Outcomes of carotid-sparing IMRT for T1 glottic cancer: Comparison with conventional radiation

Stereotactic Ablative Radiotherapy for T1 to T2 Glottic Larynx Cancer: Mature Results From the Phase 2 GLoTtic Larynx-SABR Trial

PURPOSE

Traditional radiation therapy for early-stage larynx cancer irradiates the whole larynx over 5.5 to 6 weeks. Phase 1 data suggest that stereotactic ablative radiotherapy (SABR) is a viable strategy to reduce the irradiated volume and compress treatment time. This phase 2 study evaluated the efficacy of gLoTtic larynx-SABR in 5 or 16 fractions.

METHODS AND MATERIALS

Eligibility required stage 0 to II squamous cell carcinoma of the glottic larynx. The arytenoid cartilage could not be involved beyond the vocal process, and patients smoking more than one pack per day were excluded. The treatment volume consisted of the gross tumor volume, with a 3 mm margin (5 mm craniocaudal) to create the planning target volume. Patients without active smoking and planning target volume <10 cc received 4250 cGy in 5 fractions, twice per week; other patients received 58.08 Gy in 16 daily fractions. The primary endpoint was the 2-year incidence of local failure.

RESULTS

Twenty-five patients were accrued to this study, with 21 and 4 treated with 5 and 16 fractions, respectively. The stage distribution was in situ (n = 1, 4%), T1a/b (n = 16/5, 64%/20%), and T2 (n = 3, 12%). The median age was 72 years, with a prior smoking history in 16 (64%) and active smoking in 1 (4%). At a median follow-up for surviving patients of 3.7 years (IQR, 3.1-4.4 years), there have been 2 in-field recurrences (1 in each dose cohort). The cumulative incidences of local failure were 4% (90% CI, 0.8%-20%) and 8% (90% CI, 3%-24%) at 1 and 2 years, respectively. There have been no acute or late grade 3+ toxicities in disease-free patients. The median baseline, 1, 6, 12, and 24 months Voice Handicap Index scores were 57 (IQR, 32-69), 28.5 (8-48), 4 (0-12), 7.5 (0-12), and 5 (0-24), respectively.

CONCLUSIONS

Highly conformal stereotactic radiation therapy appears safe and efficacious for early-stage glottic larynx cancer, with encouraging patient-reported outcomes. These results need to be interpreted with caution given the small sample size and large noninferiority margin. Additional follow-up and ultimately comparative studies are necessary to validate this paradigm.

Stereotactic Radiation Therapy in 3 Fractions for T1 Glottic Cancer

PURPOSE/OBJECTIVE(S)

To report the results of a phases 1 and 2 study on stereotactic body radiation therapy (SBRT) for early glottic cancer.

METHODS AND MATERIALS

This a prospective study at a single institution enrolling patients with T1 glottic cancer. The true vocal cords (TVCs) were divided into thirds and the third(s) containing disease prescribed 36 Gy in 3 fractions. The portions of the TVCs next to the involved one were planned to receive 30 Gy in 3 fxs. SBRT was delivered by a linear accelerator-based approach using multiple arcs. Toxicity was scored by Common Terminology Criteria for Adverse Events and late events were considered those occurring 3 months after SBRT. Voice quality was investigated by the Voice Handicap Index at regular intervals. The planned sample size was 75 patients.

RESULTS

Accrual was discontinued after 33 patients because of concerns for late toxicity. T stage was as follows: T1a: 23 patients (69.7%); T1b: 10 patients (30.3%). All patients received the planned treatment and the median follow-up time was 51.5 months (IQR, 47.9-61.0 months). At last follow-up, all patients were alive and without evidence of disease but 2 patients who died for intercurrent causes. The local control rate was 100% at 4 years. Six patients (18.2%) developed soft tissue necrosis (N = 4) or cartilage necrosis (N = 2) after a median time of 14.9 months from SBRT. Five out of 6 necrotic events were observed in patients who kept smoking and/or had a recent COVID infection. All 4 soft tissue events healed with conservative therapy. After an initial deterioration, the average Voice Handicap Index score significantly improved at 6 months over baseline.

CONCLUSIONS

SBRT to 36 Gy in 3 fractions is highly effective in controlling T1 TVC carcinoma, but necrosis, although mostly transient, is a concern. On the basis of the present results, a reduction in total dose and a more accurate patient selection are warranted.

