Page 130 - New epidemiological and PSMA-expression based paradigms in salivary gland tumors

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Chapter 8
Standardized patient-rated and physician-rated toxicities related to treatment of HNC were prospectively collected at 6, 12, 18 and 24 months after treatment, and were scored using the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire - Head and Neck module (EORTC QLQH&N35) and the Common Terminology Criteria for Adverse Events (CTCAE) version 4.0 scores. Multiple imputation was applied to correct for missing data in the follow-up using the MICE package in R[15]. To analyze the association between RT dose to the tubarial gland areas and patient and physician- rated xerostomia and physician-rated dysphagia, multivariable logistic regression analysis was performed to create association models with and without correction for confounding. A two-tailed P-value <.05 was considered statistically significant. Baseline toxicity and mean RT dose to the parotid and submandibular glands were considered as confounders for xerostomia, while for dysphagia, additionally mean RT dose to the pharyngeal constrictor muscle was considered.
Results
All 100 consecutive patients (99 male, one female; median age 69.5; range 53-84) demonstrated a clearly demarcated bilateral PSMA-positive area on PSMA PET/ CT. It extended from the skull base downward along the posterolateral pharyngeal wall, on the pharyngeal side of the superior pharyngeal constrictor muscle (PCM- superior), with a PSMA-positive mass predominantly overlaying the torus tubarius (Fig.1). The median cranio-caudal length of the detected area was 3.9 cm (range 1.0-5.7 cm). The total tracer uptake in the area of interest determined by visual comparison was on average similar to the uptake in the sublingual glands. This was in line with our earlier quantitative evaluation of tracer uptake in the glands of the head and neck[6]. This was consistently more than the uptake in the palate, which is known to contain a high concentration of minor salivary glands.
The dissected area from human cadavers showed a large aggregate of predominantly mucous gland tissue, with multiple macroscopically visible draining duct openings in the dorsolateral pharyngeal wall (Fig.2). The gland was draped primarily over the torus tubarius, the anatomical structure formed by the cartilage that supports the entrance of the auditory tube. The gland extended caudally to the pharyngeal wall and cranially to Rosenmüllers’ fossa. The gland cells showed almost 100%