Dose escalation in prostate radiotherapy up to 82 Gy using simultaneous integrated boost: direct comparison of acute and late toxicity with 3D-CRT 74 Gy and IMRT 78 Gy.
OBJECTIVE
To compare acute and late toxicity after three-dimensional conformal radiotherapy to the prostate to 74 Gy (3D-CRT) with intensity-modulated radiotherapy to 78 Gy (IMRT 78) and IMRT using simultaneous integrated boost to 82 Gy (IMRT/SIB 82).


METHODS
94 patients treated with 3D-CRT to the prostate and base of seminal vesicles to 74 Gy represented the first group. The second group consisted of 138 patients subjected to IMRT covering the prostate and base of seminal vesicles to 78 Gy. The last group was treated with IMRT using SIB. The prescribed doses were 82 Gy and 73.8 Gy in 42 fractions to the prostate and seminal vesicles. Late toxicity was prospectively scored according to the RTOG/FC-LENT scale.


RESULTS
Acute gastrointestinal toxicity >or= grade 2 occurred in 35.1% of patients treated with 3D-CRT, in 16% subjected to IMRT 78, and in 7.7% receiving IMRT/SIB 82. Acute genitourinary toxicity >or= grade 2 was observed in 26.6% (3D-CRT), 33% (IMRT 78), and 30.7% (IMRT/SIB 82). At 3 years, the estimated cumulative incidence of grade 3 late gastrointestinal toxicity was 14% for 3D-CRT, 5% for IMRT 78, and 2% for IMRT/SIB 82. The difference became significant (log rank p = 0.02). The estimated cumulative incidence of grade 3 late genitourinary toxicity was 9% (3D-CRT), 7% (IMRT 78), and 6% (IMRT/SIB 82) without statistical differences (log rank p = 0.32)


CONCLUSIONS
SIB enables dose escalation up to 82 Gy with a lower rate of gastrointestinal toxicity grade 3 in comparison with 3D-CRT up to 74 Gy.
Dolezel
Martin
M
Oncology Center, Multiscan & Pardubice Regional Hospital, Pardubice, Czech Republic. dolezelm@email.cz
Odrazka
Karel
K
Vaculikova
Miloslava
M
Vanasek
Jaroslav
J
Sefrova
Jana
J
Paluska
Petr
P
Zouhar
Milan
M
Jansa
Jan
J
Macingova
Zuzana
Z
Jarosova
Lida
L
Brodak
Milos
M
Moravek
Petr
P
Hartmann
Igor
I
D000208:Acute Disease; D000368:Aged; D000369:Aged, 80 and over; D003131:Combined Modality Therapy; D003430:Cross-Sectional Studies; D019583:Dose Fractionation, Radiation; D004307:Dose-Response Relationship, Radiation; D005500:Follow-Up Studies; D005767:Gastrointestinal Diseases / Q000453:epidemiology / Q000209:etiology; D041981:Gastrointestinal Tract / Q000528:radiation effects; D006801:Humans; D015994:Incidence; D008297:Male; D052801:Male Urogenital Diseases / Q000453:epidemiology / Q000209:etiology; D008875:Middle Aged; D009367:Neoplasm Staging; D011446:Prospective Studies; D011467:Prostate / Q000528:radiation effects; D011471:Prostatic Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D011832:Radiation Injuries / Q000453:epidemiology / Q000209:etiology*; D020266:Radiotherapy, Conformal / Q000009:adverse effects / Q000379:methods*; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*; D012307:Risk Factors; D012669:Seminal Vesicles / Q000528:radiation effects; D014566:Urogenital System / Q000528:radiation effects