Upfront DPYD Genotyping and Toxicity Associated with Fluoropyrimidine-Based Concurrent Chemoradiotherapy for Oropharyngeal Carcinomas: A Work in Progress

Background: 5-FU-based chemoradiotherapy (CRT) could be associated with severe treatment-related toxicities in patients harboring at-risk DPYD polymorphisms. Methods: The studied population included consecutive patients with locoregionally advanced oropharyngeal carcinoma treated with carboplatin and 5-FU-based CRT one year before and after the implementation of upfront DPYD*2A genotyping. We aimed to determine the effect of DPYD genotyping on grade ≥3 toxicities. Results: 181 patients were analyzed (87 patients before and 94 patients following DPYD*2A screening). Of the patients, 91% (n = 86) were prospectively genotyped for the DPYD*2A allele. Of those screened, 2% (n = 2/87) demonstrated a heterozygous DPYD*2A mutation. Extended genotyping of DPYD*2A-negative patients later allowed for the retrospective identification of six additional patients with alternative DPYD variants (two c.2846A>T and four c.1236G>A mutations). Grade ≥3 toxicities occurred in 71% of the patients before DPYD*2A screening versus 62% following upfront genotyping (p = 0.18). When retrospectively analyzing additional non-DPYD*2A variants, the relative risks for mucositis (RR 2.36 [1.39–2.13], p = 0.0063), dysphagia (RR 2.89 [1.20–5.11], p = 0.019), and aspiration pneumonia (RR 13 [2.42–61.5)], p = 0.00065) were all significantly increased. Conclusion: The DPYD*2A, c.2846A>T, and c.1236G>A polymorphisms are associated with an increased risk of grade ≥3 toxicity to 5-FU. Upfront DPYD genotyping can identify patients in whom 5-FU-related toxicity should be avoided.

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.

Dual Inhibition of Autophagy and PI3K/AKT/MTOR Pathway as a Therapeutic Strategy in Head and Neck Squamous Cell Carcinoma

Genomic analyses of head and neck squamous cell carcinoma (HNSCC) have highlighted alterations in the phosphatidylinositol 3-kinase (PI3K) signaling pathway, presenting a therapeutic target for multiple ongoing clinical trials with PI3K or PI3K/MTOR inhibitors. However, these inhibitors can potentially increase autophagy in HNSCC and indirectly support cancer cell survival. Here, we sought to understand the relationship between the PI3K signaling pathway and autophagy during their dual inhibition in a panel of HNSCC cell lines. We used acridine orange staining, immunoblotting, and tandem sensor Red Fluorescent Protein- Green Fluorescent Protein-, microtubule-associated protein 1 light chain 3 beta (RFP-GFP-LC3B) expression analysis to show that PI3K inhibitors increase autophagosomes in HNSCC cells, but that chloroquine treatment effectively inhibits the autophagy that is induced by PI3K inhibitors. Using the Bliss independence model, we determined that the combination of chloroquine with PI3K inhibitors works in synergy to decrease cancer cell proliferation, independent of the PIK3CA status of the cell line. Our results indicate that a strategy focusing on autophagy inhibition enhances the efficacy of therapeutics already in clinical trials. Our results suggest a broader application for this combination therapy that can be promptly translated to in vivo studies.

Upfront DPYD genotyping and toxicity associated with fluoropyrimidine-based concurrent chemoradiotherapy for oropharyngeal carcinomas

6580

Background: The combination of carboplatin and 5-fluorouracil (5-FU) is effective when used concurrently with radiotherapy for locoregionally advanced oropharyngeal carcinomas (Calais et al. 1999). DPYD polymorphisms can be associated with an increased risk of severe toxicity to fluoropyrimidines (Deenen et al. 2016). Upfront screening for the DPYD*2A allele is available in the province of Québec, Canada since March 2017. This study aimed to determine the effect of upfront genotyping on grade ≥3 toxicities. Methods: The studied population included all consecutive cases of oropharyngeal carcinomas treated with 5-FU based chemoradiotherapy one year before and after the implementation of upfront DPYD*2A genotyping. All patients were treated at the Centre Hospitalier de l’Université de Montréal (CHUM) between March 2016 and April 2018. Clinical data were extracted from chart review. Extended screening for 3 supplemental at-risk DPYD variants was also retrospectively performed in August 2019. Results: 181 patients were included in the analysis (87 patients before and 94 patients after DPYD*2A screening implementation). 91% of patients (n = 86) were prospectively genotyped for the DPYD*2A allele. Of those screened, 2% (n = 2/87) demonstrated a heterozygous DPYD*2A mutation. Those two patients received cisplatin-based treatment and thus avoided 5-FU toxicities. Extended genotyping of DPYD*2A-negative patients later allowed for the retrospective identification of 6 additional patients with alternative DPYD variants (two c.2846A > T and four c.1236G > A allele mutations). Conclusions: The DPYD*2A, c.2846A > T and c.1236G > A polymorphisms are associated with an increased risk of G3-4 toxicity to 5-FU, as well as higher hospitalization rates. Upfront DPYD genotyping can identify patients in whom fluoropyrimidine-related toxicity should be avoided. This represents an interesting addition in terms of pharmacovigilance. [Table: see text]

