Aspiration Pneumonia and Pneumonitis

Among HNSCC patients, the etiology of aspiration, pneumonia, and pneumonitis is multifactorial and remains an important and often under-recognized source of morbidity and mortality during and following completion of treatment. In a retrospective analysis of 374 patients who received organ preservation therapy for locally advanced HNSCC, risk factors for aspiration pneumonia included poor oral hygiene, advanced N-classification, inpatient treatment, and hypoalbuminemia.65 Treatment breaks occurred far more often in patients with aspiration pneumonia versus those without (36% vs. 3%, respectively; p < 0.01), which ultimately affected survival (Table 1).65 Kawai et al. reported similar findings and found that 21% (65 of 305) of patients developed pneumonia at a median of 161 days following treatment; chronic alcohol consumption, poor oral hygiene, hypoalbuminemia, coexisting malignancies (mainly esophageal and gastric cancer), and use of sleeping pills were independent predictors.66 Rates of post-treatment pneumonia range from 5 to 25%, with concurrent CRT having the largest influence on its development in most studies.5,6,65-72The sequela can be devastating with 30-day mortality rates of 20 to 30%.24,73-75 The range in incidence of pneumonia among studies could partly be explained by patient demographics and length of follow up. In a retrospective study of 15,894 Taiwanese patients with HNSCC by Chu et al., the authors reported a lower incidence of pneumonia (5%) within 90 days of RT initiation.67 However, only 15% of the cohort was older than age 65, in contrast to studies with a higher proportions of elderly patients.65-67
While the risk of pneumonia in patients treated with CRT is significantly elevated during and soon after treatment, this risk continues to be elevated several years after therapy.6,75 In an analysis of 3,513 patients, Xu et al. found that nearly one-quarter of elderly patients developed aspiration pneumonia within 5 years of CRT, with a 1 year and 5 year cumulative incidence of 15.8% and 23.8% for patients with head and neck malignancies, compared to 3.6% and 8.7% for noncancer controls, respectively.75 A 42% increased risk of death was also observed (p < 0.001) after controlling for confounding factors. The authors showed that independent risk factors for aspiration pneumonia included hypopharyngeal and nasopharyngeal tumors, increased comorbidities, older age at diagnosis, and treatment at a teaching hospital.
Notably, both of the studies from Xu et al.75 and Chu et al.67 separately identified an increased risk of aspiration pneumonia among patients receiving care at a teaching institution. This finding likely reflects a higher concentration of sicker patients with a higher degree of medical complexity at academic teaching institutions. This is important to note as many of our HNSCC population will undergo treatment at higher volume, academic centers burdened by the COVID-19 pandemic.