Importance:
Using prospective registry data, the investigators recently replicated their published ‘use it or lose it’ analysis (2013) confirming independent benefit of EAT and swallowing EXERCISE adherence during radiotherapy (RT) on oral intake outcomes. In a contemporary cohort of patients with oropharyngeal cancer (OPC) treated with RT, functional benefit of two pharyngeal activities performed by patients was confirmed: those who maintained PO (oral intake; EAT) and/or self-reported adherence to swallowing EXERCISE were more likely to eat solid foods by 3-6 months after treatment, while patients who EAT during RT expectedly had the shortest feeding tube dependence. 

Objective:
To extend the previous work by examining the relationship of EAT and EXERCISE using validated, clinician-graded (per videofluoroscopy) and patient-reported swallowing outcomes.

Design: Secondary analysis of the prospective oropharynx registry.

Setting: Single institution comprehensive cancer center.

Participants: 595 patients treated with primary RT (19%, 111) /chemoradiation (CRT; 73%, 434) or primary transoral robotic surgery (TORS)+RT/CRT (8%, 50) for OPC.

Interventions or Exposures: Primary exposure variables included (1) EAT: oral intake status at end of RT (nothing by mouth/NPO; partial PO [PO with tube supplement]; full PO); and (2) swallow EXERCISE adherence (non-adherent vs partial/full adherence) during RT.

Main Outcomes: Clinician-graded dysphagia severity grade and prevalence (per the videofluoroscopic Dynamic Imaging Grade of Swallowing Toxicity; DIGEST) and patient-reported MDADI were prospectively collected at baseline and 3-6 months post-RT. Multiple linear regression, ordinal, and logistic regression models were analyzed adjusting for tumor location, baseline dysphagia, chemotherapy, N and T stage.  

Results: At the end of RT, 9% of patients were NPO (55), 19% partial PO (115), 71% full PO (425) and 57% (340) reported adherence to swallow exercises. In univariate models, composite MDADI was significantly associated with EAT at baseline (β=2.79, 95%CI:1.07-4.51, p=0.002) and 3-6 months (β=6.28, 95%CI:4.24-8.32, p<0.001; mean MDADI±SD: NPO:73±12; partial PO:73±17; full PO:83±13) and with EXERCISE at 3-6 months (β=4.18, 95%CI:1.39-7, p=0.003; mean MDADI±SD: non-adherent:77±16; adherent:82±14). After multivariate adjustment, MDADI associations with EAT were maintained (β=6.25, 95%CI:1.49-11, p=0.01) while EXERCISE was not (β=2.27, 95%CI:-0.46-5, p=0.1). Moderate-severe dysphagia (per videofluoroscopy DIGEST grade≥2) prevalence at 3-6 months was lowest in patients who were full PO at the end of RT (DIGEST ≥2: 12%, 54/425; partial PO: 23%, 27/115; NPO: 20%, 11/55; p=0.004) but differences were not identified between EXERCISE adherence groups (non-adherent: 16%, 42/255; adherent: 15%, 50/340, p=0.52). In univariate models, DIGEST associated with EAT at baseline (OR:0.75, 95%CI:0.57-0.99, p=0.04) and 3-6 months (OR: 0.56, 95%CI:0.4-0.8, p<0.001) but this was not maintained in multivariate modelling (EAT OR:0.58, 95%CI:0.27-1.23, p=0.16).

Conclusions: These prospective registry data further extend findings of prior work that support independent benefit of EAT and swallowing EXERCISE adherence during RT, now supported with broader domains of swallowing function using validated swallow outcome measures. Different patterns of benefit were seen depending on the outcome measure with results herein supporting better swallow-related QOL at 3-6 months among patients who EAT independent of their EXERCISE adherence, but not visa versa.