Single Vocal Cord Irradiation: Image Guided Intensity Modulated Hypofractionated Radiation Therapy for T1a Glottic Cancer: Early Clinical Results

Stereotactic Radiotherapy in 3 fractions for T1 Glottic Cancer: SBRT in 3 fractions for early glottic cancer

PURPOSE/OBJECTIVE(S)

To report the results of a phase I-II study on SBRT for early glottic cancer.

MATERIALS/METHODS

This a prospective study at a single Institution enrolling patients with T1 glottic cancer. The true vocal cords (TVC) 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 LINAC-based approach using multiple arcs. Toxicity was scored by CTCAE and late events were considered those occurring 3 months after SBRT. Voice quality was investigated by the voice handicap index (VHI) at regular intervals. The planned sample size was 75 patients.

RESULTS

Accrual was discontinued after 33 patients due to concerns for late toxicity. T stage was as follows: T1a: 23 pts (69.7%); T1b: 10 pts (30.3%). All patients received the planned treatment and the median follow-up time is 51.5 months (IQR: 47.9-61.0 months). At last follow up, all patients are alive and without evidence of disease but two patients who died for intercurrent causes. The local control rate is 100% at 4 yrs. 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 VHI score significantly improved at 6 months over baseline.

CONCLUSION

SBRT to 36 Gy in 3 fractions is highly effective in controlling T1 TVC carcinoma, but necrosis, though mostly transient, is a concern. Based on the present results, a reduction in total dose as well as a more accurate patient selection are warranted.

Pencil Beam Scanning Proton Therapy as Single Vocal Cord Irradiation for Early-Stage Glottic Cancer

Purpose

Single vocal cord irradiation (SVCI) is a promising technique to maintain excellent oncologic control and potentially improve upon toxicities for treatment of early-stage glottic squamous cell carcinomas. We sought to investigate whether pencil beam scanning (PBS) proton therapy could improve upon the already favorable dose gradients demonstrated with volumetric modulated arc therapy (VMAT) SVCI.

Patients and Methods

A 64-year-old gentleman was treated in our department with 6X-flattening filter-free VMAT SVCI to 58.08 Gy in 16 fractions for a T1a well-differentiated squamous cell carcinoma of the left true vocal cord and tolerated it well with good local control. Comparative PBS plans were created in Raystation for the Varian ProBeam with clinical target volume (CTVs) generated to mimic the prescription target volume extent of the VMAT planning target volumes when accounting for PBS plan robustness (±3 mm translational shifts, 3.5% density perturbation). A 3-field single-field optimization plan was selected as dosimetrically preferable. Dosimetric variables were compared.

Results

Several organs at risk doses improved with PBS, including the maximum and mean dose to ipsilateral carotids, maximum and mean dose to contralateral carotid, maximum dose to the spinal cord, maximum and mean dose to inferior constrictor/cricopharyngeus, maximum and mean dose to the uninvolved vocal cord, and mean dose to the thyroid gland. There are tradeoffs in skin dose depending on location relative to the target-with the highest and lowest isodoses extending more into the skin with the VMAT plan but with the moderate isodose lines covering a wider area with the PBS plan, but we deemed it tolerable regardless.

Conclusion

SVCI is a promising strategy for maintaining the oncologic effectiveness of whole-larynx photon radiation while potentially improving upon the historic toxicity profile. The favorable dose distribution with PBS with respect to organs at risk dosimetry for PBS may allow for further improvements upon VMAT SVCI strategies. Clinical implementation of PBS SVCI may be considered.

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.

Nomogram for predicting survival in T1-T2 stage patients with supraglottic squamous cell carcinoma

BACKGROUND

Supraglottic squamous cell carcinoma (SGSCC) is characterized by low differentiation, rapid growth, and inconspicuous initial manifestations. Early detection and prompt treatment can significantly improve survival rates. The main focus of treatment is to maintain optimal laryngeal function.

METHODS

Using the Surveillance, Epidemiology, and End Results (SEER) database, we conducted univariate and multivariate Cox regression analyses to identify independent prognostic factors for T1-T2 SGSCC. We also enrolled 109 patients with T1-T2 SGSCC from the First Affiliated Hospital of Xinjiang Medical University as an external validation set. In addition, we developed a nomogram to predict the prognosis of T1-T2 SGSCC, assessed the predictive accuracy and discriminatory ability of the nomogram using the area under the curve (AUC), C-index, receiver operating characteristic (ROC) curve and calibration curve, and confirmed the clinical validity of the nomogram using decision curve analysis (DCA).

RESULTS

Our investigation identified nine prognostic indicators for T1-T2 SGSCC: age (≥ 65 years), marital status, American Joint Committee on Cancer (AJCC) stage (II-IV), grade (III-IV), M stage (M1), radiotherapy, chemotherapy, sex (female), and surgery. These variables were used to create accurate nomograms that predict overall and specific survival rates at 1, 3, and 5 years. The nomograms demonstrated superior prognostic value and accuracy compared to AJCC staging. Laryngectomy with partial laryngectomy is the preferred treatment option for T1-T2 SGSCC cases, providing superior overall survival (OS) and cancer-specific survival (CSS). Radiotherapy also improves OS and CSS. Our results were based on a comprehensive analysis of various indicators, including the C-index, ROC curve, calibration curve, and DCA curve.

CONCLUSION

Nomograms provide significant advantages in treatment decision making and diagnosis. Laryngectomy with partial laryngectomy is the most appropriate method for T1-T2 SGSCC cases. However, radiotherapy can also be used. Thus, patients with T1-T2 SGSCC should be evaluated to determine if combination therapy is the optimal treatment approach. Nevertheless, further research is needed to understand the role of chemotherapy. Overall, this study identified nine key predictors of future outcomes, aiding healthcare professionals in assessing risks and making treatment decisions for T1-T2 SGSCC patients.

Assessment and validation of glottic motion using cone-beam CT and real-time cine MRI

PURPOSE

This study aimed to assess the margin for the planning target volume (PTV) using the Van Herk formula. We then validated the proposed margin by real-time magnetic resonance imaging (MRI).

METHODS

An analysis of cone-beam computed tomography (CBCT) data from early glottic cancer patients was performed to evaluate organ motion. Deformed clinical target volumes (CTV) after rigid registration were acquired using the Velocity program (Varian Medical Systems, Palo Alto, CA, USA). Systematic (Σ) and random errors (σ) were evaluated. The margin for the PTV was defined as 2.5 Σ + 0.7 σ according to the Van Herk formula. To validate this margin, we accrued healthy volunteers. Sagittal real-time cine MRI was conducted using the ViewRay system (ViewRay Inc., Oakwood Village, OH, USA). Within the obtained sagittal images, the vocal cord was delineated. The movement of the vocal cord was summed up and considered as the internal target volume (ITV). We then assessed the degree of overlap between the ITV and the PTV (vocal cord plus margins) by calculating the volume overlap ratio, represented as (ITV∩PTV)/ITV.

RESULTS

CBCTs of 17 early glottic patients were analyzed. Σ and σ were 0.55 and 0.57 for left-right (LR), 0.70 and 0.60 for anterior-posterior (AP), and 1.84 and 1.04 for superior-inferior (SI), respectively. The calculated margin was 1.8 mm (LR), 2.2 mm (AP), and 5.3 mm (SI). Four healthy volunteers participated for validation. A margin of 3 mm (AP) and 5 mm (SI) was applied to the vocal cord as the PTV. The average volume overlap ratio between ITV and PTV was 0.92 (range 0.85-0.99) without swallowing and 0.77 (range 0.70-0.88) with swallowing.

