Daily online adaptation reduced acute GI toxicity during hypofractionated prostate radiotherapy

KEY POINTS

• The prospective single-centre cohort included 74 patients with localized prostate cancer, pragmatically allocated by machine availability to daily CBCT-based online adaptive radiotherapy (n=43) or conventional CBCT-guided IGRT (n=31). Both groups received the same moderately hypofractionated treatment and identical PTV margins.
• Baseline characteristics were generally similar, but high- or very-high-risk disease was substantially more common in the oART group: 40.5% versus 9.7% (p=0.03), an important imbalance in this nonrandomized comparison.
• Maximum grade ≥2 GI toxicity occurred in approximately 14% with oART versus 45% with IGRT (p=0.028). By the final treatment week, grade ≥2 GI toxicity was 10% versus 31%, respectively.
• GU toxicity did not show the same benefit. Grade ≥2 GU events occurred in 40% with oART versus 36% with IGRT, with no significant difference in overall GU toxicity distribution.
• Clinically meaningful deterioration in fatigue occurred in 37% versus 74% (p=0.004) and physical functioning in 3% versus 27% (p=0.009) for oART versus IGRT. Role-function deterioration was also lower at 23% versus 48%.
• Mean quality-of-life changes similarly favored adaptation across global health, physical, role and social functioning and fatigue. Mean fatigue score increased by only 1.4 points with oART versus 18.1 points with IGRT.
• Interpretation remains limited by nonrandomized convenience allocation, modest sample size, lack of blinding, single-centre design and absence of fraction-level adaptive dosimetry linked directly to toxicity. Toxicity was also assessed only through the final treatment day rather than the conventional 90-day acute-toxicity window.

CLINICAL TAKEAWAY

SOURCE

Strahlentherapie und Onkologie