Initial analyses of a phase I/II trial of durvalumab (D) plus tremelimumab (T) and stereotactic body radiotherapy (SBRT) for oligometastatic head and neck carcinoma

6531

Background: PD-1/PD-L1 +/- CTLA-4 blockade in head-and-neck carcinoma (HNSCC) has shown signs of clinical activity. SBRT aims to reduce tumor burden and perhaps be immune-stimulatory. This analysis seeks to assess the safety and efficacy signal of the triple treatment combination (TTC) consisting of SBRT sandwiched between cycles of D (αPD-L1) and T (αCTLA-4) in oligometastatic (2-10) HNSCC. Methods: This is a single arm multi-institutional phase I/II trial (NCT03283605). D (1500 mg) and T (75 mg) were given for 4 monthly cycles, followed by monthly D. SBRT to 2-5 lesions was administered during cycle 2. The median prescribed and maximum SBRT doses were 40 Gy (range:18-50) and 49 Gy (range:28-61), respectively, given in 3-5 fractions. Global health status was derived from EORTC QLQ C30 questionnaires. Results: At data cut-off (Dec 31, 2019), 20 patients were recruited, of which 16 had a study treatment and were analyzed. Table describes the patient characteristics. There were 1 CTCAE V5.0 Grade 2 and 1 Grade 3 (both GI) serious adverse event (SAE) attributable to D and T. Two patients had unrelated SAEs (1 Grade 3-hypercalcemia and 1 Grade 5-GI). The Grade 5 SAE was a gastric hemorrhage that occurred the night of the first D + T infusion. There was no Grade 3+ AE secondary to SBRT. Thus, SBRT did not add to the 2/16 patients who had D + T related SAEs. Global health status scores did not differ statistically between baseline (75) and cycle 3 (73). Of the 14 patients that received SBRT, 7 patients had RECIST target lesions untreated by SBRT. The best responses for these 7 patients were: 1 CR, 3 PR, and 3 SD. When SBRT treated lesions are included and analyzed per RECIST (n = 14), there were 9 PR, 3 SD and 2 PD. The estimated median progression free survival was 7.2 months. Conclusions: The first 16 evaluable patients demonstrated tolerable profiles to the TTC (D + T + SBRT) for the treatment of oligometastatic (≤10 lesions) HNSCC. Best response rates were encouraging and could be due to the addition of SBRT during immunotherapy that served to either stimulate the immune system or annihilate slow responding or immunotherapy resistant lesions. Smaller overall tumor burden and 7/16 patients being treated in first line could also have contributed to better results. Clinical trial information: NCT03283605 . [Table: see text]

Phase I/II trial of Durvalumab plus Tremelimumab and stereotactic body radiotherapy for metastatic head and neck carcinoma

BACKGROUND

The efficacy of immunotherapy targeting the PD-1/PD-L1 pathway has previously been demonstrated in metastatic head and neck squamous cell carcinoma (HNSCC). Stereotactic Body Radiotherapy (SBRT) aims at ablating metastatic lesions and may play a synergistic role with immunotherapy. The purpose of this study is to assess the safety and efficacy of triple treatment combination (TTC) consisting of the administration of durvalumab and tremelimumab in combination with SBRT in metastatic HNSCC.

METHOD

This is a phase I/II single arm study that will include 35 patients with 2-10 extracranial metastatic lesions. Patients will receive durvalumab (1500 mg IV every 4 weeks (Q4W)) and tremelimumab (75 mg IV Q4W for a total of 4 doses) until progression, unacceptable toxicity or patient withdrawal. SBRT to 2-5 metastases will be administered between cycles 2 and 3 of immunotherapy. The safety of the treatment combination will be evaluated through assessment of TTC-related toxicities, defined as grade 3-5 toxicities based on Common Terminology Criteria for Adverse Events (v 4.03), occurring within 6 weeks from SBRT start, and that are definitely, probably or possibly related to the combination of all treatments. We hypothesize that dual targeting of PD-L1 and CTLA-4 pathways combined with SBRT will lead to < 35% grade 3-5 acute toxicities related to TTC. Progression free survival (PFS) will be the primary endpoint of the phase II portion of this study and will be assessed with radiological exams every 8 weeks using the RECIST version 1.1 criteria.

