Impact of Oral Cavity Dosimetry on Patient Reported Xerostomia and Dysgeusia in the Setting of Deintensified Chemoradiotherapy.

Purpose: To determine the relationship between mean oral cavity (OC) dose (treated as a singular organ at risk) to patient reported xerostomia and dysgeusia. In addition, we will examine the relationship between oral cavity substructure doses to patient reported xerostomia and dysgeusia. All patients were treated in the setting of deintensification (60 Gy). Methods and Materials: In the study, 184 and 177 prospectively enrolled patients for de-escalated chemoradiotherapy (CRT) for human papillomavirus (HPV)-positive oropharyngeal cancer submitted PROs at 6 and 12 months, respectively using Patient-Reported Outcomes version of the Common Terminology Criteria for Adverse Events questionnaire. Patient's OC consisting of the following substructures were segmented: oral tongue, base of tongue, floor of mouth, hard and soft palate, cheek mucosa, and upper and lower lip mucosa. Ordinal logistic regression (no/mild vs moderate vs severe/very severe symptoms) was used to compare organs at risk dosimetry to patient reported xerostomia and dysgeusia at 6 and 12 months. Multivariate ordinal logistic regression models were generated. Results: Mean dose to the contralateral parotid (P = .04), OC (P = .04), and baseline patient reported xerostomia (P = .009) were significantly associated with xerostomia severity at 6 months. Only baseline xerostomia (P = .02) and mean dose to the contralateral submandibular gland (P = .0001) were significantly associated with xerostomia severity at 12 months. The only significant factor related to dysgeusia at either time point was mean dose to the OC at 12 months (P = .009). On examining substructures, the mean dose to the floor of mouth was implicated for the dose relationship to 6-month xerostomia (P = .04), and the oral tongue was found to be implicated for the relationship for 12-month dysgeusia (P = .04). Conclusions: The mean dose to the OC was found to relate to xerostomia symptoms at 6 months post-CRT and dysgeusia symptoms at 12 months post-CRT. The mean dose to the floor of mouth and oral tongue appeared to drive this relationship for xerostomia and dysgeusia symptoms, respectively. This work suggests the floor of mouth and oral tongue should be prioritized during planning over the rest of the OC. The effect of OC dose relative to other salivary structures for xerostomia appeared to depend on time post-CRT.

Prospective assessment of sparing the parotid ducts via MRI sialography for reducing patient reported xerostomia.

PURPOSE: To assess the impact of prospectively sparing the parotid ducts via MRI sialography on patient reported xerostomia for those receiving definitive radiotherapy (RT) for oropharyngeal squamous cell carcinoma. METHODS AND MATERIALS: Thirty-eight patients with oropharynx cancer to be treated with definitive RT underwent pre-treatment MRI sialograms to localize their parotid ducts. The parotid ducts were maximally spared during treatment planning. Patients reported symptoms (PRO-CTCAE and QLQ-H&N35) were collected at 6 and 12 months post-RT and compared to a historical cohort who underwent conventional parotid gland mean dose sparing. Regression models were generated using parotid and submandibular gland doses with and without incorporating the dose to the parotid ducts to determine the impact of parotid duct dose on patient reported xerostomia. RESULTS: At 6 months post-RT, 12/26 (46%) patients reported ≥moderate xerostomia when undergoing parotid ductal sparing compared to 43/61 (70%) in the historical cohort (p = 0.03). At 12 months post-RT, 8/22 (36%) patients reported ≥moderate xerostomia when undergoing parotid ductal sparing compared to 34/68(50%) in the historical cohort (p = 0.08). Using nested logistic regression models, the mean parotid duct dose was found to significantly relate to patient reported xerostomia severity at 6 months post-RT (p = 0.04) and trended towards statistical significance at 12 months post-RT (p = 0.09). At both 6 and 12 months post-RT, the addition of mean parotid duct dose significantly improved model fit (p < 0.05). CONCLUSIONS: MRI sialography guided parotid duct sparing appears to reduce the rates of patient-reported xerostomia. Further, logistic regression analysis found parotid duct dose to be significantly associated with patient reported xerostomia. A significant improvement in model fit was observed when adding mean parotid duct dose compared to models that only contain mean parotid gland dose and mean contralateral submandibular gland dose.

Prospective Assessment of Patient-Reported Dry Eye Syndrome After Whole Brain Radiation.