CONCLUSION

By evaluating organ motion by using CBCT, the margin was 1.8 (LR), 2.2 (AP), and 5.3 mm (SI). The margin acquired using CBCT fitted well in real-time cine MRI. Given that swallowing during radiotherapy can result in a substantial displacement, it is crucial to consider strategies aimed at minimizing swallowing and related motion.

Individualized Dynamic Prediction Model for Patient-Reported Voice Quality in Early-Stage Glottic Cancer

OBJECTIVE

Early-stage glottic cancer (ESGC) is a malignancy of the head and neck. Besides disease control, preservation and improvement of voice quality are essential. To enable expectation management and well-informed decision-making, patients should be sufficiently counseled with individualized information on expected voice quality. This study aims to develop an individualized dynamic prediction model for patient-reported voice quality. This model should be able to provide individualized predictions at every time point from intake to the end of follow-up.

STUDY DESIGN

Longitudinal cohort study.

SETTING

Tertiary cancer center.

METHODS

Patients treated for ESGC were included in this study (N = 294). The Voice Handicap Index was obtained prospectively. The framework of mixed and joint models was used. The prognostic factors used are treatment, age, gender, comorbidity, performance score, smoking, T-stage, and involvement of the anterior commissure. The overall performance of these models was assessed during an internal cross-validation procedure and presentation of absolute errors using box plots.

RESULTS

The mean age in this cohort was 67 years and 81.3% are male. Patients were treated with transoral CO2 laser microsurgery (57.8%), single vocal cord irradiation up to (24.5), or local radiotherapy (17.5%). The mean follow-up was 43.4 months (SD 21.5). Including more measurements during prediction improves predictive performance. Including more clinical and demographic variables did not provide better predictions. Little differences in predictive performance between models were found.

CONCLUSION

We developed a dynamic individualized prediction model for patient-reported voice quality. This model has the potential to empower patients and professionals in making well-informed decisions and enables tailor-made counseling.

Accounting for fractionation and heterogeneous dose distributions in the modelling of osteoradionecrosis in oropharyngeal carcinoma treatment

BACKGROUND AND PURPOSE

Osteoradionecrosis (ORN) of the mandible is a severe complication following radiotherapy (RT). With a renewed interest in hypofractionation for head and neck radiotherapy, more information concerning ORN development after high fraction doses is important. The aim of this explorative study was to develop a model for ORN risk prediction applicable across different fractionation schemes using Equivalent Uniform Doses (EUD).

MATERIAL AND METHODS

We performed a retrospective cohort study in 334 oropharyngeal squamous cell carcinoma (OPSCC) patients treated with either a hypofractionated Stereotactic Body Radiation Therapy (HF-SBRT) boost or conventional Intensity Modulated Radiation Therapy (IMRT). ORN was scored with the CTCAE v5.0. HF-SBRT and IMRT dose distributions were converted into equivalent dose in 2 Gy fractions (α/β = 0.85 Gy) and analyzed using EUD. The parameter a that led to an EUD that best discriminated patients with and without grade ≥ 2 ORN was selected. Patient and treatment-related risk factors of ORN were analyzed with uni- and multivariable regression analysis.

RESULTS

A total of 32 patients (9.6%) developed ORN grade ≥ 2. An EUD(a = 8) best discriminated between ORN and non-ORN (AUC = 0.71). In multivariable regression, pre-RT extractions (SHR = 2.34; p = 0.012), mandibular volume (SHR = 1.04; p = 0.003), and the EUD(a = 8) (SHR = 1.14; p < 0.001) were significantly associated with ORN.

CONCLUSION

Risk models for ORN based on conventional DVH parameters cannot be directly applied to HF-SBRT fractionation schemes and dose distributions. However, after correcting for fractionation and non-uniform dose distributions using EUD, a single model can distinguish between ORN and non-ORN after conventionally fractionated radiotherapy and hypofractionated boost treatments.

Salvage transoral laser microsurgery for early local recurrence of glottic squamous cell cancer

BACKGROUND

For recurrent laryngeal cancer, the feasibility of salvage transoral laser microsurgery (TLM) remains controversial. This study compared the efficacy of TLM and open partial laryngectomy (OPL) for treatment of early local recurrence of glottic squamous cell cancer (GSCC) and confirm the effectiveness of salvage TLM as a treatment option.

METHODS

This retrospective study involved 55 patients with early local recurrent GSCC treated with TLM, and the oncologic outcomes, functional outcomes, hospitalization time and complications were compared with a group of 40 recurrent GSCC patients matched for clinical variables of TLM group, treated by OPL by the same team of surgeons.

RESULTS

The 5-year overall survival and disease-specific survival rates were 65.8% and 91.5%, respectively, for 55 patients with rT_is-rT₂ stage treated by TLM and 77.1% and 94.7%, respectively, for 40 patients with rT_is-rT₂ stage treated by OPL (OPL group). In the TLM and OPL groups, the local control rates after 5 years were 77.5% and 79.3%, respectively, and the laryngeal preservation rates were 94.4% and 83.6%, respectively (p > 0.05). Compared with the OPL group, the complication rate (1.82%) and hospitalization duration (5.42 ± 2.26 days) were significantly lower in the TLM group (p < 0.05). Compared with the OPL group, postsurgical health-related quality of life and quality of voice were significantly better in the TLM group (p < 0.001).

CONCLUSION

Salvage TLM can be used as an effective treatment option for suitable patients after a full, comprehensive, and careful assessment of the characteristics of early locally recurrent glottic carcinoma.

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.

Longitudinal Patient-Reported Voice Quality in Early-Stage Glottic Cancer

OBJECTIVE

Patient-reported voice quality is an important outcome during counseling in early-stage glottic cancer. However, there is a paucity of adequate longitudinal studies concerning voice outcomes. This study aimed to investigate longitudinal trajectories for patient-reported voice quality and associated risk factors for treatment modalities such as transoral CO₂ laser microsurgery, single vocal cord irradiation, and local radiotherapy.

STUDY DESIGN

A longitudinal observational cohort study.

SETTING

Tertiary cancer center.

METHODS

Patients treated for Tcis-T1b, N0M0 glottic cancer were included in this study (N = 294). The Voice Handicap Index was obtained at baseline and during follow-up (N = 1944). Mixed-effects models were used for investigating the different trajectories for patient-reported voice quality.

RESULTS

The mean follow-up duration was 43.4 (SD 21.5) months. Patients received transoral CO₂ laser microsurgery (57.8%), single vocal cord irradiation (24.5%), or local radiotherapy (17.5%). A steeper improvement during the first year after treatment for single vocal cord irradiation (-15.7) and local radiotherapy (-12.4) was seen, compared with a more stable trajectory for laser surgery (-6.1). All treatment modalities showed equivalent outcomes during long-term follow-up. Associated risk factors for different longitudinal trajectories were age, tumor stage, and comorbidity.

CONCLUSION

Longitudinal patient-reported voice quality after treatment for early-stage glottic cancer is heterogeneous and nonlinear. Most improvement is seen during the first year of follow-up and differs between treatment modalities. No clinically significant differences in long-term trajectories were found. Insight into longitudinal trajectories can enhance individual patient counseling and provide the foundation for an individualized dynamic prediction model.