Patterns of Care for T1 Glottic Squamous Cell Carcinomas from 2004-2020

OBJECTIVE(S)

Describe recent national trends in overall treatment modalities for T1 glottic squamous cell carcinomas (SCC), and identify factors associated with treatment regimens.

METHODS

National Cancer Database from 2004-2020 was queried for all patients with glottic cT1N0M0 SCC. Treatment patterns over time were analyzed using the Cochran-Armitage test for trend. Multivariable logistic regressions were used to determine the factors associated with treatment regimens.

RESULTS

Of the 22,414 patients identified, most patients received RT only (57%), 21% received surgery only, and 22% received dual-modality treatment ("over-treatment"). Over the time period, there was a decreasing trend in rates of over-treatment for T1 glottic SCC (p < 0.001) and an increasing trend in surgery only (p < 0.001). Treatment in 2016-2018 (OR: 1.168 [1.004 to 1.359]), 2013-2015 (OR: 1.419 [1.221 to 1.648]), 2010-2012 (OR: 1.611 [1.388 to 1.871]), 2007-2009 (OR: 1.682 [1.450 to 1.951]), or 2004-2006 (OR: 1.795 [1.548 to 2.081]) versus 2019-2020 was associated with greater likelihood of over-treatment. T1b tumors were less likely to be over-treated (OR: 0.795 [0.707 to 0.894]) versus T1a tumors, and less likely to receive surgery first (OR: 0.536 [0.485 to 0.592]) versus T1a tumors.

CONCLUSION

Over-treatment for T1 glottic SCC has been declining, with increasing rates of surgery only. Year of treatment was significantly associated with the receipt of dual-modality treatment. Finally, patients with T1b disease were more likely to receive RT as the first and only treatment.

LEVEL OF EVIDENCE

3 Laryngoscope, 134:3633-3644, 2024.

Detection of Alteration in Carotid Artery Volumetry Using Standard-of-care Computed Tomography Surveillance Scans Following Unilateral Radiation Therapy for Early-stage Tonsillar Squamous Cell Carcinoma Survivors: A Cross-Sectional Internally-Matched Carotid Isodose Analysis

Purpose

Radiation induced carotid artery disease (RICAD) is a major cause of morbidity and mortality among survivors of oropharyngeal cancer. This study leveraged standard-of-care CT scans to detect volumetric changes in the carotid arteries of patients receiving unilateral radiotherapy (RT) for early tonsillar cancer, and to determine dose-response relationship between RT and carotid volume changes, which could serve as an early imaging marker of RICAD.

Methods and Materials

Disease-free cancer survivors (>3 months since therapy and age >18 years) treated with intensity modulated RT for early (T1-2, N0-2b) tonsillar cancer with pre- and post-therapy contrast-enhanced CT scans available were included. Patients treated with definitive surgery, bilateral RT, or additional RT before the post-RT CT scan were excluded. Pre- and post-treatment CTs were registered to the planning CT and dose grid. Isodose lines from treatment plans were projected onto both scans, facilitating the delineation of carotid artery subvolumes in 5 Gy increments (i.e. received 50-55 Gy, 55-60 Gy, etc.). The percent-change in sub-volumes across each dose range was statistically examined using the Wilcoxon rank-sum test.

Results

Among 46 patients analyzed, 72% received RT alone, 24% induction chemotherapy followed by RT, and 4% concurrent chemoradiation. The median interval from RT completion to the latest, post-RT CT scan was 43 months (IQR 32-57). A decrease in the volume of the irradiated carotid artery was observed in 78% of patients, while there was a statistically significant difference in mean %-change (±SD) between the total irradiated and spared carotid volumes (7.0±9.0 vs. +3.5±7.2, respectively, p<.0001). However, no significant dose-response trend was observed in the carotid artery volume change withing 5 Gy ranges (mean %-changes (±SD) for the 50-55, 55-60, 60-65, and 65-70+ Gy ranges [irradiated minus spared]: -13.1±14.7, -9.8±14.9, -6.9±16.2, -11.7±11.1, respectively). Notably, two patients (4%) had a cerebrovascular accident (CVA), both occurring in patients with a greater decrease in carotid artery volume in the irradiated vs the spared side.

