Lung stereotactic radiation therapy: Intercomparison of irradiation devices in terms of outcome and predictive factors

PURPOSE

To compare three different radiotherapy devices able to perform pulmonary stereotactic radiotherapy: CyberKnife® (CK), Helical Tomotherapy® (HT), and volumetric modulated arc therapy (VMAT). This study aims to define the patients' outcome in terms of SBRT efficacy and toxicities depending of the device choice.

MATERIALS AND METHODS

We retrospectively analyzed the clinical, radiological, and dosimetric data of patients treated with lung SBRT between 2016 and 2020 at Lausanne University Hospital, using the Chi² test for proportions, the t-test for means comparisons, the Kaplan-Meier method for survival, and the Log-rank test and Cox-regression for intergroups comparisons.

RESULTS

We identified 111 patients treated by either CK (59.9%), VMAT (38.0%), or HT (2.1%). Compared to other techniques, CK treated comparable gross tumor volume (GTV; 2.1 vs. 1.4cm³, P=0.84) with smaller planning treatment volume (PTV; 12.3 vs. 21.9cm³, P=0.013) and lower V5 (13.5 vs. 19.9cm³, P=0.002). Local control rates at 2years were not different whatever the irradiation device, respectively of 96.2% (range, 90.8-100) and 98.1% (range, 94.4-100), P=0.68. Toxicity incidence significantly increased with V5 value>17.2% (56.0 vs. 77.4%, P=0.021).

CONCLUSION

Compared to other SBRT techniques, CK treatments permitted to treat comparable GTV with reduced PTV and V5. Toxicity incidence was less frequent when reducing the V5. CK is particularly attractive in case of multiple courses of lung SBRT or lung reirradiation.

[Re-irradiation of bone marrow compression on a focus of extra medullary hematopoiesis: Presentation of a case]

We present the case of a 40-year-old patient with β-Thalassemia major who underwent decompressive palliative radiotherapy on symptomatic intracanal extra medullary hematopoiesis on three occasions between 2016 and 2020. We delivered normo-fractionated radiotherapy at a dose of 10Gy in five fractions on vertebrae T4 to T10 and L3 to S2, 20Gy in ten fractions on vertebrae C7 to T11, and 12Gy in six fractions on vertebrae C7 to T9. The treatment was well tolerated with complete recovery of the symptomatology during the first two irradiations, and almost complete recovery after the 3rd irradiation.

Fractionated Stereotactic Radiation Therapy for Pituitary Adenomas: An alternative escalating protocol of hypofractionated stereotactic radiotherapy delivering 35Gy in 5 fractions

PURPOSE

Evaluate efficacy and toxicity of hypofractionated stereotactic radiotherapy (HSRT) for patients treated for pituitary adenoma (PA) with an alternative HSRT escalating protocol delivering 35Gy in 5 fractions.

MATERIAL AND METHODS

From June 2007 to March 2017, 29 patients with pituitary adenoma were treated in Antoine Lacassagne Cancer Centre with an alternative HSRT protocol. Prescribed dose was 35Gy in 5 fractions of 7Gy. Radiographic responses were assessed by annual MRI. Hormone blood samples were evaluated each year after HSRT.

RESULTS

A total of 29 patients aged between 23 and 86 years (median 54 years) were included. Twelve patients received HSRT for recurrent cases and 12 received postoperative adjuvant HSRT, 5 patients did not have surgery. After a median follow-up period of 47 months local control rate was 96%. One patient presented an out-field tumor regrowth 73 months after HSRT. The majority of PA were endocrine-active (18 patients, 62%). After HSRT, 8 patients (44%) presented complete response on initial secretion, 4 patients (23%) presented partial response on initial secretion. Four patients (14%) presented grade 2 or more acute radiation toxicities. One grade 4 visual disorder was observed for one patient.

CONCLUSIONS

HSRT delivering 35Gy in 5 fractions represents a feasible treatment and shows promising results to reduce hormonal overproduction and to improve local control in PA.

A priori quality assurance using a benchmark case of the randomized phase 2 GORTEC 2014-14 in oligometastatic head and neck cancer patients

PURPOSE

A Benchmark Case (BC) was performed as part of the quality assurance process of the randomized phase 2 GORTEC 2014-14 OMET study, testing the possibility of multisite stereotactic radiation therapy (SBRT) alone in oligometastatic head and neck squamous cell carcinoma (HNSCC) as an alternative to systemic treatment and SBRT.