Post radiation mucosal ulcer risk after a hypofractionated stereotactic boost and conventional fractionated radiotherapy for oropharyngeal carcinoma

BACKGROUND/PURPOSE

Post radiation mucosal ulcers (PRMU) after treatment for oropharyngeal squamous cell carcinoma (OPSCC) can have a huge negative impact on patients' quality of life, but little is known concerning risk factors and the impact of fraction size. Therefore, the goal of this study was to determine the pattern of PRMU development and to identify risk factors after a hypofractionated stereotactic body radiotherapy boost (SBRT) compared to conventionally fractionated radiotherapy for OPSCC.

MATERIAL AND METHODS

We performed a retrospective cohort study (N = 332) of OPSCC patients with ≥ 1-year disease-free survival, treated with 46 Gy Intensity Modulated Radiotherapy (IMRT) (2 Gy fractions) followed by either an SBRT boost of 16.5 Gy (5.5 Gy fractions) (N = 180), or 24 Gy IMRT (2 Gy fractions) (N = 152). PRMU (grade ≥ 2) was scored when observed > three months after the last radiotherapy (RT) fraction (CTCAE v5.0). Potential risk factors were analyzed with Cox regression models using death as competing risk. Dose at the PRMU site was calculated by projecting delineated PRMU on the planning CT.

RESULTS

All cases of PRMU (N = 64) occurred within 24 months; all were grade 2. The cumulative incidence at 2 years in the SBRT boost group was 26% (N = 46) vs. 12% (N = 18) for conventional fractionation (p = 0.003). Most PRMU developed within nine months (N = 48). PRMU occurring > nine months (N = 16) were mainly observed in the SBRT boost group (N = 15). Sex (p = 0.048), acute tube feeding (p = < 0.001), tumor subsite tonsil (p = 0.001), and N stage (p = 0.017) were associated with PRMU risk at multivariable regression in the hypofractionated SBRT boost group. All 25 delineated PRMU were located within the high dose regions.

CONCLUSION

The risk of PRMU should be included in the cost benefit analysis when considering future research using a hypofractionated SBRT boost for OPSCC patients.

Intensity modulated proton therapy for early-stage glottic cancer: high-precision approach to laryngeal function preservation with exceptional treatment tolerability

BACKGROUND

Due to the increasing expertise in transoral laser surgery and image-guided radiation therapy, treatment outcomes have recently improved in patients with early-stage glottic cancer. The objective of the current study was to evaluate intensity-modulated proton therapy (IMPT) as novel treatment option.

METHODS

A total of 15 patients with T1-2N0 glottic squamous cell carcinoma, treated between 2017 and 2020, were evaluated. Toxicity was recorded according to the Common Terminology Criteria for Adverse Events (CTCAE) v4.03.

RESULTS

The majority were T1a/b tumors (66.7%) and no patient had lymph node or distant metastases. The median total dose was 70 Gy relative biological effectiveness (RBE) (range 66-70 Gy RBE). The one- and two-year OS and metastases-free survival were 100%. One patient developed local failure and received salvage laryngectomy. No higher-grade acute or late toxicity was reported. The mean number of CTCAE grade I and II overall toxicity events per patient was 4.1 (95%-[confidence interval] CI 3.1-5.3) and 1.0 (95%-CI 0.5-1.5).

CONCLUSION

High-precision proton therapy of T1-2N0 glottic cancer resulted in exceptional treatment tolerability with high rates of laryngeal function preservation and promising oncological outcome. IMPT has the potential to become a standard treatment option for patients with early-stage laryngeal cancer.

VoiceS: voice quality after transoral CO2 laser surgery versus single vocal cord irradiation for unilateral stage 0 and I glottic larynx cancer-a randomized phase III trial

Background

Surgery and radiotherapy are well-established standards of care for unilateral stage 0 and I early-stage glottic cancer (ESGC). Based on comparative studies and meta-analyses, functional and oncological outcomes after both treatment modalities are similar. Historically, radiotherapy (RT) has been performed by irradiation of the whole larynx. However, only the involved vocal cord is being treated with recently introduced hypofractionated concepts that result in 8 to 10-fold smaller target volumes. Retrospective data argues for an improvement in voice quality with non-inferior local control. Based on these findings, single vocal cord irradiation (SVCI) has been implemented as a routine approach in some institutions for ESGC in recent years. However, prospective data directly comparing SVCI with surgery is lacking. The aim of VoiceS is to fill this gap.

Methods

In this prospective randomized multi-center open-label phase III study with a superiority design, 34 patients with histopathologically confirmed, untreated, unilateral stage 0-I ESGC (unilateral cTis or cT1a) will be randomized to SVCI or transoral CO₂-laser microsurgical cordectomy (TLM). Average difference in voice quality, measured by using the voice handicap index (VHI) will be modeled over four time points (6, 12, 18, and 24 months). Primary endpoint of this study will be the patient-reported subjective voice quality between 6 to 24 months after randomization. Secondary endpoints will include perceptual impression of the voice via roughness – breathiness – hoarseness (RBH) assessment at the above-mentioned time points. Additionally, quantitative characteristics of voice, loco-regional tumor control at 2 and 5 years, and treatment toxicity at 2 and 5 years based on CTCAE v.5.0 will be reported.

Discussion

To our knowledge, VoiceS is the first randomized phase III trial comparing SVCI with TLM. Results of this study may lead to improved decision-making in the treatment of ESGC.

Trial registration

ClinicalTrials.gov NCT04057209. Registered on 15 August 2019. Cantonal Ethics Committee KEK-BE 2019-01506

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-022-06841-5.

Organ-at-risk sparing with dynamic trajectory radiotherapy for head and neck cancer: comparison with volumetric arc therapy on a publicly available library of cases

Background

Dynamic trajectory radiotherapy (DTRT) extends volumetric modulated arc therapy (VMAT) with dynamic table and collimator rotation during beam-on. The aim of the study is to establish DTRT path-finding strategies, demonstrate deliverability and dosimetric accuracy and compare DTRT to state-of-the-art VMAT for common head and neck (HN) cancer cases.

Methods

A publicly available library of seven HN cases was created on an anthropomorphic phantom with all relevant organs-at-risk (OARs) delineated. DTRT plans were generated with beam incidences minimizing fractional target/OAR volume overlap and compared to VMAT. Deliverability and dosimetric validation was carried out on the phantom.

Results

DTRT and VMAT had similar target coverage. For three locoregionally advanced oropharyngeal carcinomas and one adenoid cystic carcinoma, mean dose to the contralateral salivary glands, pharynx and oral cavity was reduced by 2.5, 1.7 and 3.1 Gy respectively on average with DTRT compared to VMAT. For a locally recurrent nasopharyngeal carcinoma, D_0.03 cc to the ipsilateral optic nerve was above tolerance (54.0 Gy) for VMAT (54.8 Gy) but within tolerance for DTRT (53.3 Gy). For a laryngeal carcinoma, DTRT resulted in higher dose than VMAT to the pharynx and brachial plexus but lower dose to the upper oesophagus, thyroid gland and contralateral carotid artery. For a single vocal cord irradiation case, DTRT spared most OARs better than VMAT. All plans were delivered successfully on the phantom and dosimetric validation resulted in gamma passing rates of 93.9% and 95.8% (2%/2 mm criteria, 10% dose threshold).

Conclusions

This study provides a proof of principle of DTRT for common HN cases with plans that were deliverable on a C-arm linac with high accuracy. The comparison with VMAT indicates substantial OAR sparing could be achieved.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13014-022-02092-5.

