External-beam radiotherapy in the management of carcinoma of the prostate

Improved Cryosurgery by Use of Thermophysical and Inflammatory Adjuvants

In the present article, recent research efforts in our laboratory to improve cryosurgery by use of mechanistically derived adjuvants are reviewed. Our research has been focused on enhancing two freezing induced injury mechanisms - i) direct cell injury by use of thermophysical adjuvants, and ii) vascular injury by use of an inflammatory adjuvant. The thermophysical adjuvants are chemicals, usually salts, which can induce secondary crystallization, called eutectic solidification, in a cryolesion; thereby enhancing direct cell injury. The inflammatory adjuvant is a cytokine, tumor necrosis factor-alpha (TNF-α), which upregulates inflammation of microvasculature in tumors prior to freezing to promote vascular injury in the cryolesion. Even though the individual mechanism of injury enhancement within the cryolesion of each adjuvant requires further study, both adjuvants are envisioned to enlarge the complete killing zone so that the boundary of the cryolesion matches more closely with the edge of ice-ball. By bringing the edge of the cryolesion closer to the edge of iceball, the adjuvants hold promise for improvement of image guidance and outcome of cryosurgery.

Pudendal nerve injury in men with fecal incontinence after radiotherapy for prostate cancer

BACKGROUND

The precise etiology of fecal incontinence (FI), which occurs frequently following external beam radiotherapy (EBRT) for prostate carcinoma is unknown. It is possibly related to pelvic nerve injury. The aim of this study was to assess the incidence of pudendal nerve dysfunction in men with FI after EBRT for prostate cancer compared to men with FI but no history of EBRT.

MATERIAL AND METHODS

Data were evaluated from 74 men with intact anal sphincters on endo-anal ultrasound (17 post-EBRT) who had been investigated for FI at a tertiary center. Wexner incontinence scores, pudendal nerve function, anorectal manometry, and rectal sensitivity were compared between the two patient groups.

RESULTS

Post-radiotherapy patients were older (77±6 vs. 62±17 years, p<0.005) and had worse incontinence than those with no history of radiotherapy (Wexner score; 13±3 vs. 8±4; p<0.005). Bilateral pudendal nerve terminal motor latency (PNTML) was abnormal in 87% of radiotherapy versus 22% of non-radiotherapy patients (p<0.001) and the significant difference persisted even after correction for age differences. Anal sphincter pressures and rectal sensitivity for both groups were similar.

CONCLUSION

There is a markedly higher incidence of pudendal nerve dysfunction in men with FI after EBRT for prostate cancer compared with men with FI from other etiologies. The increased severity of incontinence in radiotherapy patients is not matched by alterations in either anal sphincter pressures or rectal sensitivity compared to FI in non-ERBT patients.

Prostatic carcinosarcoma 15 years after combined external beam radiation and brachytherapy for prostatic adenocarcinoma: a case report

A 65-year-old man with a history of combined pelvic external beam radiation therapy (EBRT) and brachytherapy for prostatic adenocarcinoma 15 years prior underwent total pelvic exenteration for presumed rectal sarcoma with prostatic invasion. Pathology revealed carcinosarcoma of prostatic origin. This patient exhibited the longest reported interval between initial presentation with prostatic adenocarcinoma and development of carcinosarcoma. This case is also the first reported case of prostatic carcinosarcoma occurring after combined EBRT and brachytherapy. The increasing use of such combination high-dose radiation therapy may potentially lead to an increased incidence of secondary malignancies such as prostatic carcinosarcoma in the future.

Differential expression of steroid receptors in prostate tissues before and after radiation therapy for prostatic adenocarcinoma

The expression, distribution and the role of steroid receptors in benign and malignant untreated prostate tissues is well recognized, however, the status of steroid receptors in prostate after radiotherapy (RT) for adenocarcinoma has not yet been studied fully. Immunohistochemical evaluation of androgen receptor (AR), estrogen receptor-alpha (ER-alpha), estrogen receptor-beta (ER-beta), and progesterone receptor (PR) was carried out in prostate needle biopsies obtained before and after radiotherapy from 60 patients with adenocarcinoma. The ER-beta transcripts were also studied by RT-PCR in LNCaP prostate carcinoma cell line before and 24 hr after gamma-irradiation at 0.5 Gy and 8.0 Gy. Significantly higher level of ER-beta expression was found in post-radiation samples of prostate adenocarcinoma and benign epithelium. After RT, all steroid receptors were upregulated in prostatic stroma. Tumor AR expression did not change significantly. Although a positive association between AR and ER-beta expression was observed in pre-treatment prostate adenocarcinoma, it was lost after RT suggesting that these 2 steroid receptors respond differently to RT. High levels of pretreatment tumor ER-beta were associated with local recurrence after RT and decreased biochemical recurrence-free survival (p = 0.028). LNCaP cell line that expressed no ER-beta mRNA before gamma-irradiation, clearly expressed ER-beta mRNA 24 hr after 0.5 Gy and 8.0 Gy. Upregulation of all steroid receptors in the prostate stroma and upregulation of ER-beta in the tumor epithelium after RT, may represent a protective tissue response to radiation-induced tissue injury. Although stromal AR was doubled after RT, the tumor and benign epithelium expression of AR seemed resistant to change by RT.