Conclusions

Our data show that standard-of-care oncologic surveillance CT scans can effectively detect reductions in carotid volume following RT for oropharyngeal cancer. Changes were equivalent between studied dose ranges, denoting no further dose-response effect beyond 50 Gy. The clinical utility of carotid volume changes for risk stratification and CVA prediction warrants further evaluation.

Accelerated Fractionated Radiation Therapy for Localized Glottic Carcinoma

BACKGROUND

The aim of this study is to examine the outcomes of an accelerated fractionated irradiation for N0 glottic carcinoma.

METHODS

In this retrospective analysis, 29 patients with N0 glottic carcinoma treated by radiation therapy were enrolled. Thirteen patients had T1a disease, six had T1b disease, and ten had T2 disease. A fractional dose of 2.1 Gy was administered to seven patients. The total doses were 65.1 and 67.2 Gy in four and three patients, respectively. A fractional dose of 2.25 Gy was administered to 22 patients. The total doses were 63 and 67.5 Gy in 21 patients and 1 patient with T2 disease, respectively. Additionally, 13 patients underwent the use of TS-1 (80-100 mg per day).

RESULTS

The median follow-up period was 33 months, and the 3-year local control rate was 95.6%. No patient had a lymph node or distant recurrence. As acute adverse events, grades 2 and 3 dermatitis were observed in 18 patients and 1 patient, and grades 2 and 3 mucositis were observed in 15 patients and 1 patient. As a late adverse event, one patient required tracheotomy because of laryngeal edema occurring.

CONCLUSIONS

Accelerated fractionated irradiation may be an option in the radiation therapy of N0 glottic carcinoma because of its ability to shorten the treatment time.

Neurological complications of modern radiotherapy for head and neck cancer

Radiotherapy is one of the mainstay treatment modalities for the management of non-metastatic head and neck cancer (HNC). Notable improvements in treatment outcomes have been observed in the recent decades. Modern radiotherapy techniques, such as intensity-modulated radiotherapy and charged particle therapy, have significantly improved tumor target conformity and enabled better preservation of normal structures. However, because of the intricate anatomy of the head and neck region, multiple critical neurological structures such as the brain, brainstem, spinal cord, cranial nerves, nerve plexuses, autonomic pathways, brain vasculature, and neurosensory organs, are variably irradiated during treatment, particularly when tumor targets are in close proximity. Consequently, a diverse spectrum of late neurological sequelae may manifest in HNC survivors. These neurological complications commonly result in irreversible symptoms, impair patients' quality of life, and contribute to a substantial proportion of non-cancer deaths. Although the relationship between radiation dose and toxicity has not been fully elucidated for all complications, appropriate application of dosimetric constraints during radiotherapy planning may reduce their incidence. Vigilant surveillance during the course of survivorship also enables early detection and intervention. This article endeavors to provide a comprehensive review of the various neurological complications of modern radiotherapy for HNC, summarize the current incidence data, discuss methods to minimize their risks during radiotherapy planning, and highlight potential strategies for managing these debilitating toxicities.

Dosimetric comparison between carotid-sparing IMRT and 3DCRT in early glottic cancer patients treated with definitive radiation therapy

BACKGROUND

The purpose of this study was to evaluate the dosimetric benefits of carotid-sparing IMRT (intensity-modulated radiation therapy) over 3DCRT (three-dimensional conformal radiation therapy) in early glottic cancer patients.

MATERIAL AND METHODS

Ten patients with histologically proven early-stage squamous cell cancer of glottis (T1N0), treated with definitive radiotherapy, were selected retrospectively for the dosimetric analysis. Patients were originally treated with 3DCRT technique. For comparison purpose, IMRT plans were generated for each patient. Dosimetric comparison was done between two techniques (IMRT and 3DCRT) in terms of PTV (planning target volume) coverage, HI (homogeneity index), CI (conformity index), and doses to right carotid artery, left carotid artery, and spinal cord.

RESULTS

V95% for the PTV was higher in IMRT plans (98.26%) as compared to 3DCRT plans (95.12%) (P-value <0.001), whereas V105% for PTV was significantly higher in 3DCRT plans (16.77%) as compared to IMRT plans (0.32%) (P-value 0.11). In terms of both HI and CI, IMRT plans showed better conformity as compared to 3DCRT plans, with statistically significant difference. Both right and left carotid arteries' average mean and maximum doses were significantly lower in IMRT plans as compared to 3DCRT plans (P-value <0.001). IMRT plans resulted in significant carotid-sparing as compared to 3DCRT plans in terms of V35 and V50 (P-value <0.001).