Target Definition in MR-Guided Adaptive Radiotherapy for Head and Neck Cancer

In recent years, MRI-guided radiotherapy (MRgRT) has taken an increasingly important position in image-guided radiotherapy (IGRT). Magnetic resonance imaging (MRI) offers superior soft tissue contrast in anatomical imaging compared to computed tomography (CT), but also provides functional and dynamic information with selected sequences. Due to these benefits, in current clinical practice, MRI is already used for target delineation and response assessment in patients with head and neck squamous cell carcinoma (HNSCC). Because of the close proximity of target areas and radiosensitive organs at risk (OARs) during HNSCC treatment, MRgRT could provide a more accurate treatment in which OARs receive less radiation dose. With the introduction of several new radiotherapy techniques (i.e., adaptive MRgRT, proton therapy, adaptive cone beam computed tomography (CBCT) RT, (daily) adaptive radiotherapy ensures radiation dose is accurately delivered to the target areas. With the integration of a daily adaptive workflow, interfraction changes have become visible, which allows regular and fast adaptation of target areas. In proton therapy, adaptation is even more important in order to obtain high quality dosimetry, due to its susceptibility for density differences in relation to the range uncertainty of the protons. The question is which adaptations during radiotherapy treatment are oncology safe and at the same time provide better sparing of OARs. For an optimal use of all these new tools there is an urgent need for an update of the target definitions in case of adaptive treatment for HNSCC. This review will provide current state of evidence regarding adaptive target definition using MR during radiotherapy for HNSCC. Additionally, future perspectives for adaptive MR-guided radiotherapy will be discussed.

Single vocal cord irradiation for early-stage glottic cancer: Excellent local control and favorable toxicity profile

OBJECTIVE

To validate the earlier reported promising oncologic outcomes and favorable toxicity profile following single vocal cord irradiation (SVCI) in an expanded cohort of patients with early-stage glottic cancer treated at our institute with longer follow-up time.

MATERIALS AND METHODS

Between February 2011 and January 2020, 111 consecutive patients with early-stage glottic cancer were treated with SVCI to the whole involved vocal cord (58.08 Gy, given in 16 fractions of 3.63 Gy). Setup verification was done using cone-beam CT, prior to each fraction. The endpoints were local control (LC), overall survival (OS), grade ≥ 3 toxicity and voice quality assessment using voice-handicap index (VHI) questionnaires.

RESULTS

Median follow-up was 41 months (range; 8-84). Two patients developed in-field local failure (LF). The 3- and 5-year LC rates were 99.1% and 97.1%, respectively. As both patients with LF were successfully salvaged with total laryngectomy, the 5-year ultimate LC-rates was 99%. The 5-years OS was 80.6%. All patients finished treatment without any interruption. No patients developed acute grade ≥ 3 toxicity. Late grade 3 toxicity was reported in 7 patients (6.5%) out of 108 patients evaluable for late toxicity; 2 because of severe hoarseness and 5 because of laryngeal radionecrosis (4.5%). The 5-years laryngectomy-free survival was 98.1%. The VHI-scores improved over time, only 22% of patients had VHI > 30 at 3-years post-radiotherapy, compared to 38% at baseline.

CONCLUSIONS

Local control rate and laryngectomy-free survival of SVCI are excellent with favorable toxicity profile and good VHI-score. These results validate our early results.

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.

Reduction of GTV to high-risk CTV radiation margin in head and neck squamous cell carcinoma significantly reduced acute and late radiation-related toxicity with comparable outcomes

BACKGROUND AND PURPOSE

We aim to retrospectively investigate whether reducing GTV to high-risk CTV margin will significantly reduce acute and late toxicity without jeopardizing outcome in head-and-neck squamous cell carcinoma (HNSCC) treated with definitive (chemo)radiation.

MATERIALS AND METHODS

Between April 2015 and April 2019, 155 consecutive patients were treated with GTV to high-risk CTV margin of 10 mm and subsequently another 155 patients with 6 mm margin. The CTV-PTV margin was 3 mm for both groups. All patients were treated with volumetric-modulated arc therapy with daily image-guidance using cone-beam CT. End points of the study were acute and late toxicity and oncologic outcomes.

RESULTS

Overall acute grade 3 toxicity was significantly lower in 6 mm, compared to 10 mm group (48% vs. 67%, respectively, p < 0.01). The same was true for acute grade 3 mucositis (18% vs. 34%, p < 0.01) and grade ≥ 2 dysphagia (67% vs. 85%, p < 0.01). Also feeding tube-dependency at the end of treatment (25% vs. 37%, p = 0.02), at 3 months (12% and 25%, p < 0.01), and at 6 months (6% and 15%, p = 0.01) was significantly less in 6 mm group. The incidence of late grade 2 xerostomia was also significantly lower in the 6 mm group (32% vs. 50%, p < 0.01). The 2-year rates of loco-regional control, disease-free and overall survival were 78.7% vs. 73.1%, 70.6% vs. 61.4%, and 83.2% vs. 74.4% (p > 0.05, all).

CONCLUSION

The first study reporting on reduction of GTV to high-risk CTV margin from 10 to 6 mm showed significant reduction of the incidence and severity of radiation-related toxicity without reducing local-regional control and survival.

Organ motion in linac-based SBRT for glottic cancer

Purpose

The purpose of this study is to evaluate inter- and intra-fraction organ motion as well as to quantify clinical target volume (CTV) to planning target volume (PTV) margins to be adopted in the stereotactic treatment of early stage glottic cancer.

Methods and materials

Stereotactic body radiotherapy (SBRT) to 36 Gy in 3 fractions was administered to 23 patients with early glottic cancer T1N0M0. Patients were irradiated with a volumetric intensity modulated arc technique delivered with 6 MV FFF energy. Each patient underwent a pre-treatment cone beam computed tomography (CBCT) to correct the setup based on the thyroid cartilage position. Imaging was repeated if displacement exceeded 2 mm in any direction. CBCT imaging was also performed after each treatment arc as well as at the end of the delivery. Swallowing was allowed only during the beam-off time between arcs. CBCT images were reviewed to evaluate inter- and intra-fraction organ motion. The relationships between selected treatment characteristics, both beam-on and delivery times as well as organ motion were investigated.

Results

For the population systematic (Ʃ) and random (σ) inter-fraction errors were 0.9, 1.3 and 0.6 mm and 1.1, 1.3 and 0.7 mm in the left-right (X), cranio-caudal (Y) and antero-posterior (Z) directions, respectively. From the analysis of CBCT images acquired after treatment, systematic (Ʃ) and random (σ) intra-fraction errors resulted 0.7, 1.6 and 0.7 mm and 1.0, 1.5 and 0.6 mm in the X, Y and Z directions, respectively. Margins calculated from the intra-fraction errors were 2.4, 5.1 and 2.2 mm in the X, Y and Z directions respectively. A statistically significant difference was found for the displacement in the Z direction between patients irradiated with > 2 arcs versus ≤ 2 arcs, (MW test, p = 0.038). When analyzing mean data from CBCT images for the whole treatment, a significant correlation was found between the time of delivery and the three dimensional displacement vector (r = 0.489, p = 0.055), the displacement in the Y direction (r = 0.553, p = 0.026) and the subsequent margins to be adopted (r = 0.626, p = 0.009). Finally, displacements and the subsequent margins to be adopted in Y direction were significantly greater for treatments with more than 2 arcs (MW test p = 0.037 and p = 0.019, respectively).

