SBRT in 3 Fractions for T1 Glottic Cancer

PURPOSE/OBJECTIVE(S)

The purpose of this study was to report the results of a mature phase II study.

MATERIALS/METHODS

This was a prospective study at a single institution that were enrolling patients with T1 glottic cancer. The true vocal cords (TVCs) were divided into thirds and the third(s) containing disease prescribed 36 Gy in 3 fractions. The portions of the TVCs next to the involved one were planned to receive 30 Gy in 3 fxs. The remaining parts of the TVCs as well the rest of the larynx was tentatively spared. SBRT was delivered by a LINAC-based approach using multiple arcs (VMAT). 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. A generalized linear mixed model was used to analyze longitudinal functional data and the actuarial approach was used to report late toxicity prevalence rates. The planned sample size, 75 patients, was calculated to reject the hypothesis of a 2-yr local control (LC) of 85% against the alternative hypothesis of 95%. The median follow-up time is 40 months (IQR: 31.5-47.3 months).

RESULTS

Accrual was discontinued after 33 patients due to concerns on late toxicity rates on both the mucosa and the cartilages. Median age was 66 yrs (IQR: 60-71 yrs). T stage was as follows: T1a: 23 pts (69.7%); T1b: 10 pts (30.3%). Only two patients never smoked, while of the remaining ones, 13 (41.9%) kept smoking after SBRT despite appropriate counseling. At last, follow up, all patients are alive and without evidence of disease but one patient who died 21.3 months after SBRT for intercurrent causes. The observed local control rate of 100% allows to reject the null hypothesis because, according to the binomial distribution, the probability of not observing at least one recurrence out of the accrued 33 patients is <0.5% if a 2-yr LR ≤85% would be true. All but 5 patients developed transient confluent mucositis of the treated volume with a prevalence peak at 19 days after SBRT. 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 (range: 9.1-24.5 months). The actuarial prevalence of any necrosis is 3.0%, 1.3% and 0.8% at 12, 24 and 36 months after SBRT, respectively, with a peak at 6.1% between 9.9 and 11.9 months. All 4 soft tissue events healed with conservative therapy after a median time of 2.5 months (range: 1-12.2 months). One patient with chondronecrosis refused total laryngectomy and is alive with persistent toxicity 22.9 months after its onset; the other patient underwent endoscopic removal of the necrotic arytenoid and he is alive without evidence of disease or further complications more than 2 years afterwards. Patient reported outcomes (VHI) will be presented as well.

CONCLUSION

SBRT to 36/30 Gy in 3 fractions is highly effective in controlling T1 true vocal cord carcinoma, but necrosis, though mostly transient, is a concern. Based on the present results, a reduction in total doses is justified and a novel phase II study is ongoing.

DCE-MRI-Based Atlas for Prostate Bed Recurrence after Radical Prostatectomy: Consistency of CTV Delineation with the Available Contouring Guidelines

PURPOSE/OBJECTIVE(S)

To create a magnetic resonance image (MRI)-based atlas of prostate bed recurrence for prostate cancer patients undergoing salvage radiotherapy (sRT) after radical prostatectomy and to evaluate the consistency of contouring guidelines for the prostatic fossa clinical target volume (PF-CTV) delineation.

MATERIALS/METHODS

Patients with biochemical recurrence and prostate bed lesions at MRI before sRT were included. A reference patient was identified and the lesion(s) of each patient was mapped by a deformable co-registration among T2 weighted (T2w) images. The structure sets were combined to create a 3D recurrence incidence map, overlapped on T2w reference set, then transferred to the planning CT. The volume and the location of the lesions were extracted. On the reference CT, 5 PF-CTV contouring strategies were implemented: Radiation Therapy Oncology Group (RTOG); European Organization for Research and Treatment of Cancer (EORTC); Francophone Group of Urological Radiotherapy (GFRU); Faculty of Radiation Oncology Genito-urinary Group (FROGG) and Princess Margaret Hospital (PMH). Coverage was assessed after identifying the centroid of each lesion: if the centroid was included in the PF-CTV, the coverage was considered complete (fully covered-FC), otherwise uncovered (UC). The coverage was evaluated for each contouring strategy and compared with the chi-squared test; the strength of the correlation was assessed with the phi coefficient.

