Vienna, Austria

ESTRO 2023

Session Item

Urology
6018
Poster (Digital)
Clinical
Assessing the Toxicity After Moderately Hypofractionated Whole Pelvis Radiotherapy
Matthias Moll, Austria
PO-1543

Abstract

Assessing the Toxicity After Moderately Hypofractionated Whole Pelvis Radiotherapy
Authors:

Matthias Moll1, Gregor Goldner1

1Medical University of Vienna, Radiation Oncology, Vienna, Austria

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Purpose or Objective

The objective of this study was the comparison of acute gastrointestinal (GI) and genitourinary (GU) toxicity, as, well as late GI and GU toxicity after moderately hypofractionated (HF) or conventionally fractionated (CF) primary whole pelvis radiotherapy (WPRT).

Material and Methods

Patients with primary prostate cancer treated between 2009 and 2021 were investigated. Applied doses were either 60 Gy in 3 Gy per fraction to the prostate and 46 Gy in 2.3 Gy to the whole pelvis (VMAT technique), or 78 Gy in 2 Gy per fraction to the prostate and 50/50.4 Gy in 1.8 to 2 Gy per fraction (VMAT or IMRT technique) to the whole pelvis. Acute and late GI and GU toxicities according to RTOG were assessed.

Results

106 patients treated with HF and 157 patients treated with CF were included. Median follow-up in the HF and the CF group was 12 and 57 months, respectively. Regarding acute GI toxicity, grade 0 was reported in 13.3 % (HF) vs. 6.4 % (CF), grade 1 in 40.0 % vs. 54.8 %, grade 2 in 46.7 % vs. 37.6 % and grade 3 in 0 % vs. 1.3 % showing no significant difference (p = 0.71). Regarding acute GU toxicity, grade 0 was reported in 20 % (HF) vs. 10.8 % (CF), grade 1 in 57.1 % vs. 57.3 %, grade 2 in 20.0 % vs. 31.8 %, and grade 3 in 2.9 % vs. 0 %, showing a significant difference in favor of HF (p = 0.04). The maximal rate of late GI toxicity was grade 0 in 76.4 % (HF) vs. 61.8 % (CF), grade 1 in 16.0 % vs. 21.7 %, grade 2 4.7 % vs. 13.8 %, and grade 3 1.9 % vs. 2.6 %. The maximum rate of late GU toxicity was grade 0 in 62.3 % (HF) vs. 45.4 % (CF), grade 1 in 26.4 % vs. 26.3 %, grade 2 in 11.3 % vs. 23.0 %, and grade 3 0 % vs. 5.3 %. However, as follow-up time differs between both groups, we compared late GI and GU toxicity between both groups after 3, 12, and 24 months and did not find any significant differences (p = 0.59, 0.22 and 0.71 for GI toxicity and 0.39, 0.58, and 0.90 for GU, respectively).


Table 1: Maximum Acute Gastrointestinal and Genitourinary Toxicity after moderate hypofractionation (HF) and conventional fractionation (CF).


Acute Toxicity

Gastrointestinal    


Genitourinary



HF

CF

HF

CF

RTOG grade 4

0.0 %

0.0 %

0.0 %

0.0 %

RTOG grade 3

0.0 %

1.3 %

2.9 %

0.0 %

RTOG grade 2

46.7 %

37.6 %

20.0 %

31.8 %

RTOG grade 1

40.0 %

54.8 %

57.1 %

57.3 %

RTOG grade 0

13.3 %

6.4 %

20.0 %

10.8 %

P = 0.71 and 0.04 for gastrointestinal and genitourinary toxicity, respectively. N = 105 for HF and 157 for CF

Conclusion

Moderately hypofractionated WBRT seems to provide a well-tolerated treatment of the pelvic lymph nodes within the first 2 years. Longer follow-up and CRTs are needed to provide further evidence.