Androgen Deprivation and Late Rectal Bleeding after Radiotherapy for Prostate Carcinoma

English

Reviewer: William Levin, MD
OncoLink
Ultima Vez Modificado: 11 de octubre del 2002

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

Background

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.

Materials and Methods

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 %.

Results

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.

Author's Conclusions

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.

Clinical/Scientific Implications

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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