Androgen Deprivation and Late Rectal Bleeding after Radiotherapy for Prostate Carcinoma
Presenter: G. Sanguineti
Presenter's Affiliation: Department of Radiotherapy, Istituto Nazionale per lo Studio e la Ricerca sul Cancro, Genova, Italy
Type of Session: Scientific
- Previous studies have suggested that adjuvant androgen deprivation (AAD) is associated with altered rectal toxicity when radiation is used in the treatment of prostate cancer.
- This study looks at the duration of ADD with regards to late rectal toxicity.
- 233 patients were treated with radical or postoperative RT. As part of the treatment 111 patients (48%) received AAD.
- 25 patients (23%) discontinued hormonal treatment within 9 months after the start of RT, while the remaining patients (n = 86, 77%) were kept on long term (> 9 months) AAD.
- Total RT dose was 70-76 Gy.
- Late rectal bleeding was graded according to the RTOG morbidity scoring scale.
- Minimum follow-up was 18 months.
- All pts had 3D treatment planning, and dose volume histograms (DVH) of the rectum were obtained.
- Pts were grouped by percent of rectal volume receiving 50 Gy, with those whose rectal volume received more than 50 Gy (V50) > 58% and those with V50 < 58 %.
- At 18 months after RT, 19 pts had grade 2 or 3 late rectal toxicity (crude incidence: 8.1%).
- The incidence of rectal toxicity increased when AAD was given for longer than 9 months.
- On regression analysis, the presence of acute rectal toxicity, dose >74 Gy, being in the large rectal DVH group, and receiving AAD all were associated with late rectal toxicity.
- Long term (> 9 months) adjuvant androgen deprivation reduces rectal tolerance following radiotherapy for localized prostate carcinoma.
- AAD < 9 months may not be detrimental to rectal tolerance.
- When drawing conclusions from this paper, one must remember that follow-up is relatively short and that the number of pts evaluated is small.
- Nevertheless, this study highlights the dilemma faced by physicians who must determine the duration of AAD in pts being treated for intermediate and advanced stage prostate cancer.
- The length of androgen deprivation must be determined on an individual basis based on patient and tumor factors.
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