Standardisation of Target Volume Delineation for Carotid-sparing Intensity-modulated Radiotherapy in Early Glottis Cancer

Dosimetric impact of VMAT delivery angles for early glottic cancer treatment

This study investigates the dosimetric effects of different gantry rotation angles used in volumetric modulated arc therapy (VMAT) for early glottic carcinoma. VMAT treatment plans using full-arc, half-arc, and partial-arc gantry rotation angles were generated from 22 computed tomography datasets of early-stage (T1-2N0) glottic laryngeal cancer. Dosimetric parameters associated with the planning target volume (PTV) and organs at risk (OARs), specifically the carotid arteries and thyroid, were compared. To assess the robustness of the VMAT plans, dose variations were analyzed by introducing positional shifts of 1, 3, and 5 mm from the isocenter of each plan along the superior-inferior, left-right, and anterior-posterior axes. Furthermore, we examined the size of the PTV, the air cavity volume within the PTV, and the variability of the beam path length through the gantry angles to investigate their correlations with PTV dose variations in the presence of positioning errors. Compared to full-arc and half-arc plans, the dosimetric parameters of partial-arc plans were found to be higher in PTV (D2%, D5%, D50%, and Dmean) and lower in OARs, while their dose variations of OAR parameters were greater for positioning errors. In addition, a correlation was observed between PTV size and PTV dose variations. Air cavity volume and depth variability were also correlated with some PTV parameters, depending on the arc plan. The results presented in this study suggest that the partial-arc gantry angles can allow higher PTV doses while minimizing OAR doses in VMAT treatment planning for early glottic cancer. However, the small delivery angles may lead to greater dose variations in the OARs when positioning errors occur.

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.

Cost-effectiveness of hypofractionated versus conventional fractionated radiotherapy for the treatment of men with early glottic cancer: a study in the Brazilian public and private health system

BACKGROUND

This study aims to evaluate whether hypofractionated radiotherapy (HYPOFRT) is a cost-effective strategy than conventional fractionated radiotherapy (CFRT) for early-stage glottic cancer (ESGC) in the Brazilian public and private health systems.

METHODS

Adopting the perspective of the Brazilian public and private health system as the payer, a Markov model with a lifetime horizon was built to delineate the health states for a cohort of 65-year-old men after with ESGC treated with either HYPOFRT or CFRT. Probabilities of controlled disease, local failure, distant metastasis, and death and utilities scores were extracted from randomized clinical trials. Costs were based on the public and private health system reimbursement values.

RESULTS

In the base case scenario, for both the public and private health systems, HYPOFRT dominated CFRT, being more effective and less costly, with a negative ICER of R$264.32 per quality-adjusted life-year (QALY) (public health system) and a negative ICER of R$2870.69/ QALY (private health system). The ICER was most sensitive to the probability of local failure, controlled disease, and salvage treatment costs. For the probabilistic sensitivity analysis, the cost-effectiveness acceptability curve indicates that there is a probability of 99.99% of HYPOFRT being cost-effective considering a willingness-to-pay threshold of R$2,000 ($905.39) per QALY (public sector) and willingness-to-pay threshold of R$16,000 ($7243.10) per QALY (private sector). The results were robust in deterministic and probabilistic sensitivity analyses.

CONCLUSIONS

Considering a threshold of R$ 40,000 per QALY, HYPOFRT was cost-effective compared to CFRT for ESGC in the Brazilian public health system. The Net Monetary Benefit (NMB) is approximately 2,4 times (public health system) and 5,2 (private health system) higher for HYPOFRT than CFRT, which could open the opportunity of incorporating new technologies.

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.

Effect of treatment modality on the long-term survival of patients with early glottic squamous cancer: a retrospective cohort study based on the SEER database

Background

The optimal treatment strategy for patients with early glottic (T1-2N0M0) squamous cancer remains unclear.

Methods

A retrospective population-based analysis was performed using the Surveillance, Epidemiology, and End Results (SEER) database. Propensity score matching (PSM) was used to balance treatment arms, and Cox regression analysis was used to determine prognostic factors for survival. Kaplan-Meier analysis, log-rank tests, and competing risk analysis were used to compare survival outcomes between treatment modalities (surgery vs. radiotherapy).

