Rectal morbidity after permanent prostate brachytherapy with dose escalation to biologic target volumes identified by SPECT/CT fusion.
OBJECTIVE
To evaluate rectal morbidity after dose escalation to biologic target volumes identified by capromab pendetide (ProstaScint) single-photon emission tomography images coregistered with computed tomography (SPECT/CT).


METHODS
Two hundred thirty-nine consecutive patients diagnosed with T1c-T3b NxM0 adenocarcinoma of the prostate were treated with brachytherapy seed implant (SI) dose escalation to SPECT/CT-identified biologic target volumes, from February 1997 through December 2002. Patients received SI (n=150) or external beam radiation therapy plus SI (n=89). Rectal morbidity was evaluated by clinician scoring using the modified Radiation Therapy Oncology Group criteria. The median followup was 47.2 (range 24.8-96.1) months.


RESULTS
The rate of acute Grades I and II toxicity was 29.9% and 3.7%, respectively, and chronic Grade I toxicity was 15.4%, 12.4%, 2.3%, and 1.8% at 1, 2, 3, and 4 years postimplant, respectively. Chronic Grade II toxicities were 1.8%, 1.9%, 1.5%, and 0.9% at 1, 2, 3, and 4 years, respectively. No Grade III rectal toxicity was reported. Chronic Grade IV rectal toxicity was 0.5% and 0.6% at 1.5 and 2.5 years, respectively. Ninety-six percent of patients reported freedom from all rectal toxicity after 3 years.


CONCLUSIONS
Dose intensification to occult tumor targets without increasing rectal toxicity may be achieved using SPECT/CT ProstaScint. Additional research to define the role of molecular imaging in prostate cancer is warranted.
Ellis
Rodney J
RJ
Department of Radiation Oncology, Aultman Hospital, Canton, OH, USA. rellis@aultman.com
Zhou
Hang
H
Kaminsky
Deborah A
DA
Fu
Pingfu
P
Kim
Edward Y
EY
Sodee
D Bruce
DB
Colussi
Valdir
V
Spirnak
John P
JP
Whalen
Christopher C
CC
Resnick
Martin I
MI
D000230:Adenocarcinoma / Q000473:pathology / Q000532:radiotherapy; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D001918:Brachytherapy / Q000009:adverse effects* / Q000379:methods; D005500:Follow-Up Studies; D005769:Gastrointestinal Motility / Q000528:radiation effects*; D006801:Humans; D007457:Iodine Radioisotopes / Q000009:adverse effects; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D010165:Palladium / Q000009:adverse effects; D011446:Prospective Studies; D011471:Prostatic Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D011832:Radiation Injuries / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology; D011874:Radiometry; D011879:Radiotherapy Dosage; D012007:Rectum / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000528:radiation effects*; D015899:Tomography, Emission-Computed, Single-Photon; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D047368:Tumor Burden / Q000528:radiation effects*
D007457:Iodine Radioisotopes; D010165:Palladium