CONCLUSION

Carotid-sparing IMRT resulted in better PTV coverage and lower carotid artery dose as compared to 3DCRT in early glottic cancer patients.

Intensity-Modulated Radiation Therapy for Early-Stage Squamous Cell Carcinoma of the Glottic Larynx: A Systematic Review and Meta-Analysis

PURPOSE

Early-stage squamous cell carcinoma of the glottic larynx is commonly treated with 2-dimensional or 3-dimensional conventional radiation therapy (CRT). Despite its use in other head and neck cancers, intensity-modulated radiation therapy (IMRT) remains controversial in this patient population.

METHODS AND MATERIALS

A systematic review was performed by querying 3 databases (Pubmed, Embase, Web of Science) for articles published between December 1, 2000 and September 2, 2022. Included studies reported outcomes in at least 10 patients treated with IMRT for early-stage glottic cancer. Data were extracted and reported following PRISMA standards. Pooled outcomes were estimated using random-effects models. Primary outcome was the rate of local failure (LF) following IMRT. Secondary outcomes included rates of regional failure (RF) following IMRT and rates of LF and RF following CRT.

RESULTS

A total of 15 studies (14 retrospective, 1 prospective) consisting of 2083 patients were identified. IMRT was used in 873 patients (64% T1, 28% T2). Multiple treatment (partial larynx, single vocal cord carotid sparing) and image-guided radiation therapy techniques were used. The pooled crude rate of LF was 7.6% (95% confidence inverval [CI], 3.6%-11.5%) and actuarial LF rates at 3 and 5 years were 6.3% (95% CI, 2.2%-10.3%) and 9.0% (95% CI, 4.4%-13.5%), respectively. The pooled crude rate of RF after IMRT was 1.5% (95% CI, 0.5%-2.5%). On metaregression analysis, increased rate of LF was significantly associated with T2 disease (P < .001) and grade 2 to 3 histology (P < .001). Treatment with CRT was reported in 738 patients (76% T1, 22% T2). Among the studies reporting outcomes of both modalities, there was no significant difference in LF (log odds ratio; P = .12) or RF (log odds ratio; P = .58) between IMRT or CRT.

CONCLUSIONS

In patients with early-stage glottic cancer, retrospective data suggests local and regional control are similar for patients treated with IMRT and CRT. Additional prospective studies with uniform methods of volume delineation and image guidance are needed to confirm the efficacy of IMRT.

Vertebral artery sparing volumetric modulated arc therapy in nasopharyngeal carcinoma

Vascular stenosis is a late radiation complication that develops in long-term survivors of nasopharyngeal carcinoma. Vertebral arteries (VAs) are major vessels responsible for posterior circulation. In this study, we evaluated the feasibility of VA-sparing volumetric modulated arc therapy (VMAT) techniques. A total of 20 patients with nasopharyngeal carcinoma treated by a TrueBeam linear accelerator were enrolled in this study. The original VMAT plan was designed without the contouring of VAs as organs at risk (OARs). The same image set of the original VMAT plan was used to contour the VAs for each patient. A new VA-sparing VMAT plan was developed by avoiding VAs as OARs. Finally, a paired t-test was used to compare the dosimetric differences. The VA-sparing VMAT plan had similar target coverage and dose to those of other OARs. The VA-sparing plan yielded a significantly low VA dose from 53 to 40 Gy, with V35Gy changing from 97% to 56%, V50Gy changing from 67% to 35%, and V63Gy changing from 15% to approximately 7%-10% (p < 0.001 for all comparisons). VAs should be correctly identified as OARs. Photon VMAT with VA sparing can help substantially decrease the VA dose.

Prognostic factors and a dynamic model on cancer-specific survival for T1a N0 M0 glottic cancer: A population-based analysis and clinical validation

OBJECTIVES

The survival rate varies tremendously in T_1a N₀ M₀ glottic cancer patients, which may be associated with the difference on patients' characters, such as age, treatment, and marital status. The objective of this study is to identify the vital factors and construct a dynamic prognostic model for predicting the cancer-specific survival (CSS) of patients with T_1a N₀ M₀ glottic cancer.