PURPOSE: Dry eye is not typically considered a toxicity of whole brain radiation therapy (WBRT). We analyzed dry eye syndrome as part of a prospective study of patient-reported outcomes after WBRT. METHODS AND MATERIALS: Patients receiving WBRT to 25 to 40 Gy were enrolled on a study with dry mouth as the primary endpoint and dry eye syndrome as a secondary endpoint. Patients received 3-dimensional WBRT using opposed lateral fields. Per standard practice, lacrimal glands were not prospectively delineated. Patients completed the Subjective Evaluation of Symptom of Dryness (SESoD, scored 0-4, with higher scores representing worse dry eye symptoms) at baseline, immediately after WBRT (EndRT), and at 1 month (1M), 3 months, and 6 months. Patients with baseline SESoD ≥3 (moderate dry eye) were excluded. The endpoints analyzed were ≥1-point and ≥2-point increase in SESoD score at 1M. Lacrimal glands were retrospectively delineated with fused magnetic resonance imaging scans. RESULTS: One hundred patients were enrolled, 70 were eligible for analysis, and 54 were evaluable at 1M. Median bilateral lacrimal V20Gy was 79%. At 1M, 17 patients (32%) had a ≥1-point increase in SESoD score, and 13 (24%) a ≥2-point increase. Lacrimal doses appeared to be associated with an increase in SESoD score of both ≥1 point (V10Gy: P = .042, odds ratio [OR] 1.09/%; V20Gy: P = .071, OR 1.03/%) and ≥2 points (V10Gy: P = .038, OR 1.15/%; V20Gy: P = .063, OR 1.04/%). The proportion with increase in dry eye symptoms at 1M for lacrimal V20Gy ≥79% versus <79% was 46% versus 15%, respectively, for ≥1 point SESoD increase (P = .02) and 36% versus 12%, respectively, for ≥2 point SESoD increase (P = .056). CONCLUSIONS: Dry eye appears to be a relatively common, dose/volume-dependent acute toxicity of WBRT. Minimization of lacrimal gland dose may reduce this toxicity, and patients should be counseled regarding the existence of this potential side effect and treatments for dry eye.

Phase II Trial of De-Intensified Chemoradiotherapy for Human Papillomavirus-Associated Oropharyngeal Squamous Cell Carcinoma.

PURPOSE: To report the results of a phase II clinical trial of de-intensified chemoradiotherapy for patients with human papillomavirus-associated oropharyngeal squamous cell carcinoma. MATERIALS AND METHODS: Major inclusion criteria were (1) having American Joint Committee on Cancer (AJCC) 7th edition T0-T3, N0-N2c, M0 (AJCC 8th edition T0-T3, N0-N2, M0), (2) being p16 positive, and (3) reporting minimal or remote smoking history. Treatment was limited to 60 Gy intensity-modulated radiotherapy with concurrent intravenous cisplatin 30 mg/m2 once per week. Patients with T0-T2 N0-1 (AJCC 7th edition) did not receive chemotherapy. All patients had a 10- to 12-week post-treatment positron emission tomography/computed tomography to assess for neck dissection. The primary end point was 2-year progression-free survival. Secondary end points included 2-year local-regional control, distant metastasis-free survival and overall survival, and patient-reported outcomes (European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire and the patient-reported outcomes version of the Common Terminology Criteria for Adverse Events). RESULTS: One hundred fourteen patients were enrolled (median follow-up of 31.8 months), with 81% having a minimum follow-up of 2 years. Eighty percent of patients had 10 or fewer tobacco pack-years. Two-year local-regional control, distant metastasis-free survival, progression-free survival, and overall survival were as follows: 95%, 91%, 86%, and 95%, respectively. Mean pre- and 2-year post-treatment European Organisation for Research and Treatment of Cancer quality of life scores were as follows: global, 79/84 (lower worse); swallowing, 8/9 (higher worse); and dry mouth, 14/45 (higher worse). Mean pre- and 2-year post-treatment patient-reported outcomes version of the Common Terminology Criteria for Adverse Events scores (0 to 4 scale, higher worse) were as follows: swallowing, 0.5/0.7, and dry mouth, 0.4/1.3. Thirty-four percent of patients required a feeding tube (median, 10.5 weeks; none permanent). There were no grade 3 or higher late adverse events. CONCLUSION: Clinical outcomes with a de-intensified chemoradiotherapy regimen of 60 Gy intensity-modulated radiotherapy with concurrent low-dose cisplatin are favorable in patients with human papillomavirus-associated oropharyngeal squamous cell carcinoma. Neither neoadjuvant chemotherapy nor routine surgery is needed to obtain favorable results with de-escalation.