RESULTS

A total of 112 patients with 124 recurrences were identified. The lesions were located at the vesicourethral anastomosis (VUA), around the bladder neck (BN) and beyond the bladder (RV) in 63, 36 and 25 cases. Regardless the contouring strategy, 89.1% of the lesions were FC. Coverage was higher (p<0.001) for BN (95.6%) over RV (83.2%) and VUA (73.7%) lesions. FC/UC rates were 66.1%/33.9%, 83.9%/16.1%, 89.5%/10.5%, 83.1%/16.9%, 87.1%/12.9% for EORTC, FROGG, GFRU, RTOG and PMH, respectively. At pair-wise comparison, the EORTC definition had lower coverage (p<0.001) and was poorly correlated to the other strategies (phi values ranging 0.385-0.540, p <0.001). Conversely, the correlations between the other definitions were >0.700, the highest between PMH-FROG (0.812, p<0.001). After selecting VUA lesions only (N = 63), the probability of FC was 60.3%, 74.6%, 82.5%, 71.4% and 79.4% for EORTC, FROGG, GFRU, RTOG and PMH, respectively. The EORTC definition performed poorly than GFRU (p = 0.006) and PMH (p = 0.020). When considering lesions above the VUA (N = 61), the performance improved (FC: 72.1%, 93.4%, 96.7%, 95.1% and 95.1% for EORTC, FROGG, GFRU, RTOG and PMH, respectively) but the EORTC was significantly less covering and its correlation with the others was ≤ 0.1.

CONCLUSION

According to the criterium of coverage our data do not support the use of the EORTC definition. Here we provide an MRI-based atlas of prostatic bed recurrence that can optimize sRT contours.

Do the indices of deprivation or smoking affect post-operative 1-year mortality in patients undergoing a craniotomy for a brain tumour in a public healthcare system?

OBJECTIVE

We sought to determine the 1-year survival following craniotomy for tumour resection in a public healthcare system and analyse the effect of indices of multiple deprivation (IMD) as well as smoking, alcohol, BMI, ASA grade and medical co-morbidities on post-operative morbidity and mortality.

METHODS

This is a retrospective, single-centre study in a high volume neurosurgical centre, over a 2-year period. All patients undergoing a craniotomy for a brain tumour were included. Data was collected from the neuro-oncology database and electronic patient records. Individual patient IMD data was obtained using their postcode from a national government database. Each English postcode being ranked from 1 to 32,844, with 1 being the most deprived and 32,844 the most affluent. Descriptive results are described along with further data analysis using multiple linear and logistic regression analyses.

RESULTS

630 patients underwent an elective or urgent craniotomy for tumour. 10% of all patients underwent urgent surgery. 68% (95% CI: 64 to 71%) survived at least 1-year post-surgery. Our study found that social deprivation (IMD postcode rank) was not associated with mortality at 1 year after adjusting for potential confounding factors. Those from decile 1 had the lowest risk of death at 12 months for all tumour types (p = 0.0070). Previous smokers carried an increased risk of death at 12 months when compared with people who had never smoked RR 1.40 CI 1.10-1.78 (p = 0.006) but this risk was not evident in current smokers RR 0.92 CI 0.65-1.31 (p = 0.64). Increasing age and male gender were also found to be associated with higher mortality at 1 year (p =  < 0.001).

CONCLUSIONS

In the UK despite the discrepancy in the health of the general population between the north and south, social deprivation does not appear to be detrimental to neurooncological outcomes although smoking status, advancing age and male sex are.

NIMG-40. RAPID EARLY PROGRESSION (REP) OF GLIOBLASTOMA IS AN INDEPENDENT NEGATIVE PROGNOSTIC FACTOR: RESULTS FROM A SYSTEMATIC REVIEW AND META-ANALYSIS

INTRODUCTION

In patients with newly-diagnosed glioblastoma, rapid early progression (REP) refers to tumour regrowth between surgery and postoperative chemoradiotherapy. This systematic review and meta-analysis appraised published data on REP to better characterise and understand it.

METHODS

Systematic searches of MEDLINE, EMBASE and the Cochrane database from inception to 21/10/21. Studies describing the incidence of REP – tumour growth between the postoperative MRI scan and pre-radiotherapy MRI scan in newly-diagnosed glioblastoma, were included. The primary outcome was REP incidence.

RESULTS

From 1590 search results, 9 studies were included with 716 patients. The median age was 56.9 years (IQR 54.0-58.8 years). There was a male predominance with a median male-to-female ratio of 1.4 (IQR 1.1-1.5). The median number of days between MRI scans was 34 days (IQR 18-45 days). The mean incidence rate of REP was 45.9% (range 19.3%-72.0%) and significantly lower in studies employing functional imaging to define REP (p&lt; 0.001). REP/non-REP groups were comparable with respect to age (p=0.99), gender (p=0.33) and time between scans (p=0.81). REP was associated with shortened overall survival (HR 1.78, 95% CI 1.30-2.43, p&lt; 0.001), shortened progression-free survival (HR 1.78, 95% CI 1.30-2.43, p&lt; 0.001), subtotal resection (OR 6.96, 95% CI 4-51-10.73, p&lt; 0.001) and IDH wildtype versus mutant tumours (OR 0.20, 95% CI 0.02-0.38, p=0.03). MGMT promoter methylation was not associated with REP (OR 1.29, 95% CI 0.72-2.28, p=0.39).

CONCLUSIONS

REP occurs in almost half of patients with newly-diagnosed glioblastoma and has a strongly negative prognostic effect. Future studies should investigate its biology and effective treatment strategies.

