Three-dimensional controlled interstitial hyperthermia combined with radiotherapy for locally advanced prostate carcinoma--a feasibility study.
OBJECTIVE
To perform a feasibility study of three-dimensional spatially controlled interstitial hyperthermia for locally advanced prostate cancer.


METHODS
Twelve patients with prostate cancer (T3NxM0) were treated with conventional external beam radiotherapy and one interstitial hyperthermia treatment. Hyperthermia was delivered with the 27-MHz multielectrode current source (MECS) interstitial hyperthermia technique on an outpatient basis. Guided by transrectal ultrasonography, 12 catheters (range 7-16) were placed in the prostate through a template. Two electrodes per probe were inserted. Thermometry (average 100 sensors) was performed from within the probes for online temperature control. Additional thermometry was done in the prostate, rectum, urethra, and bladder. Reconstruction was done by sonography. Prostate perfusion was estimated from the thermal decay at the end of treatment. The full three-dimensional temperature distribution was calculated.


RESULTS
No toxicities greater than Grade 2 were recorded. A learning curve for implantation, position verification, reconstruction, and temperature simulation was experienced. Perfusion was 47 mL/100 g/min (range 30-65). The average measured temperature was T(90) (90% of the prostate reached a temperature of at least:) 39.9 degrees C and T(50) 44.1 degrees C. The average calculated temperatures were lower: T(90), 39.4 degrees C and T(50), 41.8 degrees C, because the entire prostate was taken into account. The tumor temperatures were T(90), 40.7 degrees C and T(50), 43.0 degrees C. The bladder and rectal temperatures were below the safety limits.


CONCLUSIONS
Multielectrode-current-source interstitial hyperthermia is technically feasible and well tolerated. It was not possible to achieve the goal temperature of 42-43 degrees C because of high perfusion and implantation limitations.
van Vulpen
Marco
M
Department of Radiation Oncology, University Medical Center Utrecht, MS Q00.118, Heidelberglaan 100, 3548 CX Utrecht, The Netherlands. m.vanvulpen@radcl.ruu.nl
Raaymakers
Bas W
BW
Lagendijk
Jan J W
JJ
Crezee
Johan
J
de Leeuw
Astrid A C
AA
van Moorselaar
Jeroen R A
JR
Ligtvoet
Cornelis M
CM
Battermann
Jan J
JJ
D000368:Aged; D003131:Combined Modality Therapy; D004567:Electrodes, Implanted; D005240:Feasibility Studies; D006801:Humans; D006979:Hyperthermia, Induced / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011471:Prostatic Neoplasms / Q000473:pathology / Q000532:radiotherapy / Q000628:therapy*; D018084:Ultrasonography, Interventional