DESIGN, SETTING, AND PARTICIPANTS

The data of T_1a N₀ M₀ glottic cancer patients were extracted retrospectively from the SEER database between 2004 and 2015, which were randomly divided into the training dataset (70%) and the validation dataset (30%). The training cohort was used to identify independent prognostic factors and build the prognostic nomogram. While the validation cohort was used to validate the applicability of the newly constructed model.

MAIN OUTCOME MEASURES

The model was evaluated with the discrimination, the calibration, and the clinical benefit. The external data collecting from a medical center were used to validate the performance of the prognostic model.

RESULTS

Totally, 3286 eligible patients in the data of the SEER database and 139 eligible patients in our external clinical cohort were finally identified. 5 independent prognostic factors (age, marital status, Grade, primary site surgery, and chemotherapy) were identified and applied to develop the dynamic prognostic tool. C-indexes, receiver operating characteristic curves, calibration curves, and decision curve analyses proved that the prognostic nomogram showed excellent predictive accuracy, ability, and prognostic value. Using internal and external cohorts, the validation of the model also proved its reliability.

CONCLUSION

Prognostic factors for T_1a N₀ M₀ glottic cancer were identified. The novel web-based prognostic prediction tool may be beneficial in clinical decision-making and has value in risk stratification, personalized treatment, and clinical trial design.

Radiation for Early Glottic Cancer

Multidisciplinary evaluation of early-stage glottic cancer facilitates optimal treatment with either surgery or radiation therapy. Standard of care radiation treatment of early-stage glottic cancer continues to be three-dimensional opposed lateral fields to include the whole larynx. Modern radiation treatment techniques are allowing studies to examine the efficacy and toxicity of altered doses and treatment volumes. Advanced techniques, such as stereotactic body radiation therapy or single-vocal cord irradiation, are not yet considered standard of care for early-stage glottic cancer and should be performed at institutions with clinical trials to ensure adequate expertise and quality assurance.

Salvage surgery in laryngeal cancer after radiotherapy and partial surgery - comparative results

Objective

The study is a retrospective comparison of the usefulness of salvage surgery between a group of previously radiotherapy-treated patients (RTPs) and a group of patients who previously underwent partial surgery with both local and ± nodal recurrence.

Study Design

Retrospective study.

Setting

Multi-center academic hospital.

Materials and Methods

The former group was comprised 30 previously RTPs, whereas the latter group consisted of 20 patients after partial laryngeal surgery with optional subsequent adjuvant radiotherapy (PSPs). Treatment efficacy was compared in both groups in relation to overall survival (OS) and the locoregional control rate (LCR). Local and ± nodal recurrence was considered primary treatment failure. All patients underwent total laryngectomy.

Results

The updated 5-year OS in the PSPs was 31%, while the percentage of the updated 5-year LCR was 42%. In the RTPs the updated 5-year OS was 21%, and the percentage of 5-year LCR was 38%. No statistically significant differences were found in terms of the comparison of OS or the comparison of LCR results in both groups (P = 0.427, P = 0.704, respectively).

Conclusions

Based on the analysis, it was found that irrespective of the initial treatment, salvage surgery was associated with decreased survival and cure rates (by 50%) compared to the group of patients with advanced laryngeal cancer who underwent primary total laryngectomy.

Outcomes of carotid sparing intensity-modulated radiotherapy for early stage glottic cancer in 201 patients: Multicenter study of Turkish Radiation Oncology Society/TROD-01-007

BACKGROUND

To assess and report clinical outcomes after carotid sparing intensity-modulated radiotherapy for early stage laryngeal cancer.

METHODS

We retrospectively analyzed 201 patients with early stage glottic laryngeal cancer treated with carotid sparing intensity-modulated radiotherapy (IMRT)/volumetric modulated arc therapy (VMAT) techniques in six TROD centers.

RESULTS

After a median follow-up of 31 months the actuarial 1- and 3-year local and locoregional control rates were 99.4% and 94.7%, 98.4% and 93%, respectively. T classification, anterior commissure involvement, IMRT technique, and type of fractionation were not found to be prognostic for local control. Overall, eight patients had lost their organ function due to recurrence or toxicity. Grade 3 and 4 acute laryngeal edema was seen in eight (4%) and one (0.5%) of patients, respectively. Grade 3 and 4 late laryngeal edema developed in two (1%) and one patient (0.5%), respectively.