Seizure Outcome After Surgery for Insular High-Grade Glioma

BACKGROUND

The insular cortex is an eloquent island of mesocortex surrounded by vital structures making this region relatively challenging to neurosurgeons. Historically, lesions in this region were considered too high risk to approach given the strong chance of poor surgical outcome. Advances in recent decades have meant that surgeons can more safely access this eloquent region. Seizure outcome after excision of insular low-grade gliomas is well reported, but little is known about seizure outcomes after excision of insular high-grade gliomas.

METHODS

A retrospective analysis was performed of all patients presenting with new-onset seizures during 2015-2019 who underwent excision of an insular high-grade glioma at 3 regional neurosurgical centers in the United Kingdom.

RESULTS

We identified 38 patients with a mean (SD) age of 45.7 (15.3) years with median follow-up of 21 months. At long-term follow-up, of 38 patients, 23 were seizure-free (Engel class I), 2 had improved seizures (Engel class II), 6 had poor seizure control (Engel class III/IV), and 7 died.

CONCLUSIONS

Excision of insular high-grade gliomas is safe and results in excellent postoperative seizure control.

Managing teenage/young adult (TYA) brain tumors: a UK perspective

Tumors of the CNS are among the commonest malignancies occurring in teenage/young adult patients (i.e., those aged between 15 and 24 years). The treatment of this patient population is challenging. Adolescence and young adulthood are a turbulent period of life, with physical, emotional, social and cognitive changes. Best practice advocates their treatment in dedicated teenage/young adult units, with multidisciplinary team input and access to clinical trials. Treatment of CNS malignancies is dependent upon histological subtype and staging, with varying combinations of surgery, radiotherapy and chemotherapy used. Clinical trials directly targeted at this patient population are rare; treatments are based on pediatric protocols as studies have demonstrated improved outcomes in patients (with other malignancies) treated as such. Scope for improvement lies in minimizing patient risk of recurrence and long-term sequelae of treatment. Molecular characterization of tumors may provide further information.

[The optimization of the treatment and timing of the intervention by a nephrologist in pre-dialytic chronic renal insufficiency]

BACKGROUND

Early referral to nephrologists of patients with chronic renal failure (CRF) reduces morbidity and mortality in dialysis. Aim of this work is to evaluate the condition of early and late referral, and whether the two different conditions can affect the treatments.

MATERIALS AND METHODS

This is a prospective study with a 12-month follow-up period. During this time, we verified the prevalence of patients with serum creatinine > 1.5 mg/dL (CRF patients) and the condition of early or late referral, defined as referral to nephrologists for > or < 3 times during follow up, respectively. Diagnosis of diabetes mellitus and/or arterial hypertension, and the use of antihypertensive drugs, insulin, hypoproteic diet and erythropoietin was recorded in each patient.

RESULTS

CRF (mean serum creatinine value = 2.11+/-1.52 mg/dL) was observed in 190 patients aged 72.05+/-11.62 years. The prevalence of CRF was 4718 pmp. Diabetes and hypertension were diagnosed in 107 subjects (56.3%) and 152 subjects (80%), respectively. Only 74.2% (no. 141) of the patients with CRF was habitually followed by the nephrologist and the frequency was directly correlated to the degree of CRF: 100% of the patients with Creatinine Clearance (Cr Cl) < 25 mL/min, 70% with Cr Cl >25 < 50, and 0% with Cr Cl >50 < 80 mL/min. Early referral was coupled with a wider use of a hypoproteic diet, erythropietin, and the association ACE-I + Angiotensin II receptor antagonists.

CONCLUSION

In conclusion, our data show a prevalence of CRF that is at least 5 times greater than that of dialysis patients. The condition of late referral is present in about 30% of the CRF population from the time of the initial phases of renal disease. Referral time affects the modalities of the treatment.

Stereolithographic modelling as an aid to orbital brachytherapy

PURPOSE

This paper describes the technique of stereolithographic biomodelling and its application to a patient who was treated using orbital brachytherapy.

METHODS AND MATERIALS

The process uses a moving laser beam, directed by a computer, to draw cross-sections of the model onto the surface of photo-curable liquid plastic. Using a stereolithographic apparatus (SLA), solid or surface data is sliced by software into very thin cross-sections. A helium cadmium (HeCd) laser then generates a small intense spot of ultraviolet (UV) light that is moved across the top of a vat of liquid photo monomer by a computerised optical scanning system. The laser polymerises the liquid into a solid where it touches, precisely printing each cross-section. A vertical elevator lowers the newly formed layer, and a recoating and levelling system establishes the next layer's thickness. Successive cross-sections (0.25 mm thick), each one adhering to the one below, are built one on top of the other, to form the part from the bottom up. The biomodel allowed the implant to be planned in detail prior to the surgery. The accurate placement of brachytherapy catheters was assured, and the dosimetry could be determined and optimised prior to the definitive procedure.

CONCLUSIONS

Stereolithography is a useful technique in the area of orbital brachytherapy. It allows the implant to to be carried out with greater accuracy and confidence. For the patient, it minimises the risk to the eye and provides them with a greater understanding of the procedure.