 was considered statistically significant. Results: There has been a relative increase in IMRT usage for the treatment of both low-risk (29% to 53%) and intermediaterisk (53% to 77%) PCa patients from 2004 to 2015. Observed comparable median OS in low-risk and intermediate-risk patients in these three modalities IMRT (74.8/63.4 mo.), LDR (77.7/65.7 mo.) and HDR (83.5/72.1 mo.). Conclusion: The pattern of utilization of RT modality seems inclined toward increased use of IMRT over brachytherapy (59% vs. 41%) for both the low-risk and intermediate-risk PCa patients. Over the years, use of IMRT increased more in low-risk patient group than in intermediate-risk group.

Hypofractionated radiation in older women with breast cancer.

American Society of Radiation Oncology Choosing Wisely campaign recommends hypofractionated radiation and against routine use of intensity-modulated radiation therapy (IMRT) in early-stage estrogen receptor-positive breast cancer. We analyzed guideline recommendation adherence and financial implications in a modern Medicare cohort of women treated across the southeastern United States. Our study population comprised Medicare patients over 65years of age with breast cancer diagnosis from 12 cancer centers in the Southeast United States with stage 0-II breast treated with lumpectomy from 2012 to 2015. Hypofractionation was defined as 4 or fewer weeks of radiation treatments. Factors associated with utilization of hypofractionation and IMRT were identified using Poisson regression. Median costs during radiation treatments were compared for hypofractionation and IMRT. In older women (median age 71), 75% were treated with conventional fractionation, and 20% received IMRT. Hypofractionated women were more likely to have a positive estrogen(ER) or progestorone(PR) receptor status, lower comorbidity scores, and be treated at a high volume center (all P<0.05). IMRT was utilized in 20% of patients and was more common in women treated with conventional fractionation (P<0.001). Positive ER/PR status (P<0.001) and utilization of hormonal blockade (P=0.02) were associated with increased utilization of IMRT. In an older cohort of patients with early-stage breast cancer, a majority were treated with conventional fractionated radiation, while approximately 20% were treated with IMRT. Both of which were associated with increased cost relative to hypofractionation.

Management for locally advanced cervical cancer: new trends and controversial issues.

This article reviewed new trends and controversial issues, including the intensification of chemotherapy and recent brachytherapy (BT) advances, and also reviewed recent consensuses from different societies on the management of locally advanced cervical cancer (LACC). Intensive chemotherapy during and after radiation therapy (RT) was not recommended as a standard treatment due to severe toxicities reported by several studies. The use of positron emission tomography-computed tomography (PET-CT) and magnetic resonance imaging (MRI) for pelvic RT planning has increased the clinical utilization of intensity-modulated radiation therapy (IMRT) for the evaluation of pelvic lymph node metastasis and pelvic bone marrow. Recent RT techniques for LACC patients mainly aim to minimize toxicities by sparing the normal bladder and rectum tissues and shortening the overall treatment time by administering a simultaneous integrated boost for metastatic pelvic lymph node in pelvic IMRT followed by MRI-based image guided adaptive BT.

Impact of Medicare Advantage Enrollment on Utilization of Intensity-Modulated Radiation Therapy and Cost of Care for Cancer Treatment