Results

Among the 3,994 eligible patients in this study, surgery was associated with improved cancer-specific survival (CSS) and overall survival (OS) compared with radiotherapy (log-rank test, P<0.05). This survival trend favoring surgery was consistent in the T1a, well/moderately differentiated grade, male, and all age subgroups. However, after the baseline characteristics were balanced with PSM, the survival outcomes (CSS and OS) did not differ significantly between the surgery and radiotherapy groups. Interestingly, surgery was associated with a 39% reduced risk of cancer-related death compared with radiotherapy in patients aged ≥70 years (hazard ratio 0.61; 95% CI: 0.43-0.87; P=0.006). However, this survival trend favoring surgery was not observed in younger patients (age <70 years), T stage subgroups, male or female subgroups, or in any of the pathological grade subgroups.

Conclusions

In patients with early glottic squamous cell carcinoma undergoing surgery or radiotherapy, there is no sufficient evidence favoring one method over another in terms of survival. However, surgery is recommended in patients aged ≥70 years because, in this group, it was associated with improved survival outcomes compared with radiotherapy.

Prevalence of carotid plaque stenosis after head and neck radiotherapy – an observational study of 156 survivors

Summary: Background: Radiotherapy for head and neck cancer (HNC) represents a well-known predisposing factor for asymptomatic carotid artery lesions and acute cerebrovascular accidents. Our aim is to provide contemporary estimates on the prevalence, severity, and characteristics of carotid artery lesions in HNC survivors. Patients and methods: We prospectively included HNC patients who underwent radiotherapy and were free from the disease at the time of duplex ultrasound evaluation. Patients were re-contacted telephonically and those who agreed to participate were invited for an ambulatory visit when the investigators collected clinical information and performed duplex ultrasound examination based on a predefined protocol. Results: A total of 156 patients were included and underwent duplex ultrasound examination after a mean of 65.2 months from the last session of radiotherapy. A total of 36 patients (23.1%) had normal carotid arteries; mild, non-stenotic lesions were observed in 49.4% (n = 77) of patients; severe stenotic plaques were found in 27.5% (n = 43) of patients. One patient found with an asymptomatic occlusion of the left ICA. The prevalence of major cardiovascular risk factors and high radiation dose increased proportionally with plaque severity. Low echogenicity plaque was found in 59 (37.8%) patients on the right side and 57 (36.5%) on the left side; long segment plaque in 49 (31.4%) patients on the right side and in 47 (30.1%) on the left side; an atypical location of the lesions in 42 (26.9%) patients on the right side and in 48 (30.8%) on the left side. Conclusions: The prevalence of occlusion and severe stenosis after radiotherapy for HNC was very low in our study population. Low echogenicity plaque, long segment plaque, and an atypical location were common findings. Classic cardiovascular risk factors appear to have had a causative role: a routine screening of radiotherapy-treated patients might be necessary only in patients with concomitant cardiovascular risk factors or exposed to high-dose neck radiation.

Intensity-modulated radiation therapy versus three-dimensional conformal radiotherapy in head and neck squamous cell carcinoma: long-term and mature outcomes of a prospective randomized trial

Purpose

To compare long-term disease-related outcomes and late radiation morbidity between intensity-modulated radiation therapy (IMRT) and three-dimensional conformal radiotherapy (3D-CRT) in head and neck squamous cell carcinoma (HNSCC) in the setting of a prospective randomized controlled trial.

Methods

Previously untreated patients with early to moderately advanced non-metastatic squamous carcinoma of the oropharynx, larynx, or hypopharynx (T1-T3, N0-N2b, M0) planned for comprehensive irradiation of primary site and bilateral neck nodes were randomly assigned to either IMRT or 3D-CRT after written informed consent. Patients were treated with 6MV photons to a total dose of 70Gy/35 fractions over 7 weeks (3D-CRT) or 66Gy/30 fractions over 6 weeks (IMRT). A sample size of 60 patients was estimated to demonstrate 35% absolute difference in the incidence of ≥grade 2 acute xerostomia between the two arms. All time-to-event outcomes were calculated from date of randomization until the defined event using the Kaplan-Meier method.

