Dose Escalation with High Dose Rate Brachytherapy or Protons in Curative Radiotherapy of Prostate Cancer

• The aim of the thesis was to study the outcome and side effects after dose-escalated radiotherapy with high dose rate brachytherapy (HDR-BT) or proton beam therapy (PBT) boost in prostate cancer.The first cohorts of men in Sweden treated with either HDR-BT or PBT in combination with conventional photon beam therapy (2 Gray (Gy) fractions to 50 Gy) were analysed. The HDR-BT was given with two 10 Gy fractions, and the PBT with four fractions of 5 Gy. The analyses included 823 men in two HDR-BT cohorts, and 265 men in the PBT cohort. A large proportion of the cohorts, from 38% to 53%, were classified as high risk. After a follow-up between four and eleven years, both combinations showed low risks for relapse. The overall 5-year risk for PSA relapse was 0% for men with low risk. After PBT, the 5-year PSA relapse risk for intermediate and high risk were 5% and 26% respectively. After HDR-BT the 10-year risks for PSA relapse were 0%, 21% and 33% for low, intermediate, and high risk, respectively.The risk for early and late toxicity was low. Genitourinary (GU) toxicity was more frequent than gastrointestinal (GI) toxicity. GU toxicity may have a late onset and progress slowly with time after HDR-BT. The 5- and 10-year actuarial incidences of urethral stricture were 6% and 10% respectively after HDR-BT. With applied dose constraints to the urethra the 10-year risk was 5%. The actuarial prevalence of GI toxicity declined slowly with time after HDR-BT as well as after PBT.A PSA bounce after HDR-BT was seen in 26% of the patients, more frequent with younger age and lower Gleason score, and followed by a low risk for relapse.For dose-escalated radiotherapy with HDR-BT or PBT:long-term tumour control was achieved, not only for low- and intermediate risk, but also for the majority of high risk patients,a PSA bounce after HDR-BT was folled by a good prognosis,levels of late toxicity were low,genitourinary toxicity was more frequent than gastrointestinal toxicity,dose constraints to risk organs must be applied to minimise risks for late toxicity.

Ämnesord

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Cancer och onkologi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Cancer and Oncology (hsv//eng)

Nyckelord

Prostate cancer

radiotherapy

brachytherapy

high dose rate

protons

PSA bounce

Publikations- och innehållstyp

vet (ämneskategori)

dok (ämneskategori)