Intensity-modulated radiation therapy (IMRT) is an important driver of rising costs in oncology care, but the level of evidence supporting its routine use varies across disease sites, including breast, lung, and prostate. While Medicare Advantage (MA) plans have incentives to reduce health care spending, the effect of MA enrollment on utilization of high-cost medical services and quality of care is unclear, especially for cancer patients. We examined differences in IMRT utilization and health care spending between MA and traditional fee-for-service (FFS) Medicare for patients receiving radiation therapy (RT) across these disease sites. We performed a retrospective cohort study using 2009-2012 health insurance claims data from the Health Care Cost Institute (HCCI) and the Centers for Medicare and Medicaid Services (CMS). We identified 2,571 MA and 6,062 FFS Medicare beneficiaries from the HCCI and CMS databases, respectively, who were newly diagnosed with non-metastatic breast, lung, or prostate cancer in 2011 and were treated with external beam RT within 12 months of diagnosis. We measured utilization rate of IMRT, unit price of RT delivery, and RT-specific spending among patients within each cancer-type cohort. Outcomes were adjusted for differences in patient characteristics (age, sex, and Charlson co-morbidity index) and geography between MA and FFS beneficiaries. Statistical significance of the differences between groups was assessed using two-sample t tests. In both MA and FFS Medicare, the adjusted rate of IMRT utilization was highest among prostate patients and lowest among breast patients. Across all three disease sites, IMRT utilization was lower in MA than FFS Medicare, but the difference was statistically significant only for the prostate cohort (18.0 vs. 20.2%, p=0.149 for breast; 32.8 vs. 36.0%, p=0.385 for lung; 94.0 vs. 98.5%, p<0.001 for prostate). Average unit price of IMRT delivery was not significantly different in MA versus FFS Medicare. However, per patient RT-related costs were lower among MA patients in the breast and prostate cancer cohorts ($12,630 vs. $13,214 and $25,990 vs. $27,685, respectively; p=0.005 and p<0.001), but not significantly different among lung cancer patients ($15,653 vs. $15,024; p=0.301). IMRT utilization rates in both MA and FFS Medicare were consistent with the relative level of evidence supporting its use in each disease site. MA enrollment was associated with modestly lower IMRT utilization for all patients, with no evidence of a differential impact based on cancer type. The unit price of IMRT delivery was similar in MA versus FFS Medicare. We found no evidence that MA plans adopted utilization management tools that more effectively targeted high-cost therapies based on clinical evidence than in traditional Medicare.

Utilization of Intensity-Modulated Radiation Therapy for Malignant Pleural Mesothelioma in the United States

BackgroundAlthough postoperative radiotherapy (RT) for malignant pleural mesothelioma (MPM) has historically been delivered using 3-dimensional conformal RT (3DCRT) techniques, multiple reports show noteworthy safety and efficacy of the more advanced intensity-modulated RT (IMRT). To our knowledge, this is the only known study to evaluate national practice patterns of IMRT utilization for MPM. Materials and MethodsThe National Cancer Data Base was queried for newly-diagnosed MPM patients who underwent definitive surgery (extrapleural pneumonectomy [EPP] or extended pleurectomy/decortication [P/D]) followed by adjuvant RT. Patients with metastatic disease, non-EPP or P/D surgical techniques, and lack of RT receipt (or without specified RT technique) were excluded. Statistics included multivariable logistic regression, Kaplan–Meier overall survival (OS) analysis, and Cox proportional hazards modeling. ResultsOverall, 286 patients met criteria (181 [63%] IMRT and 105 [37%] 3DCRT). Temporal trends revealed that although 3DCRT was more common at initial time periods, IMRT utilization rose from 2004 to 2007 and stayed as a relatively constant majority thereafter. This was also present when substratifying the cohort according to EPP versus P/D approaches. IMRT was more often delivered at academic centers, along with institutions in the Southern United States, whereas 3DCRT was more frequently utilized in community facilities and in the Northeast (P ≤ .05 for all). RT technique did not affect OS (P > .05 for all comparisons). ConclusionIn the United States, IMRT is now the most commonly utilized adjuvant RT technique for MPM. Facility and regional differences might associate with IMRT delivery. The findings of this investigation have implications for insurance coverage, clinical referral patterns, and ongoing and future prospective trial design.

