ICHNO-ECHNO 2022 - Abstract Book

S20

ICHNO-ECHNO 2022

Results The 6- and 7-week groups were well balanced; by comparison patients in the 4-week radiotherapy group were less fit with a reduced ECOG PS, more co-morbidity, were more likely to be smokers and have p16-negative disease (p < 0.01). LRC did not differ across all three groups (p = 0.78, log-rank test), but OS was worse in the 4-week group than in the 6-week and 7- week groups (p < 0.01) (Figure 1). Rates of enteral tube use for feeding were similar between the 6- and 7-week groups both during (47% vs 59%, p = 0.08) and at one year post radiotherapy (10% vs 6%, p = 0.27). Compared to the 6- and 7-week groups, rates were higher in the 4-week group both during (74%, p < 0.01) and after (18%, p = 0.07) radiotherapy. As the number of patients alive and cancer free in the 4-week group was low (n = 11 of 39), MDADI questionnaires were only sent to patients in the 6- and 7-week groups. 107 patients returned evaluable MDADI questionnaires (39% of the cohort, 71% response rate). In surviving patients, there was no significant difference was observed between the 6- and 7-week radiotherapy groups for median global (63.6 vs 63.6, p = 0.99), mean composite (66.4 vs 63.2, p = 0.41) or sub-scale scores (Figure 2). Figure 1

Figure 2

Conclusion For patients with OPSCC, swallowing outcomes appear equivalent for mildly accelerated, hypofractionated and standard fractionation radiotherapy, supporting the use of the former as a standard of care. Disease control is similar across all groups, as expected given the corresponding biological effective doses (BED 10 67.5 Gy, 68.6 Gy and 67.5 Gy respectively). For moderate hypofractionation, OS was worse, perhaps due to a less-fit patient demographic but this also raises concern