Results

At a median follow-up of 140 months for surviving patients, 10-year Kaplan-Meier estimates of loco-regional control (LRC); progression-free survival (PFS); and overall survival (OS) with 95% confidence interval (95%CI) were 73.6% (95%CI: 61.2–86%); 45.2% (95%CI: 32–58.4%); and 50.3% (95%CI: 37.1–63.5%) respectively. There were no significant differences in 10-year disease-related outcomes between 3D-CRT and IMRT for LRC [79.2% (95%CI: 62.2–96.2%) vs 68.7% (95%CI: 51.1–86.3%), p = 0.39]; PFS [41.3% (95%CI: 22.3–60.3%) vs 48.6% (95%CI: 30.6–66.6%), p = 0.59]; or OS [44.9% (95%CI: 25.7–64.1%) vs 55.0% (95%CI: 37–73%), p = 0.49]. Significantly lesser proportion of patients in the IMRT arm experienced ≥grade 2 late xerostomia and subcutaneous fibrosis at all time-points. However, at longer follow-up, fewer patients remained evaluable for late radiation toxicity reducing statistical power and precision.

Conclusions

IMRT provides a clinically meaningful and sustained reduction in the incidence of moderate to severe xerostomia and subcutaneous fibrosis compared to 3D-CRT without compromising disease-related outcomes in long-term survivors of non-nasopharyngeal HNSCC.

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

Helical Radiotherapy in Early Laryngeal Cancers Could Lead to Excess Local Recurrence: Lessons From a Phase II Prospective Study

AIMS

A prospective study was conducted to investigate the feasibility and efficacy of carotid-sparing intensity-modulated radiotherapy (CSIMRT) in early glottic cancers (EGC).

MATERIALS AND METHODS

Eighteen patients underwent CSIMRT using helical tomotherapy to a dose of 55 Gy/20 fractions/4 weeks. Carotid intimal thickness (CIT) at prespecified carotid levels was measured using B-mode ultrasound at 6, 18 and 36 months. Serial changes in CIT were also measured in a control prospective cohort of 18 patients with head and neck cancers receiving bilateral neck nodal radiation over the same time period (54-60 Gy/30 fraction/6 weeks). The outcomes of 18 patients undergoing CSIMRT were compared against a retrospective consecutive cohort of 41 patients with EGC to confirm comparable local control.

RESULTS

No significant CIT differences were identified between patients undergoing CSIMRT versus the control group. However, four patients in the CSIMRT group had a local recurrence between 8 and 39 months. In all patients the epicentre of the recurrence was noted at the anterior part of the larynx. The 5-year local recurrence-free survival was 75.1% (95% confidence interval 56.6-99.7%). By contrast, in the group of EGC patients treated without carotid sparing, local recurrence was noted only in a single patient (patient treated with helical tomotherapy) and the 5-year local recurrence-free survival was 97.1% (95% confidence interval 91.8-100%) (Log-rank P = 0.01).

CONCLUSION

We failed to show the safety of CSIMRT using helical tomotherapy in this population of EGC patients. Use of CSIMRT also did not translate into a substantial reduction in CIT until 36 months. Use of CSIMRT using rotational arc techniques such as helical tomotherapy may be associated with a greater risk of local recurrence due to intrafractional motion interplay effects.

Outcome of Early-Stage Glottic Laryngeal Carcinoma Patients Treated with Radical Radiotherapy Using Different Techniques

Purpose

The aim was to evaluate the treatment outcomes and prognostic characteristics of patients with early-stage glottic laryngeal carcinoma who underwent radical radiotherapy (RT) with different techniques.