Conclusions

In the setting of controlled swallowing during treatment delivery, intra-fraction motion still needs to be taken into account when planning with estimated CTV to PTV margins of 3, 5 and 3 mm in the X, Y and Z directions, respectively. Selected treatments may require additional margins.

[Radiotherapy for patients with early-stage glottic squamous cell carcinoma of the larynx: Interest of hypofractionation?]

Hypofractionated radiotherapy of early-stage squamous cell carcinoma of the glottic larynx is a promising treatment option. This can be divided into radiotherapy with moderate hypofractionation (up to 2.5Gy per fraction), more intense hypofractionation (between 2.5 and 4.5Gy per fraction) and stereotactic radiotherapy (above 4.5Gy per fraction). Most studies evaluating moderate hypofractionation show a local control rate between 85 and 95%. Acute laryngeal toxicity is superior to conventional treatment, but only for grades 1 and 2, with no significant difference reported for severe toxicity. Stereotactic radiotherapy in this pathology is also an emerging entity, but some authors have reported significant toxicity. There are currently no standardized guidelines for treatment and management regimen. We conducted a systemic review of published prospective and retrospective trials to evaluate efficacy, toxicity, and discuss future directions.

Vocal-cord Only vs. Complete Laryngeal radiation (VOCAL): a randomized multicentric Bayesian phase II trial

BACKGROUND

Radiotherapy, along with laser surgery, is considered a standard treatment option for patients with early glottic squamous cell cancer (SCC). Historically, patients have received complete larynx radiotherapy (CL-RT) due to fear of swallowing and respiratory laryngeal motion and this remains the standard approach in many academic institutions. Local control (LC) rates with CL-RT have been excellent, however this treatment can carry significant toxicities include adverse voice and swallowing outcomes, along with increased long-term risk of cerebrovascular morbidity. A recent retrospective study reported improved voice quality and similar local control outcomes with focused vocal cord radiotherapy (VC-RT) compared to CL-RT. There is currently no prospective evidence on the safety of VC-RT. The primary objective of this Bayesian Phase II trial is to compare the LC of VC-RT to that of CL-RT in patients with T1N0 glottic SCC.

METHODS

One hundred and fifty-five patients with T1a-b N0 SCC of the true vocal cords that are n ot candidate or declined laser surgery, will be randomized in a 1:3 ratio the control arm (CL-RT) and the experimental arm (VC-RT). Randomisation will be stratified by tumor stage (T1a/T1b) and by site (each site will be allowed to select one preferred radiation dose regimen, to be used in both arms). CL-RT volumes will correspond to the conventional RT volumes, with the planning target volume extending from the top of thyroid cartilage lamina superiorly to the bottom of the cricoid inferiorly. VC-RT volumes will include the involved vocal cord(s) and a margin accounting for respiration and set-up uncertainty. The primary endpoint will be LC at 2-years, while secondary endpoints will include patient-reported outcomes (voice impairment, dysphagia and symptom burden), acute and late toxicity radiation-induced toxicity, overall survival, progression free survival, as well as an optional component of acoustic and objective measures of voice analysis using the Consensus Auditory-Perceptual Evaluation of Voice.

DISCUSSION

This study would constitute the first prospective evidence on the efficacy and safety of VC-RT in early glottic cancer. If positive, this study would result in the adoption of VC-RT as standard approach in early glottic cancer.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03759431 Registration date: November 30, 2018.

Stereotactic body radiotherapy for T1 glottic cancer: dosimetric data in 27 consecutive patients

AIM

Because the clinical feasibility of stereotactic body radiotherapy (SBRT) for early glottic cancer (T1) is controversial, we report dosimetric results in 27 consecutive patients from a prospective phase I and II study that started in 2017.

METHODS

In our approach, only the parts of the true vocal cord containing cancer and those immediately adjacent are planned to be treated to 36 Gy and 30 Gy, respectively, in 3 fractions. Several dosimetric metrics for both target volumes and organs at risk were extracted from individual plans and results were compared to those achieved by other authors in a similar setting.

RESULTS

Proper coverage was reached at planning in 2/3 of planning treatment volume 30 Gy, but only 4 planning treatment volume 36 Gy; conversely, the maximum dose objective was met for most of the patients on either arytenoid cartilage, but this was not the case for 51.9% and 96.3% of cricoid and thyroid cartilages, respectively. Our dosimetric results are similar to if not better than those achieved by others.

CONCLUSION

SBRT in 3 fractions for T1 glottic lesions is dosimetrically challenging. Clinical validation is awaited.

Novel predictive tools and therapeutic strategies for patients with initially diagnosed glottic cancer in the United States

OBJECTIVE

The objective of this study is to identify valuable prognostic factors, build clinical prediction nomograms, and recommend the optimal therapeutic strategy for patients with initially diagnosed glottic cancer.

METHODS

Patients were extracted from the SEER database. Cox regression analyses, survival analyses, an internal validation, the propensity score analysis, and the competing risk analysis were performed.

RESULTS

Nine overlapped factors were considered as valuable prognostic factors. Furthermore, nomograms were established for clinical prediction models to assess the 1-, 3-, and 5-year overall survival (OS) and cancer-specific survival (CSS). C-indexes, receiver operating characteristic curves, calibration curves, and decision curve analyses proved that nomograms showed better predictive accuracy, ability, and prognostic value compared to the American Joint Committee on Cancer stage. For patients in stage I, primary site surgery alone would acquire best OS and CSS. For patients in stage II, primary site surgery and/or radiation would gain better OS and CSS. For patients in stage III, radiation plus chemotherapy or primary site surgery (alone or plus radiation) would acquire better OS and CSS. Moreover, for patients in stage IV, primary site surgery plus radiation would gain better OS and CSS.

CONCLUSIONS

Nomograms could be useful for patients' counseling and guide therapeutic decision-making. Primary site surgery alone may likely be the optimal therapy for stage I glottic cancer, and primary site surgery and/or radiation may be the recommended therapy for stage II glottic cancer. The combination treatment would be the preferred choice for advanced-stage (stage III & IV) glottic cancer, and the role of chemotherapy needs to be further explored.

Dose-Volume Comparison of IMRT and PSPT Treatment Plans for Early-Stage Glottic Cancer

Purpose

To clarify the dose distribution characteristics for early-stage glottic cancer by comparing the dose distribution between intensity-modulated radiation therapy (IMRT) and passive scattering proton therapy (PSPT) and to examine the usefulness of PSPT for early-stage glottic cancer.

Materials and Methods

Computed tomography datasets of 8 patients with T1-2 glottic cancer who had been treated by PSPT were used to create an IMRT plan in Eclipse with 7 fields and a PSPT plan in XiO-M with 2 fields. Organs at risk (OARs) included the carotid arteries, arytenoids, inferior constrictor muscles, strap muscles, thyroid cartilage, cricoid cartilage, and spinal cord. The prescription dose was 66 GyRBE in 33 fractions to the planning target volume (PTV). All plans were optimized such that 95% of the PTV received 90% of the prescription dose considering that the skin was slightly spared.

Results

The superiority of the PSPT was confirmed in all OARs. In the PSPT, the dose to the contralateral carotid artery and the spinal cord, which is slightly distant from the PTV, was dramatically reduced while maintaining the dose distribution uniformity of the PTV by comparison with IMRT.

Conclusion

PSPT for early-stage glottic cancer resulted in good target dose homogeneity and significantly spared the OARs as compared with the IMRT. PSPT is expected to be effective in reducing late effects and particularly useful for young people.