CONCLUSION

Oncologic outcomes of patients treated with carotid sparing IMRT were excellent; comparable with historical series, with acceptable side effects. Longer follow-up is needed to estimate long term effect on stroke.

Dysphagia, hypothyroidism, and osteoradionecrosis after radiation therapy for head and neck cancer

OBJECTIVES

To analyze the long-term side effects of radiation therapy (RT) for head and neck cancer (HNC).

METHODS

Retrospective chart analysis of all 688 HNC patients treated during 2010-2015 at Turku University Hospital, Finland. All patients who survived for more than a year after RT/chemoRT were included (n = 233). Intensity modulated RT (IMRT) with standard fractionation was applied in each case.

RESULTS

One hundred and six patients (45%) reported persisting dysphagia, for which neck RT increased risk. Definitive neck RT to high-risk volume did not increase late toxicity risks compared to elective neck RT. Radiation-induced hypothyroidism (29%, n = 67) was more common among younger patients and females. Osteoradionecrosis (12%, n = 29) was more common in the oral cavity cancer group (20.7%, n = 92) compared to all other subsites.

CONCLUSIONS

Late toxicities of RT for HNC are common. Age, gender, tumor subsite, and neck RT affect susceptibility to long-term side effects.

LEVEL OF EVIDENCE

4.

Early-Stage Glottic Squamous Cell Carcinoma in the Era of Image-Guided Radiotherapy

Early-stage squamous cell cancer (SCC) of the glottis has a good prognosis. Therefore, patients have long survival outcomes and may potentially suffer from late toxicities of radiotherapy. Radiotherapy with a conventional parallel-opposed-pair or anterior-oblique beam arrangements for stage 1 and 2 glottic SCC have field borders that traditionally cover the entire larynx, exposing organs-at-risk (e.g. carotid arteries, contralateral vocal cord, contralateral arytenoid and inferior pharyngeal constrictor muscles) to high radiation doses. The potential long-term risk of cerebrovascular events has attracted much attention to the dose that carotid arteries receive. Swallow and respiratory motion of laryngeal structures has been an important factor that previously limited reduction of the radiation treatment volume. Motion has been evaluated using multiple imaging modalities and this information has been used to calculate PTV margins for generation of more limited target volumes. This review discusses the current literature surrounding dose-effect relationships for various organs-at-risk and the late toxicities that are associated with them. This article also reviews the currently available data and effects of laryngeal motions on dosimetry to the primary target. We also review the current limitations and benefits of a more targeted approach of radiotherapy for early-stage glottic SCCs and the evolution of CT-based IGRT and MR-guided radiotherapy techniques that may facilitate a shift away from a conventional 3D-conformal radiotherapy approach.

Outcomes between intensity-modulated radiation therapy versus 3D-conformal in early stage glottic cancer

BACKGROUND

The purpose of this study is to evaluate practice patterns and outcomes between intensity-modulated radiation therapy (IMRT) and 3D-conformal radiation (3D-CRT) in early stage glottic cancer.

METHODS

The linked Surveillance, Epidemiology, and End Results (SEER)-Medicare database was used to identify and compare patient and disease profiles, mortality, and toxicity in patients with T1-2 larynx cancer undergoing definitive radiation (RT).

RESULTS

A total of 1520 patients underwent definitive radiation with 3D-CRT (n = 1309) or IMRT (n = 211). Non-white race, those with a Charlson Comorbidity Index ≥2, T2 disease, and those treated at community practices were more likely to undergo IMRT. Rates of IMRT increased from 2006 to 2015, while relative rates of 3D-CRT decreased. Two-year CSS was superior with 3D-CRT (hazard ratio [HR], 0.38; 95% confidence interval [CI], 0.22-0.65; p < 0.001). There was no difference in OS between 3D-CRT and IMRT (p = 0.119).

CONCLUSIONS

Patients receiving 3D-CRT had improved CSS compared to IMRT with no difference in OS.

Outcomes after radiation therapy for T2N0/stage II glottic squamous cell carcinoma

BACKGROUND

We report outcomes for patients with T2N0M0 glottic squamous cell carcinoma (SCC) treated with radiation therapy (RT).

METHODS

Patients who received definitive RT for T2 glottic SCC from 2000 through 2013 were retrospectively reviewed.

