[攝護腺癌] 近接治療相關整理

攝護腺癌近接治療(brachytherapy) 在台灣放射治療領域裡面不常被使用, 但是據筆者了解, 還是有醫院曾經或者目前還在進行這方面的治療, 由於這方面在基礎以及臨床上都有其重要性, 因此這邊來做個整理

使用時機

1. very low risk group: expected life expectancy > 20 years, NCCN 是建議active surveillance 為主, 但是還是可以考慮病人接受EBRT or Brachytherapy or 手術

2. low risk group: expected life expectancy > 10 years, NCCN 是建議active surveillance 為主, 但是還是可以考慮病人接受EBRT or Brachytherapy or 手術

3. favorable intermediate risk: 不管expected life expectancy 多少, 都可以考慮做Brachytherapy alone, 當然其他治療也是選項

4. unfavorable intermediate risk: 不管expected life expectancy 多少, 都可以考慮做EBRT + Brachytherapy +/- ADT(4-6momths), 當然其他治療也是選項

5. high or very high risk:  expected life expectancy > 5 years or 有症狀, 可以考慮做EBRT + Brachytherapy(1-3 years) +/- ADT(1-3 years), 當然其他治療也是選項

使用射源:

這裡依照NCCN guideline 建議, 列出使用射源以及劑量:

brachytherapy alone: 適用於very low risk, low risk 以及 favorable intermediate risk

LDR brachytherapy
I-125	145Gy
PD-103	125Gy
CS-131	115Gy
HDR brachytherapy
Ir-192	13.5 Gy x 2 implants 9.5 Gy BID x 2 implants

EBRT + brachytherapy: 適用於unfavorable intermediate risk, high risk 以及 very high

(EBRT: 45–50.4 Gy/25–28 fx or 37.5 Gy/15 fx)

LDR brachytherapy
I-125	110-115Gy
PD-103	90-100Gy
CS-131	85Gy
HDR brachytherapy
Ir-192	15 Gy x 1 Fx 10.75 Gy x 2Fx

相關臨床試驗

1. RTOG0232: 目前主要的結果發表在ASTRO2016(survival & toxicity)以及ASTRO2018(patient report outcome), 主要是想研究在clinical stage T1c-T2b and either Gleason Score (GS) 2-6/PSA 10-20 or GS 7/PSA <10 的 prostate cancer 病人, EBRT + brachytherapy versus brachytherapy, 結果發現5-year PFS (95% CI) was 85% (80, 89) for the EBT + B arm and 86% (81, 90) for the B arm (HR = 1.02, futility P = 0.0006 => 表示兩個arm差不多), acute toxicity 兩個arm 差不多, 但是 late toxicity>=G2 以及 late toxicity >= grade 3, EBRT + B 組明顯比較多; patient report outcome showed addition of EBT to B resulted in poorer urinary, bowel, and sexual PROs

=> 結論就是 favorable intermediate risk patient(收進來的病人大部分是FIR) => brachytherapy alone 就已經足夠, 不需要再加上EBRT

2. ASCEND-RT:

發表在 2016 跟 2017 的 red journal, 共收案 398 位男性, with a median age of 68 years; 69% (n=276) had high-risk disease. After stratification by risk group, the subjects were randomized to a standard arm with 12 months of androgen deprivation therapy, pelvic irradiation to 46 Gy, followed by a dose-escalated external beam radiation therapy (DE-EBRT) boost to 78 Gy, or an experimental arm that substituted a low-dose-rate prostate brachytherapy (LDR-PB) boost

結果發現The 5-, 7-, and 9-year Kaplan-Meier b-PFS estimates were 89%, 86%, and 83% for the LDR-PB boost versus 84%, 75%, and 62% for the DE-EBRT boost (log-rank P<.001). The LDR-PB boost benefited both intermediate- and high-risk patient; 副作用方面: The incidence of acute and late GU morbidity was higher after LDR-PB boost, and there was a nonsignificant trend for worse GI morbidity. No differences in the frequency of erectile dysfunction were observed.

結論就是Compared with 78 Gy EBRT, men randomized to the LDR-PB boost were twice as likely to be free of biochemical failure at a median follow-up of 6.5 years; 但是GU toxicity 比較高

ref.

1. NCCN  guideline

2. Khan's physics for radiotherapy

3. Essential of clinical radiation oncology