Radiotherapy in the management of glottic squamous cell carcinoma

INTRODUCTION

Our purpose is to review the role radiotherapy (RT) in the treatment of glottic squamous cell carcinoma (SCC).

METHODS

A concise review of the pertinent literature.

RESULTS

RT cure rates are Tis- T1N0, 90% to 95%; T2N0, 70% to 80%; low-volume T3-T4a, 65% to 70%. Concomitant cisplatin is given for T3-T4a SCCs. Severe complications occur in 1% to 2% for Tis-T2N0 and 10% for T3-T4a SCCs. Patients with high-volume T3-T4 SCCs undergo total laryngectomy, neck dissection, and postoperative RT. Those with positive margins and/or extranodal extension receive concomitant cisplatin. The likelihood of local-regional control at 5 years is 85% to 90%. Severe complications occur in 5% to 10%.

CONCLUSIONS

RT is a good treatment option for patients with Tis-T2N0 and low-volume T3-T4a glottic SCCs. Patients with higher volume T3-T4 cancers are best treated with surgery and postoperative RT.

Is Single Cord Irradiation Going to Be a New Standard for T1a Glottic Carcinoma?

Purpose and Objective: To evaluate the disease-free survival, overall survival, dosimetric, and voice handicap index (VHI) results of T1a glottic invasive squamous cell carcinoma (SCC) patients who underwent hypofractionated single vocal cord irradiation (HSVCI).

Materials and Methods: The data of 18 patients with stage T1a glottic SCC were collected prospectively and analyzed retrospectively between July 2016 and July 2019. Patients were immobilized using a custom-fitted thermoplastic face and shoulder mask in hyperextension position. The CT scan was performed with 1-mm-thick slices. A planned target volume (PTV) margin of 3 mm was given to clinical target volume (CTV) in all directions, and 13 organs at risk were identified. Patients were prescribed a total of 5760–5808 cGy in 15–16 fractions. Patients had daily cone-beam computed tomography (CBCT), and the treatment was carried out with the physician. VHI test was applied to patients before and at the end of radiotherapy (RT) and 1, 2, 3, 4, and 6 months after the completion of RT.

Results: Local control and overall survival rate is 100% for a median of 18 months (6–44 months) of follow-up. A patient was diagnosed with 2nd primary lung cancer and active treatment still continues. All patients completed the treatment within the scheduled time. Grade 1–2 dysphagia and dermatitis occurred in all patients, and no grade 3 and above side effects were observed. The mean values of VHI were 37.00, 39.83, 38.28, 17.17, 12.22, 8.56, and 6.06 at the beginning of RT, at the end of RT, and 1, 2, 3, 4, and 6 months after RT, respectively.

Conclusion: Compared to surgery and conventional laryngeal radiotherapy, HSVCI is an alternative treatment method for T1a glottic cancer by reducing the treatment time to 3 weeks, facilitating recurrence treatment, and providing effective sound quality without compromising local control. Considering that ~80% of recurrences in glottic cancer occur within the first 2 years, 100% local control in a median of 18 months is extremely successful, but long-term follow-up is essential to observe possible late side effects.

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).

Intensity-modulated radiation therapy in early stage squamous cell carcinoma of the larynx: treatment trends and outcomes

Purpose

Definitive radiotherapy remains a primary treatment option for early stage glottic cancer. Intensity-modulated radiation therapy (IMRT) has emerged as the standard treatment technique for advanced head and neck cancers, whereas three-dimensional conformal radiotherapy (3D-CRT) has remained standard for early glottic cancers. We used the National Cancer Database (NCDB) to identify predictors of IMRT use and effect on outcome in these patients.

Materials and Methods

We queried the NCDB from 2004–2015 for squamous cell carcinoma of the glottic larynx staged Tis-T2N0 treated with radiation alone. Logistic regression was used to identify predictors of IMRT. Cox regression was used to identify factors predictive of overall survival. Propensity matching was conducted to account for indication bias.

Results

We identified 15,627 patients, of which 11% received IMRT. IMRT use rose from 2% in 2004 to 16% in 2015. Predictors of IMRT include: increased comorbidity, T2 stage, urban location, chemotherapy, treatment at an academic center, and later treatment year. Predictors of improved survival were female gender, higher income, lower stage, no chemotherapy, academic facility, and more remote year. There was no difference in survival between 3D-CRT and IMRT across all stages.

Conclusions

The rate of IMRT use for early stage glottic laryngeal cancer has increased over time. There was no difference in outcome in patients receiving IMRT versus 3D-CRT across the cohort.

Comparison of Current Surgical and Non-Surgical Treatment Strategies for Early and Locally Advanced Stage Glottic Laryngeal Cancer and Their Outcome

For the treatment of early and locally advanced glottic laryngeal cancer, multiple strategies are available. These are pursued and supported by different levels of evidence, but also by national and institutional traditions. The purpose of this review article is to compare and discuss the current evidence supporting different loco-regional treatment approaches in early and locally advanced glottic laryngeal cancer. The focus is kept on randomized controlled trials, meta-analyses, and comparative retrospective studies including the treatment period within the last twenty years (≥ 1999) with at least one reported five-year oncologic and/or functional outcome measure. Based on the equipoise in oncologic and functional outcome after transoral laser surgery and radiotherapy, informed and shared decision-making with and not just about the patient poses a paramount importance for T1-2N0M0 glottic laryngeal cancer. For T3-4aN0-3M0 glottic laryngeal cancer, there is an equipoise regarding the partial/total laryngectomy and non-surgical modalities for T3 glottic laryngeal cancer. Patients with extensive and/or poorly functioning T4a laryngeal cancer should not be offered organ-preserving chemoradiotherapy with salvage surgery as a back-up plan, but total laryngectomy and adjuvant (chemo) radiation. The lack of high-level evidence comparing contemporary open or transoral robotic organ-preserving surgical and non-surgical modalities does not allow any concrete conclusions in terms of oncological and functional outcome. Unnecessary tri-modality treatments should be avoided. Instead of offering one-size-fits-all approaches and over-standardized rigid institutional strategies, patient-centered informed and shared decision-making should be favored.

Intensity-modulated radiotherapy for stage I glottic cancer: a short-term outcomes compared with three-dimensional conformal radiotherapy

Purpose

To investigate the differences in treatment outcomes between two radiation techniques, intensity-modulated radiotherapy (IMRT) and three-dimensional conformal radiotherapy (3DCRT).

Materials and Methods

We retrospectively analyzed 160 (IMRT = 23, 3DCRT = 137) patients with stage I glottic cancer treated from January 2005 through December 2016. The IMRT was performed with TomoTherapy (16 patients), volumetric-modulated arc therapy (6 patients), and step-and-shoot technique (1 patient), respectively. The 3DCRT was performed with bilateral parallel opposing fields. The median follow-up duration was 30 months (range, 31 to 42 months) in the IMRT group and 65 months (range, 20 to 143 months) in the 3DCRT group.

Results

The 5-year overall survival and 3-year local control rates of the 160 patients were 95.7% and 91.4%, respectively. There was no significant difference in 3-year local control rates between the IMRT and 3DCRT groups (94.4% vs. 91.0%; p = 0.587). Thirteen of 137 patients in the 3DCRT group had recurrences. In the IMRT group, one patient had a recurrence at the true vocal cord. Patients treated with IMRT had less grade 2 skin reaction than the 3DCRT group, but this had no statistical significance (4.3% vs. 21.2%; p = 0.080).