RESULTS

One hundred and thirteen patients were analyzed (median follow-up time 91 months; 85 patients received three-dimensional conformal radiotherapy [3D-CRT] and 28 received intensity-modulated radiation therapy [IMRT]). Fractionation was conventional (58%) or altered (42%); 20 patients (18%) received concurrent chemotherapy. Five-year local control was 83% for the 3D-CRT vs 81% for the IMRT group (P = .76). The ultimate locoregional control at 5 years was 100% for IMRT vs 91% for 3D-CRT (P = .1). The 5-year overall survival (OS) was 78% for 3D-CRT vs 81% for IMRT (P = .83). On multivariate analysis, younger age was the only independent predictor of improved OS (P = .0002).

CONCLUSIONS

Oncologic and survival outcomes were excellent for patients with T2N0 glottic cancer. Patients treated with IMRT and 3D-CRT had no statistically significant differences in all investigated endpoints.

Comparison of Three Fractionation Schedules in Radiotherapy for Early Glottic Squamous Cell Carcinoma

BACKGROUND/AIM

Radiotherapy is widely accepted as the treatment of choice for early glottic squamous cell carcinoma (EGSCC), although it varies greatly with respect to dose, dose per fraction, and treatment techniques. The study aim was to evaluate the use of accelerated fractionation strategy (AFS) for EGSCC in standard clinical practice.

PATIENTS AND METHODS

Patients treated with definitive radiotherapy for EGSCC between 2008 and 2019 were retrospectively identified and received either conventional fractionation, hypofractionation, or hyperfractionation.

RESULTS

One hundred six patients were analyzed, and 19, 71, and 16 patients underwent conventional fractionation, hypofractionation, and hyperfractionation, respectively. The median follow-up was 56 months. The 5-year local control and overall survival rates were 79% and 83%; 78% and 79%; and 87% and 77%, respectively, and no significant difference was observed between the fractionation schedules.

CONCLUSION

Our findings confirmed the utility of AFS in standard clinical practice and support its use for patients with EGSCC.

External validation of deep learning-based contouring of head and neck organs at risk

BACKGROUND AND PURPOSE

Head and neck (HN) radiotherapy can benefit from automatic delineation of tumor and surrounding organs because of the complex anatomy and the regular need for adaptation. The aim of this study was to assess the performance of a commercially available deep learning contouring (DLC) model on an external validation set.

MATERIALS AND METHODS

The CT-based DLC model, trained at the University Medical Center Groningen (UMCG), was applied to an independent set of 58 patients from the Radboud University Medical Center (RUMC). DLC results were compared to the RUMC manual reference using the Dice similarity coefficient (DSC) and 95th percentile of Hausdorff distance (HD95). Craniocaudal spatial information was added by calculating binned measures. In addition, a qualitative evaluation compared the acceptance of manual and DLC contours in both groups of observers.

RESULTS

Good correspondence was shown for the mandible (DSC 0.90; HD95 3.6 mm). Performance was reasonable for the glandular OARs, brainstem and oral cavity (DSC 0.78-0.85, HD95 3.7-7.3 mm). The other aerodigestive tract OARs showed only moderate agreement (DSC 0.53-0.65, HD95 around 9 mm). The binned measures displayed the largest deviations caudally and/or cranially.

CONCLUSIONS

This study demonstrates that the DLC model can provide a reasonable starting point for delineation when applied to an independent patient cohort. The qualitative evaluation did not reveal large differences in the interpretation of contouring guidelines between RUMC and UMCG observers.

Emerging Concepts and Novel Strategies in Radiation Therapy for Laryngeal Cancer Management

Laryngeal squamous cell carcinoma is the second most common head and neck cancer. Its pathogenesis is strongly associated with smoking. The management of this disease is challenging and mandates multidisciplinary care. Currently, accepted treatment modalities include surgery, radiation therapy, and chemotherapy—all focused on improving survival while preserving organ function. Despite changes in smoking patterns resulting in a declining incidence of laryngeal cancer, the overall outcomes for this disease have not improved in the recent past, likely due to changes in treatment patterns and treatment-related toxicities. Here, we review emerging concepts and novel strategies in the use of radiation therapy in the management of laryngeal squamous cell carcinoma that could improve the relationship between tumor control and normal tissue damage (therapeutic ratio).