Quality of Life for Patients With Favorable-Risk HPV-Associated Oropharyngeal Cancer After De-intensified Chemoradiotherapy.

PURPOSE: Oropharynx cancers associated with human papillomavirus (HPV) have a favorable prognosis, but current treatment approaches carry significant long-term morbidity. Strategies to de-intensify treatment in this population are under investigation, but the impact of these approaches on quality of life (QOL) is not well understood. We present patient-reported outcomes from 2 prospective studies examining de-intensified chemoradiotherapy. METHODS AND MATERIALS: This study included patients enrolled in 2 prospective phase 2 trials of de-intensified chemoradiotherapy in patients with HPV-associated oropharynx cancer who had at least 1 year of follow-up. Treatment included concurrent radiation therapy (60 Gy) and chemotherapy (weekly cisplatin, 30 mg/m2). Patients reported QOL and symptoms using the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire-C30, the European Organisation for Research and Treatment of Cancer Head and Neck Cancer Module-35, and the Eating Assessment Tool-10 instruments before treatment and at regular intervals thereafter. Changes in QOL and individual symptoms were examined over time, and multivariate analysis was used to identify clinical factors associated with recovery to baseline symptom levels. RESULTS: Of the 154 patients enrolled, 126 patients had at least 1 year of follow-up and were included in this study (median follow-up, 25 months). Global QOL, functional indices, and most individual symptoms returned to baseline 3 to 6 months after treatment. Swallowing (Eating Assessment Tool-10 score) returned to baseline function by 2 years, but dry mouth, sticky saliva, and taste/senses did not return to baseline levels. However, from 1 to 2 years, continued improvement occurred in dry mouth score (55 vs 48), sticky saliva score (35 vs 27), and senses score (24 vs 20). On multivariate analysis, unilateral radiation therapy was associated with returning to baseline level of swallowing and sticky saliva. CONCLUSIONS: The use of de-intensified chemoradiotherapy in HPV-associated oropharynx cancer led to favorable patient-reported outcomes, with early recovery of QOL and continued improvement of xerostomia and dysphagia beyond 1-year posttreatment.

Polyelectrolyte nano-scaffolds for the design of layered cellular architectures.

The design of in vitro multilayered cellular architectures that resemble the stratified, lattice-like structure in tissues poses a significant challenge for tissue engineering. There is currently no generally applicable methodology to design multilayered cellular constructs that mimic the structure of tissues in vivo. We report a novel and generalizable approach to create multilayered cellular constructs that addresses these issues. These in vitro constructs comprise alternating layers of cells and nano-scale biocompatible polyelectrolyte (PE) scaffolds. We apply this methodology to address two specific problems in hepatic tissue engineering: the design of in vitro liver sinusoidal structures and the critical need to increase viable cell mass in extracorporeal liver-assist devices. We assembled ultrathin polymer scaffolds on the top of a confluent monolayer of cells by the sequential deposition of oppositely charged PEs. The thickness of the PE scaffold lies in the nanometer range. The PE scaffold plays a dual role. First, it is a technique to culture hepatocytes in vitro that maintains their morphology, cytoskeletal structure, and liver-specific functions. Second, the nano-scaffold provides a cell-adhesive surface on which a second layer of cells can be cultured, resulting in layered architectures. We have used this approach to design layered three-dimensional hepatocyte-PE-hepatocyte constructs, hepatocyte-PE-endothelial cell constructs, and hepatocyte-PE-fibroblast constructs. As a result of its versatility, this approach can, in principle, be used to design layered cellular constructs of any tissue type, and therefore has potentially wide applications in tissue engineering, bioreactor devices, and in drug delivery. This methodology has the potential to generate realistic in vitro constructs of any tissue type.

The effect of functionalized self-assembling peptide scaffolds on human aortic endothelial cell function.