Conclusion

IMRT had comparable outcomes with 3DCRT, and a trend of less acute skin reaction in stage I glottic cancer patients

Feasibility of single vocal cord irradiation as a treatment strategy for T1a glottic cancer

BACKGROUND

Generally, radiotherapy for patients with early glottic cancer includes treatment of the whole larynx. This study was conducted to evaluate the treatment outcomes and toxicity in patients who received single vocal cord irradiation (SVCI) for T1a classification glottic cancer.

METHODS

A total of 34 patients diagnosed with clinical T1aN0M0 classification squamous cell carcinoma of the glottis who received radiotherapy to the single vocal cord were included for analysis.

RESULTS

Median follow-up period was 41.3 months (range, 6.4-124.5 months). The 3-year and 5-year local control (LC) rates were both 96.8%. Grade 3 radiation dermatitis was observed as severe acute toxicity in two (6%) patients. No patients experienced any severe late toxicity events during follow-up.

CONCLUSIONS

SVCI showed good LC, low acute and late toxicities, and reasonable voice recovery. SVCI may be considered a feasible treatment strategy for patients with T1a glottic cancer.

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.

A Review of Controversial Issues in the Management of Head and Neck Cancer: A Swiss Multidisciplinary and Multi-Institutional Patterns of Care Study-Part 2 (Radiation Oncology)

Background: The Head and Neck Cancer Working Group of Swiss Group for Clinical Cancer Research (SAKK) has investigated the level of consensus (LOC) and discrepancy in everyday practice of diagnosis and treatment in head and neck cancer.

Materials and Methods: An online survey was iteratively generated with 10 Swiss university and teaching hospitals. LOC below 50% was defined as no agreement, while higher LOC were arbitrarily categorized as low (51–74%), moderate (75–84%), and high (≥85%).

Results: Any LOC was achieved in 62% of topics (n = 60). High, moderate, and low LOC were found in 18, 20, and 23%, respectively. Regarding Head and Neck Surgery, Radiation Oncology, Medical Oncology, and biomarkers, LOC was achieved in 50, 57, 83, and 43%, respectively.

Conclusions: Consensus on clinical topics is rather low for surgeons and radiation oncologists. The questions discussed might highlight discrepancies, stimulate standardization of practice, and prioritize topics for future clinical research.

Influencing Factors on Radiotherapy Outcome in Stage I-II Glottic Larynx Cancer-A Multicenter Study

Background and Purpose: Larynx cancer represents one of the most frequently diagnosed head and neck malignancies, which is most often confined to the glottic area. The aim of this study was to report the oncological outcome and identify prognostic factors in early-stage glottic squamous cell carcinoma treated with radiotherapy. Material and Methods: Patients (n = 761) diagnosed and treated in 10 centers between 1990 and 2015 were retrospectively analyzed. Probabilities of loco-regional control (LRC) and overall survival (OS) were calculated and possible prognostic factors were analyzed using Cox proportional hazards models. Results: The median follow-up was 63 months (range: 2-243). Three hundred and sixty-four, 148 and 249 patients had cT1a, cT1b, and cT2 stage I-II disease, respectively. Five and 10-years LRC/OS rates in the whole cohort were 83/82% and 80/68%, respectively. Three patients developed distant recurrences. In univariate analysis, male sex (HR: 3.49; 95% CI: 1.47-11.37; p < 0.01), T2 vs. T1a (HR: 1.62; 95% CI: 1.08-2.43; p = 0.02) and anterior commissure involvement (ACI) (HR: 1.66; 95% CI: 1.38-2.45; p < 0.01) were associated with impaired LRC. In multivariate analysis, male sex (HR: 3.42; 95% CI: 1.44-11.17; p < 0.01) and ACI (HR: 1.51; 95% CI: 1.01-2.28; p = 0.047) remained poor prognostic factors. No relation of treatment technique and biologically equivalent dose (BED) to oncological outcome was identified except for higher BED₁₀(L = 25; T = 1) yielding better LRC in T1a tumors (p = 0.04) in univariate analyses. Conclusion: Our results highlight the negative impact of ACI on tumor control. A less-expected finding was the impact of sex on tumor control. Further research is needed to validate its prognostic value and investigate any related biologic or behavioral factors, which may be modified to improve oncologic outcome.

Defining the low-risk salvage laryngectomy-A single-center retrospective analysis of pharyngocutaneous fistula

Objectives

Salvage total laryngectomies (STL) are not a homogeneous group. Most will fall into two groups: i) Patients with previous AJCC stage I/II larynx cancer who have had radiotherapy to the larynx only (STL‐LOR), or ii) Patients who have had previous AJCC stage III/IV larynx cancer and subsequent radiotherapy to the larynx and draining nodal basins with concurrent cisplatin chemotherapy (STL‐CRT). We aimed to compare PCF rates following STL in these two groups.

Methods

A retrospective review of the department's cohort between January 2010 and August 2015 was conducted.

Results

Seventy‐seven patients underwent total laryngectomy for larynx cancer between January 2010 and August 2015. There were 10 post‐laryngectomy fistulas (13.0%). Three of these occurred in the 38 patients undergoing primary total laryngectomy (PTL), and seven in the 39 patients undergoing STL, rates of 7.9% and 17.9%, respectively. Twenty‐two patients had received radiation to the larynx alone without chemotherapy (STL‐LOR) for initial Stage I/II disease. Eleven patients had received laryngeal and neck irradiation plus cisplatin chemotherapy (STL‐CRT) for initial stage III/IV disease. Of the 22 STL‐LOR patients, two developed PCF (9.1%). Of the 11 STL‐CRT patients, five developed PCF. There was no difference in the rate of PCF between PTL and STL‐LOR. There was a statistically significant increase in PCF in STL‐CRT versus PTL (p = .009) and in PCF in STL‐CRT versus STL‐LOR (p = .027).

Conclusion

Salvage laryngectomies are often treated as a homogenous group. We demonstrate that PCF rates vary significantly depending on preoperative radiation fields and the use of chemotherapy.

Level of Evidence

2b.

Dose de-escalation to the normal larynx using conformal radiotherapy reduces toxicity while maintaining oncologic outcome for T1/T2 glottic cancer

We evaluated the efficacy of dose de-escalation to the normal larynx using conformal radiotherapy (CRT) for T1/T2 glottic cancer. For conventional RT (2DRT, n = 38), the laryngeal box received a median equivalent dose in 2 Gy fractions (EQD2) of 66 Gy. For CRT (n = 42; 3D-CRT, 20; intensity-modulated RT, 22), clinical target volume (CTV)1 (gross tumor with a 3-mm margin) and CTV2 (laryngeal box) received median EQD2s of 66.6 Gy and 52.2 Gy, respectively. With a 71-month median follow-up, five-year local control and overall survival rates for 2DRT vs. CRT were 88.1% vs. 95.1% (p = 0.405) and 94.7% vs. 90.7% (p = 0.102), respectively. Grade 2 and 3 pharyngitis rates were 52.6% and 5.3% for 2DRT vs. 35.7% and 2.4% for CRT (p = 0.121). Grade 2 and 3 dermatitis rates were 42.1% and 2.6% for 2DRT vs. 35.7% and 0% for CRT (p = 0.013). The maximum phonation time increased from 12.1 ± 7.1 to 14.0 ± 6.6 seconds after 2DRT (p = 0.375) and from 12.0 ± 5.5 to 13.8 ± 10.1 seconds after CRT (p = 0.313). Fundamental frequency decreased from 150.6 ± 40.3 to 121.9 ± 30.2 Hz after 2DRT (p = 0.039) and from 138.5 ± 31.9 to 126.1 ± 23.7 Hz after CRT (p = 0.058). CRT can effectively de-escalate the normal larynx dose while maintaining oncologic outcome and voice quality.

