Temporal patterns of patient‐reported trismus and associated mouth‐opening distances in radiotherapy for head and neck cancer: A prospective cohort study.

Abstract: Objectives: To identify temporal patterns of patient‐reported trismus during the first year post‐radiotherapy, and to study their associations with maximal interincisal opening distances (MIOs). Design: Single institution case series. Setting: University hospital ENT clinic. Participants: One hundred and ninety‐six subjects who received radiotherapy (RT) for head and neck cancer (HNC) with or without chemotherapy in 2007‐2012 to a total dose of 64.6/68 Gy in 38/34 fractions, respectively. All subjects were prospectively assessed for mouth‐opening ability (Gothenburg Trismus Questionnaire (GTQ), European Organization for Research and Treatment of Cancer quality of life Questionnaire (EORTC QLQ‐H&N35), and MIO) pre‐RT and at 3, 6 and 12 months after RT. Main outcome measures: Correlations between temporally robust GTQ symptoms and MIO as given by Pearson's correlation coefficients (<italic>P</italic>_{<italic>r</italic>}); temporally robust GTQ‐symptom domains as given by factor analysis; rates of trismus with respect to baseline by risk ratios (RRs). Results: Four temporally robust domains were identified: <italic>Eating</italic> (3‐7 symptoms), <italic>Jaw</italic> (3‐7), <italic>Pain</italic> (2‐5) and Quality of Life (<italic>QoL</italic>, 2‐5), and included 2‐3 persistent symptoms across all post‐RT assessments. The median RR for a moderate/severe (>2/>3) cut‐off was the highest for <italic>Jaw</italic> (3.7/3.6) and <italic>QoL</italic> (3.2/2.9). The median <italic>P</italic>_{<italic>r</italic>} between temporally robust symptoms and MIO post‐radiotherapy was 0.25‐0.35/0.34‐0.43/0.24‐0.31/0.34‐0.50 for <italic>Eating</italic>/<italic>Jaw</italic>/<italic>Pain</italic>/<italic>QoL</italic>, respectively. Conclusions: Mouth‐opening distances in patients with HNC post‐RT can be understood in terms of associated patient‐reported outcomes on trismus‐related difficulties. Our data suggest that a reduction in MIO can be expected as patients communicate their mouth‐opening status to interfere with private/social life, a clinical warning signal for emerging or worsening trismus as patients are being followed after RT. [ABSTRACT FROM AUTHOR]