Intensity Modulated Radiation Therapy in Muscle-Invasive Bladder Cancer: Predictors of Utilization and Survival Outcomes

Prior trials of concurrent chemoradiotherapy (CCRT) for muscle-invasive bladder cancer (MIBC) utilized either two-dimensional or three-dimensional conformal radiation therapy (3DCRT) techniques. Since completion of these trials, intensity modulated radiation therapy (IMRT) has often been used in MIBC with the goal of reducing toxicity and improving the therapeutic ratio, although this has not been validated in a randomized trial. Our objective was to explore the utilization of IMRT in MIBC and to determine if there is an association between IMRT and OS in the treatment of MIBC. Patients with cT2-4 N0-3 M0 transitional cell MIBC treated with definitive doses (≥60 Gy) of RT or CCRT were selected from the National Cancer Data Base. Chi-squared test was used to compare clinical, treatment, and sociodemographic covariates between patients treated with IMRT and those treated without IMRT. Predictors associated with IMRT use were determined using a multivariable (MVA) generalized linear mixed effects model that allowed for clustering of patients within their treatment facility type. The Kaplan-Meier method was used to estimate OS, and univariate analysis (UVA) was performed using the log rank test to identify the impact of covariates on OS. MVA for OS was performed using the Cox Proportional Hazards model, and included all covariates with p<0.1 on UVA. 2,527 patients treated with radiotherapy from 2004 to 2013 met eligibility criteria; 467 (18.5%) received IMRT and 2,064 (81.4%) received non-IMRT. IMRT utilization increased over time (9.2% in 2004-2007, 27.7% in 2012-2013, p<0.0001). Patients who lived 5 to 10 miles away from their treatment facility were 43% more likely to receive IMRT than those who lived less than 5 miles from their treatment facility (OR = 1.43, 95% CI: 1.05-1.94, p =.03). Controlling for distance and year, for every 10-year increase in age, patients were 13% more likely to receive IMRT treatment (OR = 1.13, 95% CI: 1.01-1.26, p =.04). UVA revealed IMRT (p=0.03), CCRT (p<0.0001), younger age (p<0.0001), lower Charlson-Deyo comorbidity score (p<0.0001), private insurance (p<0.0001), higher median income (p=0.01), and radiation therapy dose ≥64 Gy (p<0.001) were associated with improved OS. Higher T stage (p<0.0001) and N stage (p<0.0001) were associated with decreased OS. On MVA, controlling for the other covariates in the model, patients receiving IMRT had improved OS compared to those who did not (Hazard Ratio 0.85, 95% Confidence Interval: 0.75-0.97, p=0.02). Use of IMRT has increased over time in the definitive management of MIBC. Our study is hypothesis-generating in that patients receiving IMRT in our series had improved survival compared to those who did not. This may be due to better target coverage, reduced toxicity, or due to the use of image-guidance, although further study is necessary.

Intensity Modulated Radiation Therapy in Breast Cancer: Analysis of Medicare Data at 12 Institutions

The Choosing Wisely campaign recommends avoidance of intensity modulated radiation therapy (IMRT) to deliver whole breast radiation therapy as part of breast conservation therapy. The purpose of this project is to analyze IMRT usage in a cohort of Medicare patients in 5 states in the southeastern United States. Data were for Medicare patients > 65 years of age with breast cancer diagnosis from 12 cancer community networks affiliated with an academic center in Alabama, Mississippi, Georgia, Tennessee, and Florida. Eligible patients with AJCC 7 stage 0-III breast cancer who were treated with lumpectomy and subsequent radiation therapy (RT) from Quarter 1, 2012 to Quarter 1, 2015 were identified using ICD-9 and CPT/HCPCS codes. Adherence to guidelines was defined by utilization or omission of IMRT. Cost of treatment was calculated per patient per quarter over the first year from breast cancer diagnosis. A total of 1,235 patients treated with lumpectomy were identified, 802 (64.9%) of which were treated with radiation therapy. Median age at diagnosis was 71.2 (8.0 IQR) and 701 (87.4%) patients were white. Stage at diagnosis was as follows: 0: 15.3%, I: 51.5%, II: 19.3%, III: 2.5%. Median time from lumpectomy to start of radiation was 97 days (IQR 65 days). Average adherence at all sites to guideline recommendations was 80.4%. Average adherence by upper, middle, and lower tertile of sites was 97.3%, 84.1%, 51.4% respectively. Guideline adherence per year was relatively stable: 84.8% (2012), 75.8% (2013), and 82.3% (2014). IMRT use by stage was as follows: 0: 17.1%, I: 18.2%, II and III: 21.7%. Patients treated with IMRT had ∼29% increased cost ($8741 vs $6798/patient/quarter) over the first year after diagnosis. Compliance with guidelines was relatively high, but there was significant variability by sites. A disproportionate number of patients with Stage 0-I disease were treated with IMRT, possibly resulting in increased healthcare costs. Future studies would benefit from analysis of specific patient and physician factors driving use of more expensive modalities in the setting of early stage disease known to have good outcomes. The project described was supported by Grant Number 1C1CMS331023 from the Department of Health and Human Services, Centers for Medicare and Medicaid Services. The contents of this publication are solely the responsibility of the authors and do not necessarily represent the official views of the U.S. Department of Health and Human Services or any of its agencies. The research presented here was conducted by the awardee. Findings might or might not be consistent with or confirmed by the independent evaluation contractor.