DISCUSSION

The combination of synergistic dual checkpoints inhibition along with ablative radiation may significantly potentiate the local and systemic disease control. This study constitutes the first clinical trial combining effects of SBRT with dual checkpoint blockade with durvalumab and tremelimumab in the treatment of metastatic HNSCC. If positive, this study would lead to a phase III trial testing this treatment combination against standard of care in metastatic HNSCC.

TRIAL REGISTRATION

NCT03283605 . Registration date: September 14, 2017; version 1.

Accelerated radiotherapy with simultaneous integrated boost fractionation and intensity-modulated radiotherapy for advanced head and neck cancer

Objective

To determine the feasibility and toxicity profile of accelerated radiotherapy with a simultaneous integrated boost fractionation scheme with intensity-modulated radiotherapy (SIB-IMRT) with or without chemotherapy.

Study Design And Setting

Forty-nine patients with advanced head and neck cancer underwent SIB-IMRT. Concomitant chemotherapy was administered in 29 patients.

Results

Grade 3 acute toxicities included 55% mucositis, 20% odynophagia, 12% nausea, 18% hematologic, and 8% skin. There were no grade 4 toxicities or treatment-related deaths. With a median follow-up of 25 months, locoregional control was 83%, and overall survival was 80%. Of patients with grade 3 late toxicities, two patients (4% of the total) required a permanent percutaneous endoscopic gastrostomy tube, and osteonecrosis occurred in one patient (2% of the total).

Conclusions

SIB-IMRT is a feasible technique that shortens the overall treatment time in the radical treatment of patients with advanced head and neck cancer while maintaining acceptable rates of acute toxicity in this study. Although the results are promising, this approach should be considered only in the setting of a clinical trial.

Impact of geometric uncertainties on dose distribution during intensity modulated radiotherapy of head-and-neck cancer: the need for a planning target volume and a planning organ-at-risk volume

We assessed the effect of geometric uncertainties on target coverage and on dose to the organs at risk (OARS) during intensity-modulated radiotherapy (IMRT) for head-and-neck cancer, and we estimated the required margins for the planning target volume (PTV) and the planning organ-at-risk volume (PRV). For eight head-and-neck cancer patients, we generated IMRT plans with localization uncertainty margins of 0 mm, 2.5 mm, and 5.0 mm. The beam intensities were then applied on repeat computed tomography (CT) scans obtained weekly during treatment, and dose distributions were recalculated.The dose-volume histogram analysis for the repeat ct scans showed that target coverage was adequate (V(100) >/= 95%) for only 12.5% of the gross tumour volumes, 54.3% of the upper-neck clinical target volumes (CTVS), and 27.4% of the lower-neck CTVS when no margins were added for PTV. The use of 2.5-mm and 5.0-mm margins significantly improved target coverage, but the mean dose to the contralateral parotid increased from 25.9 Gy to 29.2 Gy. Maximum dose to the spinal cord was above limit in 57.7%, 34.6%, and 15.4% of cases when 0-mm, 2.5-mm, and 5.0-mm margins (respectively) were used for prv.Significant deviations from the prescribed dose can occur during IMRT treatment delivery for head-and-neck cancer. The use of 2.5-mm to 5.0-mm margins for PTV and PRV greatly reduces the risk of underdosing targets and of overdosing the spinal cord.

IMRT head and neck treatment planning with a commercially available Monte Carlo based planning system

The PEREGRINE Monte Carlo dose-calculation system (North American Scientific, Cranberry Township, PA) is the first commercially available Monte Carlo dose-calculation code intended specifically for intensity modulated radiotherapy (IMRT) treatment planning and quality assurance. In order to assess the impact of Monte Carlo based dose calculations for IMRT clinical cases, dose distributions for 11 head and neck patients were evaluated using both PEREGRINE and the CORVUS (North American Scientific, Cranberry Township, PA) finite size pencil beam (FSPB) algorithm with equivalent path-length (EPL) inhomogeneity correction. For the target volumes, PEREGRINE calculations predict, on average, a less than 2% difference in the calculated mean and maximum doses to the gross tumour volume (GTV) and clinical target volume (CTV). An average 16% +/- 4% and 12% +/- 2% reduction in the volume covered by the prescription isodose line was observed for the GTV and CTV, respectively. Overall, no significant differences were noted in the doses to the mandible and spinal cord. For the parotid glands, PEREGRINE predicted a 6% +/- 1% increase in the volume of tissue receiving a dose greater than 25 Gy and an increase of 4% +/- 1% in the mean dose. Similar results were noted for the brainstem where PEREGRINE predicted a 6% +/- 2% increase in the mean dose. The observed differences between the PEREGRINE and CORVUS calculated dose distributions are attributed to secondary electron fluence perturbations, which are not modelled by the EPL correction, issues of organ outlining, particularly in the vicinity of air cavities, and differences in dose reporting (dose to water versus dose to tissue type).