Session Item

The study Prostate Radiotherapy Integrated with simultaneous MRI (PRISM-OUH) was initiated to assess feasibility and tolerability of online adaptive radiotherapy on the 1.5 T MR-linac (oMRgRT) for patients with localized prostate cancer (intermediate risk). To achieve the complete picture of tolerability, the aim of the present study was to describe the development in patient-reported outcomes (PROs) over a six months period following oMRgRT. 

For patients with prostate cancer, oMRgRT was delivered in 20 fractions with daily online adaptation. Radiotherapy (RT) was planned to a total dose of 60 Gy in the prostate and proximal 1 cm of the seminal vesicles (SV), and 48 Gy to an additional 1 cm of the SV.  PTV margins were 5 mm isotropic, except for 3 mm posteriorly for PTV 60 Gy. To assess patient symptoms and HRQoL, the patients reported the International Prostate Patient Index (I-PSS, lower score=lower symptom burden) and the Expanded Prostate Cancer Index (EPIC-26, higher score=better HRQoL) at baseline, end of RT, and one, three and six months after end of RT. In addition, HRQoL was assessed with the EUROQOL EQ-5D-5L (1=max HRQoL) at the same time points.   

In total, 31 patients were included; median age 69 (46-76), Gleason score 6 (n=4) and 7 (n=27), 78% had ECOG/WHO performance status 0, and 48% received six months of LHRH agonists. Out of 620 planned treatment fractions, 26 were delivered on a CT-based linac (15 to one patient finding the treatment time hard to tolerate, 11 due to technical problems).

Moderate/severe urinary symptoms was reported by 74% of the patients at the end of RT (highest mean I-PSS score 13.6). This score was still above the pre-treatment level (6.5) one month following RT (11.3). Three months following RT, the same proportion of patients with moderate/severe urinary symptoms as pre-treatment (30%) was obtained (Table 1). These findings were consolidated in the EPIC-26 domain scores. In three domains (urinary incontinence, urinary irritative /obstructive and sexual), the pre-treatment summary score was not reached until three months following RT (Table 2). Pain or burning on urination was one of the symptoms worsened one month after RT (15% vs 3% baseline).

Patient satisfaction with their urinary condition reached the pre-treatment level one month after RT (Table 1). The HRQoL of the patients was stable throughout oMRgRT (EQ index score 0.907) and improved one and three months following RT (0.911-0.951).

Patients with localized prostate cancer reported some acute urinary toxicities and sexual problems still being increased one month following oMRgRT but reduced to the pre-treatment level at three months following oMRgRT. However, an increased HRQoL was reported after the end of oMRgRT. The acute symptom trajectory outside the fixed time-points remains to be investigated, thus a prospective study with weekly PROs is initiated.