Evaluating Post-Radiotherapy Laryngeal Function with Laryngeal Videostroboscopy in Early Stage Glottic Cancer

Objective

Dysphonia is common among patients with early stage glottic cancer. Laryngeal videostroboscopy (LVS) has not been routinely used to assess post-radiotherapy (RT) voice changes. We hypothesized that LVS would demonstrate improvement in laryngeal function after definitive RT for early-stage glottic cancer.

Study design

Blinded retrospective review of perceptual voice and stroboscopic parameters for patients with early glottic cancer and controls.

Setting

High-volume, single-institution academic medical center.

Subjects and methods

Fifteen patients underwent RT for Tis-T2N0M0 glottic cancer and were evaluated with serial LVS exams pre- and post-RT. Stroboscopic assessment included six parameters: vocal fold (VF) vibration, VF mobility, erythema/edema, supraglottic compression, glottic closure, and secretions. Grade, roughness, breathiness, asthenia, strain (GRBAS) voice perceptual scale was graded in tandem with LVS score. Assessments were grouped by time interval from RT: pre-RT, 0–4, 4–12, and >12 months post-RT.

Results

60 LVS exams and corresponding GRBAS assessments were reviewed. There were significant improvements in ipsilateral VF motion (P = 0.03) and vibration (P = 0.001) and significant worsening in contralateral VF motion (P < 0.001) and vibration (P = 0.008) at >12 months post-RT. Glottic closure significantly worsened, most prominent >12 months post-RT (P = 0.01). Composite GRBAS scores were significantly improved across all post-RT intervals.

Conclusion

LVS proved to be a robust tool for assessing pre- and post-RT laryngeal function. We observed post-RT improvement in ipsilateral VF function, a decline in contralateral VF function, and decreased glottic closure. These results demonstrate that LVS can detect meaningful changes in VF and glottic function and support its use for post-RT evaluation of glottic cancer patients.

Larynx motion considerations in partial larynx volumetric modulated arc therapy for early glottic cancer

INTRODUCTION

To assess laryngeal motion in early glottic cancer in order to determine safe margins for partial larynx volumetric modulated arc therapy (PL-VMAT), and to quantify dosimetric advantages of PL-VMAT.

METHODS

This prospective study included T1-2N0 glottic cancers treated with whole larynx VMAT (WL-VMAT). Pre- and mid-treatment 4D-computed tomography (4D-CT) and dynamic magnetic resonance imaging (MRI) allowed for assessment of larynx swallowing and respiratory motion. For 10 patients with lateralized lesions, PL-VMAT plans were calculated using margins derived from 4D-CT analysis.

RESULTS

Twenty patients were accrued from 2014 to 2016. Mean amplitude of larynx swallowing excursion was 23 mm and 6 mm in the superior and anterior directions, respectively. Mean respiratory motion reached 4 mm and 2 mm in superior-inferior and antero-posterior directions, respectively. Pre-treatment 4D-CT analysis identified one patient with planning CT acquired during swallowing. Mid-treatment 4D-CT revealed larynx shift relative to vertebrae in 30% of cases. PL-VMAT allowed for significant reduction of mean doses to ipsilateral carotid, contralateral carotid, thyroid gland, contralateral arytenoid and larynx. Using 8 mm internal margin for PL-VMAT, swallowing resulted in clinical target volume excursion beyond 95% isodose line during ≤1.5% of total treatment time in all patients.

CONCLUSION

Although swallowing motion is rare, rapid and easily suppressed by patients, there is a risk of systematic miss-targeting if planning CT is acquired during swallowing. Larynx position shift relative to vertebrae occurs in 1/3 of patients over the course of radiotherapy. With soft-tissue image guidance and margins accounting for respiratory motion, PL-VMAT allows safe reduction of dose to organs at risk.

T1-2 glottic cancer treated with radiotherapy and/or surgery

BACKGROUND

The optimal treatment strategy for stage I-II glottic squamous cell carcinoma (SCC) is not well-defined. This study analyzed treatment results and prognostic factors.

PATIENTS AND METHODS

This is a single-institution retrospective analysis of 244 patients with T1-2 glottic SCC who underwent normofractionated radiotherapy (RT) and/or surgery between 1990 and 2013. The primary endpoint was relapse-free survival (RFS).

RESULTS

Median age was 65 years (range: 36-92 years), the majority (82%) having stage I disease. Definitive RT was used in 82% (median dose: 68 Gy, 2 Gy per fraction). Median follow-up was 59 months. The 5‑year RFS rates were 83 and 75% (p = 0.05) for stage I and 62 and 50% (p = 0.47) for stage II in the RT and surgery groups, respectively. Multivariate analyses indicate T1 vs. T2 and RT vs. surgery as independent prognostic factors for RFS, with hazard ratios of 0.38 (95% confidence interval, CI: 0.21-0.72) and 0.53 (95% CI: 0.30-0.99), respectively (p < 0.05). The 5‑year overall and cause-specific survival rates in the whole cohort were 92 and 96%, respectively, with no significant differences between treatment groups. Anterior commissure involvement was neither a prognostic nor a predictive factor. The incidence of secondary malignancies was not significantly different between patients treated with and without RT (22 vs. 9% at 10 years, respectively, p = 0.18).

CONCLUSION

Despite a possible selection bias, our series demonstrates improved RFS with RT over surgery in stage I glottic SCC.

Intensity-modulated radiotherapy for early glottic cancer: transition to a new standard of care?

For decades, the standard of care for radiation treatment of early larynx cancers has been conventional treatment using opposed lateral fields encompassing the larynx and overlying neck structures, including the adjacent carotid arteries. While intensity-modulated radiotherapy (IMRT) has replaced conventional radiotherapy for all other head/neck cancer situations, the use of IMRT to treat early glottic cancers remains controversial. The article reviews the published experience with IMRT for this clinical situation and provides a detailed review of the literature on radiation-induced carotid toxicity and how it might apply to the controversy. Finally, we discuss whether the radiation oncology community should transition to IMRT as a new standard of care for the treatment of early glottic cancers.

Dysphagia, Speech, Voice, and Trismus following Radiotherapy and/or Chemotherapy in Patients with Head and Neck Carcinoma: Review of the Literature

Introduction. Patients with head and neck cancer suffer from various impairments due to the primary illness, as well as secondary consequences of the oncological treatment. This systematic review describes the effects of radiotherapy and/or chemotherapy on the functions of the upper aerodigestive tract in patients with head and neck cancer. Methods. A systematic literature search was performed by two independent reviewers using the electronic databases PubMed and Embase. All dates up to May 2016 were included. Results. Of the 947 abstracts, sixty articles met the inclusion criteria and described one or more aspects of the sequelae of radiotherapy and/or chemotherapy. Forty studies described swallowing-related problems, 24 described voice-related problems, seven described trismus, and 25 studies described general quality of life. Only 14 articles reported that speech pathologists conducted the interventions, of which only six articles described in detail what the interventions involved. Conclusion. In general, voice quality improved following intervention, whereas quality of life, dysphagia, and oral intake deteriorated during and after treatment. However, as a consequence of the diversity in treatment protocols and patient characteristics, the conclusions of most studies cannot be easily generalised. Further research on the effects of oncological interventions on the upper aerodigestive tract is needed.