Fractionation scheme and treatment planning method for early glottic cancer in the United States: Economic impact of different medical decisions

BACKGROUND

Early glottic cancers are often treated with radiotherapy (RT). We assessed the economic impact of fractionation scheme and planning method for payers in the United States.

METHODS

A population-based analysis of the total cost of RT for early glottic cancers in the United States was performed annually. The target population was calculated using the Surveillance, Epidemiology, and End Results database. RT costs were based on 2019 pricing by Medicare.

RESULTS

We estimate that 3794 patients with early glottic cancers are treated with RT annually. The cost of RT per patient ranges between US $13 964 and $26 599 by fractionation and planning method. Hypofractionation reduces costs by 9% to 14%, while Intensity-modulated radiotherapy (IMRT) increases costs by 65% to 72%. IMRT-based standard fractionation leads to an excess cost of $47 937 076 compared with 3D-based hypofractionation.

CONCLUSIONS

3D-based hypofractionated RT is the current standard of care. It would be reasonable for public and private payers to consider evidence-based policies for radiation reimbursement.

Preliminary Simulation Study of Carotid Artery and Pharyngeal Constrictor Muscle Sparing-Radiotherapy in Glottic Carcinoma

Background:

This preliminary simulation study aimed to compare the dosimetric outcomes of carotid arteries (CAs) and pharyngeal constrictor muscle (PCM) in patients with T1N0M0 glottic carcinoma undergoing helical tomotherapy-intensity modulated radiotherapy (HT-IMRT) and 3-dimensional conformal radiotherapy (3D-CRT) plans.

Methods:

In addition to the clinical target volume (CTV) which was defined as the entire larynx, the CAs and PCM of 11 glottic carcinoma patients were delineated. The CTV was uniformly expanded 5 mm to create a planning target volume (PTV) relative to the PCM and at a distance of 2 mm from the CA. The dosimetric characteristics in HT-IMRT and lateral opposed fields-based 3D-CRT plans were analyzed.

Results:

Median D_95%and V_100% of PTV were significantly higher in HT-IMRT (p < 0.001) compared to 3D-CRT. The right/left CA dosimetric outcomes, including the mean doses (20.7/21.5 Gy versus 48.7/50.5 Gy), D_max (53.6/52.0 Gy versus 67.4/67.7 Gy), V₃₀ (25.0/27.1% versus 77.6/80.3%), V₄₀ (8.0/7.9% versus 74.6/71.9%), and V₅₀ (2.0/1.2% versus 70.0/71.6%) were also significantly lower in HT-IMRT (p < 0.05), similar to the mean PCM doses (49.6 Gy versus 62.6 Gy for 3D-CRT;p < 0.001), respectively.

Conclusions:

Our present results demonstrated the feasibility of simultaneous sparing of the CAs and PCM in HT-IMRT- compared to 3D-CRT plans in glottic carcinoma patients undergoing definitive radiotherapy.

Patterns of Care and Outcomes of Intensity-Modulated Radiotherapy and 3D Conformal Radiotherapy for Early Stage Glottic Cancer: A National Cancer Database Analysis

Early stage glottic cancer has traditionally been treated with 3D conformal radiotherapy (3DCRT). However, intensity-modulated radiotherapy (IMRT) has been recently adopted as an alternative to decrease toxicity. Here, we compared the usage and outcomes of IMRT and 3DCRT for patients with early stage squamous cell carcinoma (SCC) of the glottic larynx. Using the National Cancer Database, we identified patients with Stage I–II SCC of the glottis who received 55–75 Gy using IMRT (n = 1623) or 3DCRT (n = 2696). Median follow up was 42 months with a 5-year overall survival (OS) of 72%. Using a nominal logistic regression, race, ethnicity, year of diagnosis and fraction size were associated with the receipt of IMRT (p < 0.05). Using Kaplan–Meier methods and Cox proportional hazards models as well as a propensity matched cohort, there was no difference in OS for patients who received IMRT versus 3DCRT (hazard ratio (HR), 1.08; 95% confidence interval (95% CI), 0.93–1.26; p = 0.302). However, there was a survival benefit for patients receiving slight hypofractionation as compared to conventional fractionation (HR, 0.78; 95% CI, 0.69–0.92; p = 0.003). IMRT was associated with similar survival as 3DCRT, supporting the implementation of this potentially less toxic modality without compromising survival.