Ces Urol 2013, 17(3):175-182 | DOI: 10.48095/cccu2013021

Dose escalation to the intraprostatic lesion - the results of acute and early late toxicity

Martin Doležel^1,2,3, Karel Odrážka^1,2, Jaroslav Vaňásek¹, Milan Mrklovský¹, Petr Hoffmann⁴, Karel Lucký⁵, Igor Hartmann^3,6

¹ KOC Pardubická krajská nemocnice a.s. a Multiscan s.r.o., Pardubice

² 1. lékařská fakulta, Univerzita Karlova v Praze

³ Lékařská fakulta UP, Olomouc

⁴ Radiologická klinika FN, Hradec Králové

⁵ Urologické oddělení, Pardubická krajská nemocnice a.s.

⁶ Urologická klinika FN, Olomouc

Aim:
To evaluate the feasibility and toxicity of dose escalation to the intraprostatic lesion to 84.84 Gy in 40 fractions using simultaneous integrated boost (SIB).

Methods:
Between September 2009 and September 2012, we treated 41 patients with intensity-modulated radiotherapy (IMRT) for prostate cancer using SIB. Intraprostatic lesion was defined by MRI or MRI plus spectroscopy transrectal ultrasound and physical examination. The prescribed doses were 84.84 Gy 80 Gy and 76 Gy in 40 fractions to the intraprostatic lesion, high risk volume and prostate with seminal vesicles (SIB 84.84). Late toxicity was prospectively scored according to the RTOG/FC-LENT scale. The results were compared to 138 patients treated with IMRT covering the prostate and base of seminal vesicles to 78 Gy (IMRT 78).

Results:
Acute genitourinary toxicity grade > 2 was observed in 9.6% (SIB 84.84) and 33.3% (IMRT 78), with a significant difference (p < 0.01). Acute gastrointestinal toxicity grade > 2 occurred in 16% of patients treated with IMRT and in 2.5% receiving SIB with a significant difference (p = 0.01). With a median follow up of 24.1 months, the cumulative incidence of grade > 2 late genitourinary toxicity was 10.2% for IMRT 78 and 5% for SIB 84.84. This difference did not reach statistical difference (p = 0.24). The late gastrointestinal toxicity grade > 2 developed in 13% of cases in the IMRT 78 group and 7.4% in SIB 84.84 group which was not statistically significant (log rankp = 0.24).

Conclusion:
Simultaneous integrated boost enables dose escalation up to 84.84 Gy in 40 fractions to the intraprostatic lesion with a low rate of gastrointestinal and genitourinary toxicity.

Keywords: prostate cancer, radiotherapy, simultaneous integrated boost

Received: April 22, 2013; Accepted: April 25, 2013; Published: June 1, 2013