MATERIAL AND METHODS

Compliance of the investigating centers with the prescription, delineation, planning and evaluation recommendations available in the research protocol was assessed. In addition, classical dosimetric analysis was supplemented by quantitative geometric analysis using conformation indices.

RESULTS

Twenty centers participated in the BC analysis. Among them, four major deviations (MaD) were reported in two centers. Two (10%) centers in MaD had omitted the satellite tumor nodule and secondarily validated after revision. Their respective DICE indexes were 0.37 and 0 and use of extracranial SBRT devices suboptimal There were significant residual heterogeneities between participating centers, including those with a similar SBRT equipment, with impact of plan quality using standard indicators and geometric indices.

CONCLUSION

A priori QA using a BC conditioning the participation of the clinical investigation centers showed deviations from good SBRT practice and led to the exclusion of one out of the twenty participating centers. The majority of centers have demonstrated rigorous compliance with the research protocol. The use of quality indexes adds a complementary approach to improve assessment of plan quality.

Stereotactic Pelvic Reirradiation for Locoregional Cancer Relapse

AIMS

Up to 40% of patients who have received radiation for a pelvic malignancy will develop locoregional recurrence in the previously irradiated volume. Stereotactic body radiotherapy (SBRT) has been used in the oligometastatic setting, and provides an ablative approach ideal for reirradiation. The purpose of this study was to evaluate the outcomes after SBRT reirradiation of extraosseous recurrences in the pelvis.

MATERIALS AND METHODS

This single institution retrospective study evaluated patients treated with SBRT reirradiation in the pelvis from January 2011 to February 2018. Patients with more than five oligometastatic lesions, >7 cm in size, and recurrence within the prostate were excluded.

RESULTS

In total, 30 patients were treated with SBRT with a median follow-up of 29.4 months. The primary tumour sites were most commonly rectum (30.8%) and prostate (30.8%). The median time interval between irradiation for the primary and SBRT reirradiation was 48 months (3-245). The typical reirradiation treatment was 35 Gy in five fractions, the median gross tumour volume size was 10.2 (0.3-110.5) ml and the most common target was the iliac nodes (40%). There were three (10%) acute grade 3 toxicities and no late grade 3 or more toxicities. At 12/24 months, local relapse-free survival, metastasis-free survival, progression-free survival and overall survival were 67.7%/50.7%, 67%/41.7%, 34.8%/14.9% and 83.2%/62.5%, respectively. On univariate analysis, improved local control was associated with low gross tumour volume (<10 ml) (P = 0.003) and prostate primary (P = 0.02), but was no longer significant on multivariate analysis. The proximity of organ at risk to the target did not significantly correlate with worse toxicity (P = 0.14) or tumour coverage (gross tumour volume: P = 0.8, planning target volume: P = 0.4).

CONCLUSION

SBRT pelvic reirradiation in oligometastatic patients is a safe and effective treatment modality. Careful consideration should be taken with larger tumour size, as it may be associated with worse oncological and toxicity outcome.

[Re-irradiation of head and neck cancers: Target volumes, technical evolutions and prospects]

Malignant tumors of the head and neck have a predominantly regional recurrence pattern, with most deaths resulting from this progression. Optimization of re-radiation in recurrence setting is a major objective for these patients. Extensive research has been carried out with the PubMed search engine to find publications dealing with this topic. The first attempts to reirradiate the ORL sphere date back to the 1980s and the first to be performed by intensity modulation conformational radiotherapy (IMRT) date back to the late 1990s. Compared to 3 dimensional conformal radiotherapy, IMRT improves clinical outcomes and reduces toxicity. In IMRT series, associated or not with concomitant chemotherapy, the locoregional control obtained at 2 years was of the order of 45 to 65% and the overall survival of 15 to 60%, depending on predictive factors. Grade 3 acute toxicity occurred on the order of 10 to 30% and late-grade 3 toxicity on the order of 15 to 50%. In a selected population with low volumes tumors, stereotactic re-irradiation at a minimum dose of 35Gy obtained outcome comparable to IMRT. Re-irradiation of head and neck tumors by proton therapy is rare. The toxicity rate appears to be lower than that usually seen after photon therapy. However, we do not have a long follow-up. This technique therefore remains reserved for search protocols and represents a future perspective in these situations.