1011 Palladium-103 brachytherapy for clinical T1T2 prostate carcinomas

Proceedings

of the 39th

Annual

ASTRO

Meeting

22

1011 PALLADIUM-103 Dattoli,

MJ, Wallner,

University

Community

Purpose:

To evaluate

BRACHYTHERAPY KB*,

Cash

Hospital,

FOR CLINICAL

JC, Ross, RF. Koval,

Tl/T2 JM, Sorace,

‘Tampa, FL and *Memorial

the efficacy

of Pd-103

brachytherapy

PROSTATE

CARCINOMAS

IL4

Sloan-Kettering

Cancer

Center,

as sole modality

for patients

NYC

having

clinical

TliT2

prostate

carcinomas

Materials and Methods: The initial 103 consecutive patients treated at OUT hospital are available for biochemical failure and toxicity data following Pd-103 brachytherapy. Minimum peripheral target dose of 11,500&y (median) was prescribed. Follow-up range: 4-6 years (56 months median). Mean pre-treatment PSA = 11.7ngiml. All patients have been followed in prospective fashion with respect to PSA response, clinical evidence of die progression and complications. Criteria for biochemical failure was relatively strict, and was analyzed using PSA>l .O. Patients whose PSA was still decreasing at last follow-up were censored at that time. Freedom horn failure rates were calculated by the method of Kaplan and Meier. Differences between groups were determined by the Log-rank method. Sexual potency was de&ted as the ability to attain and maintain an erection sufficient for intercourse. Results: ulceration

Actuarial heedom or incontinence

horn biochemical failure at 6 years after treatment (despite 16 pts having prior TURP). The impotency

is 68%. Toxicity rate is 12%.

has been low with no patient

developing

rectal

Of the 33 pts with a post treatment PSA >l.O, 29 pts actually had one or more adverse features determined to be PSA>lO (26 pts), Gleasons score > 7 (5 pts), AJC clinical stage T2b (10 pts). Mean pre-treatment PSA’s of the 33 failures = 183ng/ml. For the 74 pts without high risk features, the actuarial 6 years biochemical heedom from progression rate using PSA4 .O as an endpoint for snccess is 93%. Conclusion: This biochemical geedom horn progression rate compares favorably to other brachytherapy as sole modality in properly selected patients. Morbidity has been relatively in patients having PSA
modalities and supports the use of Pd-103 low. Pd-103 implant alone is currently beiig

used

1012 DOSE

RESPONSE

FOR

IODJNE

- 125 PROSTATE

Richard Mount

G. Stock. Nelson N. Stone. Andrea Tabert. Sinai School of Medicine. New York. NY

IMPLANTS J. Keith

Dewyngaert

Objective: No dose response study has ever been performed for l-125 prostate implants using modern techniques of implant evaluation and modern treatment outcome endpoints. Using an interactive ultrasound guided technique and post-implant dosimetry, we have increased the amount of activity implanted per volume over time. This has resulted in different delivered dose levels, This study explores the relationship between dose. biochemical failure and biopsy results. Materials and Methods: 121 patients with Tl - T2 prostate cancer were implanted with l-125 radioactive seeds and followed from 6 to 67 months (median - 25) post-implant. No patient received external beam irradiation or hormonal therapy. All patients implanted with I-125 had Gleason scores 16 Presenting PSA levels ranged from 1.9 - I89 rig/ml (median - 7.6 rig/ml). One month post-implant a CT based three dimensional dosimetric evaluation was performed on all patients. Using TG43 guidelines, dose volume histograms were calculated. The dose delivered to the gland was defined as the D90 (dose delivered to 90% of prostate tissue as defined by CT). The D90s ranged from 26.8 to 229.8 Gy (median - 136.9 Gy). Biochemical failure was defined as 2 consecutive rises in PSA or a nadir level above 1.0 ngiml. Post-treatment prostate biopsies (6 core samples) were routinely performed at 2 years post-implant. Results: A dose response WEIS found at a D90 of 140 Gy. Patients receiving a D90 ~140 Gy (65 pts) were similar with respect to presenting disease prognostic factors to those receiving a D90 3 140 Gy (56 pts). PSA levels 510 &ml vs. >lO rig/ml were seen in (60% vs. 40%) and (68% vs. 32%) for the low dose and high dose groups, respectively. Stages were Tlb-T2a vs. T2b-T2c in (48% vs. 52%) and (57% vs. 43%) for the low and high dose groups, respectively. Low grade lesions (score 2-4) were seen in 40% and 23% of low dose and high dose groups, respectively. Moderate grade lesions (score 5- 6) were seen in 60% and 77% of low dose and high dose groups, respectively. Patients receiving a D90 ~140 Gy had an actuarial freedom from biochemical failme (FBF) at 4 years of 59% compared to a rate of 93% for those receiving a D90 >140 Gy (p=O.O3). Two year posttreatment biopsies were negative in 72% (29/40) of patients with a D90 < 140 Gy compared to a rate of 93% (14/I 5) in patients with a DSO>l40 Gy (p=O.O9). This dose response was more pronounced in patients presenting with PSA levels > 10 rig/ml. In these patients, the 4 year FBF rates were 51% and 100% for the low and high dose groups, respectively (p=O.O4). In patients with presenting PSA 510 rig/ml, the 4 year FBF rates were 66% and 89% for the low and high dose groups. respectively (p=O.29). Conclusion: A dose response was observed at a level of 140 Gy. Adequate I -125 implants 140 Gy to the D90. Longer follow-up with more patients is needed to assess dose response

should be considered those delivering levels above 140 Gy.

a minimum

of