Technical advancement improves survival in patients with locally advanced non-small cell lung cancer (LA-NSCLC) receiving definitive radiotherapy

This study aimed to evaluate the impact of technical advancement of radiation therapy in patients with LA-NSCLC receiving definitive radiotherapy (RT). Patients treated with definitive RT (≥50 Gy) between 2000 and 2010 were retrospectively reviewed. Overall survival (OS), cancer specific survival (CSS), locoregional progression-free survival (LRPFS), distant metastasis-free survival (DMFS) and progression-free survival (PFS) were calculated and compared among patients irradiated with different techniques. Radiation-induced lung injury (RILI) and esophageal injury (RIEI) were assessed according to the National Cancer Institute Common Terminology Criteria for Adverse Events 3.0 (NCI-CTCAE 3.0). A total of 946 patients were eligible for analysis, including 288 treated with two-dimensional radiotherapy (2D-RT), 209 with three-dimensional conformal radiation therapy (3D-CRT) and 449 with intensity-modulated radiation therapy (IMRT) respectively. The median follow-up time for the whole population was 84.1 months. The median OS of 2D-RT, 3D-CRT and IMRT groups were 15.8, 19.7 and 23.3 months, respectively, with the corresponding 5-year survival rate of 8.7%, 13.0% and 18.8%, respectively (P<0.001). The univariate analysis demonstrated significantly inferior OS, LRPFS, DMFS and PFS of 2D-RT than those provided by 3D-CRT or IMRT. The univariate analysis also revealed that the IMRT group had significantly loger LRPFS and a trend toward better OS and DMFS compared with 3D-CRT. Multivariate analysis showed that TNM stage, RT technique and KPS were independent factors correlated with all survival indexes. Compared with 2D-RT, the utilization of IMRT was associated with significantly improved OS, LRPFS, DMFS as well as PFS. Compared with 3D-CRT, IMRT provided superior DMFS (P=0.035), a trend approaching significance with regard to LRPFS (P=0.073) but no statistically significant improvement on OS, CSS and PFS in multivariate analysis. The incidence rates of RILI were significantly decreased in the IMRT group (29.3% vs. 26.6% vs.14.0%, P<0.001) whereas that of RIET rates were similar (34.7% vs. 29.7% vs. 35.3%, P=0.342) among the three groups. Radiation therapy technique is a factor affecting prognosis of LA-NSCLC patients. Advanced radiation therapy technique is associated with improved tumor control and survival, and decreased radiation-induced lung toxicity.

Photon and Proton Radiation Therapy Utilization in a Population of over 100 Million Commercially Insured Patients