A class of designed self-assembling peptide nanofiber scaffolds with more than 99% water content has been shown to be a good biological material for cell culture. Here, we report the functionalization of one of these peptide scaffolds, RAD16-I (AcN-RADARADARADARADA-CONH2), by direct solid phase synthesis extension at the amino terminal with three short-sequence motifs. These motifs are present in two major protein components of the basement membrane, laminin 1 (YIGSR, RYVVLPR) and collagen IV (TAGSCLRKFSTM). These motifs have been previously shown to promote specific biological activities including endothelial cell adhesion, spreading, and tubular formation. Therefore, the generic functionalized peptide developed was AcN-X-GG-RADARADARADARADA-CONH2 with each motif represented by "X". We show in this work that these tailor-made peptide scaffolds enhance the formation of confluent cell monolayers of human aortic endothelial cells (HAEC) in culture. Moreover, additional assays designed to evaluate endothelial cell function showed that HAEC monolayers obtained on these scaffolds not only maintained LDL uptake activity but also enhanced nitric oxide release and elevated laminin 1 and collagen IV deposition. These results suggest that this new scaffold provide a better physiological substrate for endothelial cell culture and suggest its further application for biomedical research, cancer biology and regenerative biology.

Micron-scale spatially patterned, covalently immobilized vascular endothelial growth factor on hydrogels accelerates endothelial tubulogenesis and increases cellular angiogenic responses.

Spontaneous formation of endothelial tubules was restricted to patterned micron-scale regions presenting cell adhesion ligands and angiogenic signaling protein on poly(ethylene glycol) hydrogels. Arginine-glycine-aspartic acid-serine (RGDS), an integrin ligand, and vascular endothelial growth factor (VEGF), a rate-limiting signaling protein involved in angiogenesis, were covalently bound through photopolymerization via laser scanning lithography to the surface of poly(ethylene glycol) hydrogels in patterned micron-scale regions. Endothelial cells cultured in this restricted environment underwent accelerated tubulogenesis, forming endothelial tubes within 2 days, whereas cells cultured on larger patterned areas remained spread and did not form tubules by day 2. Tubules formed in 2 days on RGDS and VEGF patterns were observed to possess lumens; however, tubule-like structures formed in 2 days on RGDS-only control patterns did not have observable lumens. Additionally, tubules that formed on restricted areas of RGDS and VEGF expressed more VEGF receptor 1, VEGF receptor 2, and ephA7 surface markers, in addition to higher expression of laminin, than cells remaining spread on wide patterned lines. This work reports spatial control and acceleration of endothelial tubule formation using biocompatible hydrogel materials to allow the formation of highly organized vascularized tissues.

Bioactive hydrogels made from step-growth derived PEG-peptide macromers.

Synthetic hydrogels based on poly(ethylene glycol) (PEG) have been used as biomaterials for cell biology and tissue engineering investigations. Bioactive PEG-based gels have largely relied on heterobifunctional or multi-arm PEG precursors that can be difficult to synthesize and characterize or expensive to obtain. Here, we report an alternative strategy, which instead uses inexpensive and readily available PEG precursors to simplify reactant sourcing. This new approach provides a robust system in which to probe cellular interactions with the microenvironment. We used the step-growth polymerization of PEG diacrylate (PEGDA, 3400Da) with bis-cysteine matrix metalloproteinase (MMP)-sensitive peptides via Michael-type addition to form biodegradable photoactive macromers of the form acrylate-PEG-(peptide-PEG)(m)-acrylate. The molecular weight (MW) of these macromers is controlled by the stoichiometry of the reaction, with a high proportion of resultant macromer species greater than 500kDa. In addition, the polydispersity of these materials was nearly identical for three different MMP-sensitive peptide sequences subjected to the same reaction conditions. When photopolymerized into hydrogels, these high MW materials exhibit increased swelling and sensitivity to collagenase-mediated degradation as compared to previously published PEG hydrogel systems. Cell-adhesive acrylate-PEG-CGRGDS was synthesized similarly and its immobilization and stability in solid hydrogels was characterized with a modified Lowry assay. To illustrate the functional utility of this approach in a biological setting, we applied this system to develop materials that promote angiogenesis in an ex vivo aortic arch explant assay. We demonstrate the formation and invasion of new sprouts mediated by endothelial cells into the hydrogels from embedded embryonic chick aortic arches. Furthermore, we show that this capillary sprouting and three-dimensional migration of endothelial cells can be tuned by engineering the MMP-susceptibility of the hydrogels and the presence of functional immobilized adhesive ligands (CGRGDS vs. CGRGES peptide). The facile chemistry described and significant cellular responses observed suggest the usefulness of these materials in a variety of in vitro and ex vivo biologic investigations, and may aid in the design or refinement of material systems for a range of tissue engineering approaches.