Predictors and Prevalence of Nodal Disease in Salvage Oropharyngectomy.

BACKGROUND: Patients with recurrent oropharyngeal cancer often require extensive salvage surgery. For patients with clinically N0 necks, the indication for concurrent neck dissection remains unclear. This study aimed to determine predictors, prevalence, and distribution of nodal disease in patients treated with salvage oropharyngectomy. METHODS: In a case series with data collection at a single tertiary academic National Cancer Institute (NCI)-designated comprehensive cancer center, this study analyzed patients treated with prior radiation or chemoradiation who had persistent, recurrent, or second primary squamous cell carcinoma of the oropharynx requiring oropharyngeal resection between 1998 and 2017 (n = 95). Clinical and oncologic characteristics and treatment outcomes were collected, and statistical analyses were performed. RESULTS: The overall rate of nodal positivity was 21% (24/95), and the rate of occult nodal disease was 6% (4/65). Ipsilateral and contralateral level 2 were the most common areas harboring positive nodes. Bivariate analysis showed female sex (p = 0.01), initial overall stage (p = 0.02), and N status (p = 0.03), as well as recurrent overall and T stage (p = 0.05) to be predictors of nodal disease. In the multivariate analysis, recurrent T stage continued to be significantly predictive of pathologic nodal disease. Both computed tomography (CT) and positron emission tomography-CT were moderately accurate in predicting nodal disease in the salvage setting (area under the curve, 0.79 and 0.80, respectively). CONCLUSION: Occult nodal disease is observed in few patients undergoing salvage oropharyngeal resection. This study identified factors predictive of nodal disease in patients undergoing salvage oropharyngectomy and appropriate diagnostic tests in this setting.

Supplementation of collagen scaffolds with SPARC to facilitate mineralization.

The extracellular matrix-associated protein, SPARC (Secreted Protein Acidic and Rich in Cysteine) is known to play a role in the mineralization of collagen in bone formation. The objectives of this study were to determine: 1) if SPARC supplementation of type 1 collagen scaffolds in vitro facilitated the binding of pre-formed HA nanoparticles added to the scaffolds; 2) if SPARC supplementation of the scaffolds enhanced the uptake of calcium and phosphorus from calcium phosphate solutions; and 3) if pretreatment in a calcium phosphate solution enhanced the subsequent binding of the nanoparticles. A related objective was to begin to determine the behavior of mesenchymal stem cells in the scaffolds when the constructs were grown in osteogenic medium. The calcium and phosphorus contents of the scaffolds were evaluated by inductively coupled plasma analysis, and the elastic modulus of the scaffolds determined by unconfined compression testing. Scaffolds were seeded with goat bone marrow-derived mesenchymal stem cells and the cell-seeded constructs grown in osteogenic medium. Supplementation of the scaffolds with as little as 0.008 % SPARC (by wt. of collagen) resulted in an increase in the binding of hydroxyapatite nanoparticles to the scaffold, but had no effect on incorporation of calcium or phosphorus from a calcium phosphate solution. The incorporation of hydroxyapatite nanoparticles into the scaffolds did not result in an increase in modulus. Supplementation of the scaffolds with SPARC and the increase in the binding of hydroxyapatite nanoparticles did not affect the proliferation of mesenchymal stem cells.

Outgrowth of chondrocytes from human articular cartilage explants and expression of alpha-smooth muscle actin.

The objectives of this study were to investigate the effect of various enzymatic treatments on the outgrowth of chondrocytes from explants of adult human articular cartilage and the expression of a specific contractile protein isoform, alpha-smooth muscle actin, known to facilitate wound closure in other connective tissues. Explants of articular cartilage were prepared from specimens obtained from patients undergoing total joint arthroplasty. The time to cell outgrowth in vitro was determined and the expression of alpha-smooth muscle actin shown by immunohistochemistry. Treatment of the explants with collagenase for 15 minutes reduced the time to outgrowth from more than 30 days to 3 days. Hyaluronidase, chondroitinase ABC, and trypsin applied for the 15-minute period had no effect on the time to cell outgrowth when compared with untreated controls. Pretreatment with hyaluronidase prior to collagenase reduced the time to outgrowth. A notable finding of this study was that the majority of chondrocytes in the adult human articular cartilage specimens and virtually all of the outgrowing cells contained alpha-smooth muscle actin. We conclude that human articular chondrocytes have the capability to migrate through enzymatically degraded matrix and express a contractile actin isoform. Collagenase treatment reduces the time required for cell outgrowth.