Over the last decade there have been substantial changes in the availability of various forms of radiation therapy. The aim of our study was to better understand the changes in the use of radiation therapy among patients with prostate cancer, adults with other non-prostate cancer malignancies, and pediatric cancers. We specifically evaluated the changes in use of conventional radiation therapy (RT), 3D conformal radiation therapy (3DRT), intensity modulated radiation therapy (IMRT), stereotactic body radiation therapy (SBRT), and proton beam radiation therapy (PBRT) over a 10-year period in a commercially insured population. We conducted a retrospective analysis of data from the Optum Labs Data Warehouse (OLDW), an administrative claims database of privately insured and Medicare Advantage enrollees from throughout the US. The database contains data for over 100 million enrollees, from geographically diverse regions across the US. The plan provides fully insured coverage for professional (e.g., physician), facility (e.g., hospital), and outpatient prescription medication services. Descriptive analyses were undertaken to evaluate the utilization rates of radiation therapy from 2002-2012. From 2002 through 2012, 474 533 patients were treated with RT. The percent change in utilization per modality over the time period studied is shown in the table below. The most significant change in utilization occurred in the increase of utilization of IMRT for the treatment of prostate cancer, growing from 3.5% in 2002 to 64.0% by 2012. For non-prostate cancer in adults, IMRT adoption has demonstrated only modest growth. Proton beam radiation therapy utilization in adult patients remains very low. For children, its utilization has increased, but remains under 10% of cases treated in this population. For all patients, adoption of advanced technologies such as SBRT and PBRT has led to a combined utilization rate of less than 2% versus 22% for IMRT.Poster Viewing Abstracts 2891; TablePatient typeYearPBRT (%)SBRT (%)IMRT (%)3DRT (%)Other RT (%)All patients20020.10.02.134.563.4All patients20120.60.121.940.436.0Prostate20020.00.03.558.937.5Prostate20122.60.564.022.710.4Adult non-prostate20020.10.01.729.069.2Adult non-prostate20120.31.216.441.540.7Pediatric20020.30.03.529.167.1Pediatric20129.71.27.524.257.4 Open table in a new tab The introduction of SBRT and PBRT have had little impact on overall patterns of utilization and expenditure to date, in contrast to the shift in utilization seen after introduction of IMRT. The largest shift in utilization has occurred in the adoption of IMRT for prostate cancer for approximately two-thirds of adults with that diagnosis. Efforts to reduce costs in radiation oncology should focus on utilization patterns as well as the technological base used to deliver therapy.

Is There Justification for the Utilization of IMRT in the Treatment of Early-Stage Right Breast Cancer?

Intensity Modulated Radiation Therapy (IMRT) has been shown to reduce the heart dose in adjuvant radiation therapy for left breast cancer. However, the benefit of IMRT for right breast cancer has not been established and is therefore not routinely employed in clinical practice. The purpose of this study is to (1) compare dosimetric parameters in women with early stage right breast cancer undergoing whole breast radiation therapy using 3-dimensional conformal radiation (3DCRT) versus intensity modulated radiation therapy (IMRT) and (2) determine treatment planning and/or anatomical correlates for patients that may benefit from IMRT.

Intensity-modulated radiation therapy for head and neck cancer

Radiotherapy planning studies have confirmed dosimetric advantages of intensity-modulated radiation therapy over conventional and conformal radiation therapy. Utilization of intensity-modulated radiation therapy is ideal in head and neck cancer patients. Critical structures can be spared due to sharp dose gradients and limited organ motion with correct immobilization. Initial clinical results have shown excellent locoregional control, in part due to the delivery of high doses to the target volume. Reductions in acute toxicities and xerostomia through parotid sparing have been notable benefits. However, long-term outcomes with regards to local control and late toxicities with intensity-modulated radiation therapy are still lacking. This review focuses on the implementation of intensity-modulated radiation therapy for the treatment of head and neck cancers, with a specific focus on set-up uncertainties, dose prescription and target volume determination and delineation.

Novel strategies to improve target delineation for head and neck cancers

Novel strategies to improve target delineation for head and neck cancers

Novel strategies to improve target delineation for head and neck cancers

The need for a thorough knowledge base of head and neck anatomy as well as target and normal tissues (avoidance structures) delineation becomes more important with the increasing use of highly conformal radiotherapy such as intensity modulated radiation therapy (IMRT). Tools that facilitate easy identification of anatomical structures and spaces on axial CT images will not only improve target delineation but also encourage the full utilization of IMRT in radiotherapy centers. This study will develop and describe strategies to improve target delineation for head and neck cancers.