Patients and Methods

Radiotherapy was applied using the 2D conventional technique between 1991 and 2004 (130 patients), 3DCRT until 2014 (125 patients), and by VMAT until January 2017 (44 patients). Clinical T stages were 38 (12.7%) for Tis, 209 (69.9%) for T1, and 52 (17.4%) for T2. Radiotherapy technique and energy, anterior commissure involvement, and stage were analyzed as prognostic factors.

Results

The median total dose was 66 (50–70) Gy, and median follow-up time was 72 (3–288) months; 5-year disease-specific survival (DSS) rates were 95.8%, 95.5%, and 88.6%, respectively, in Tis, T1, and T2 stages. In multivariate analyses, anterior commissure involvement was found significant for all survival and local control rates. The patients treated with VMAT technique had better local control and DSS rates. However, these results were not statistically significant.

Conclusion

In early-stage laryngeal carcinomas, radical RT is a function sparing and effective treatment modality, regardless of treatment techniques.

Hypofractionated radiotherapy for early glottic cancer: a retrospective interim analysis of a single institution

PURPOSE

To evaluate the results of hypofractionated radiotherapy (HFX) for early glottic cancer.

MATERIALS AND METHODS

Eighty-five patients with cT1-2N0M0 squamous cell carcinoma of the glottis who had undergone HFX, performed using intensity-modulated radiotherapy (IMRT, n = 66) and three-dimensional conformal radiotherapy (3D CRT, n = 19) were analyzed. For all patients, radiotherapy was administered at 60.75 Gy in 27 fractions. Forty-three patients received a simultaneous integrated boost (SIB) of 2.3-2.5 Gy per tumor fraction.

RESULTS

The median follow-up duration was 29.9 months (range, 5.5 to 76.5 months). All patients achieved complete remission at a median of 50 days after the end of radiotherapy (range, 14 to 206 days). The 5-year rates for locoregional recurrence-free survival was 88.1%, and the 5-year overall survival rate was 86.2%. T2 stage was a prognostic factor for locoregional recurrencefree survival after radiotherapy (p = 0.002). SIB for the tumor did not affect disease control and survival (p = 0.191 and p = 0.387, respectively). No patients experienced acute or chronic toxicities of ≥grade 3. IMRT significantly decreased the dose administered to the carotid artery as opposed to 3D CRT (V35, p < 0.001; V50, p < 0.001).

Conclusions

Patients treated with HFX achieved acceptable locoregional disease control rates and overall survival rates compared with previous HFX studies. A fraction size of 2.25 Gy provided good disease control regardless of SIB administration.

Volumetric modulated arc therapy with robust optimization for larynx cancer

PURPOSE

The aim of this study was to perform a comparison between robust optimization and planning target volume (PTV)-based optimization plans using volumetric modulated arc-therapy (VMAT) by evaluating perturbed doses induced by localization offsets for setup uncertainties in larynx cancer radiation therapy.

METHODS

Ten patients with early-stage (T1-2N0) glottis carcinoma were selected. The clinical target volume (CTV), carotid arteries, and spinal cord were contoured by a radiation oncologist. PTV-based and robust optimization plans were normalized at D_50% to the PTV and D_98% to the CTV, respectively. Both optimization plans were evaluated using perturbed doses by specifying user defined shifted values from the isocenter. CTV dose (D_98%, D_50%, and D_2%), homogeneity index (HI) and conformity index (CI_95%, CI_80%, and CI_50%), as well as doses to the carotid arteries and spinal cord were compared between PTV-based and robust optimization plans.

RESULTS

The robust optimization plans exhibited superior CTV coverage and a reduced dose to the carotid arteries compared to the PTV-based optimization plans (p < 0.05). HI, CI_95% and the dose to the spinal cord did not significantly differ between the PTV-based and robust optimization plans (p > 0.05). The robust optimization plans showed better CI_80% and CI_50% compared to the PTV-based optimization plans (p < 0.05). Plan perturbed evaluations showed that the robust optimization plan has small variations in the doses to the CTV, carotid arteries, and spinal cord compared to the PTV-based optimization plan.

CONCLUSIONS

The robust optimization plan may be a suitable treatment method in radiotherapy for larynx cancer patient.