Clinical and technical feasibility of ultra-boost irradiation in Dominant Intraprostatic Lesion by Tomotherapy: preliminary experience and revision of literature.
BACKGROUND
The aim of this paper was to present our experience of dominant intraprostatic lesions (DIL) irradiation up to an EQD2 of 93,2 Gy with helical tomotherapy.


METHODS
Between March 2012 and December 2014, 15 staged II-III patients with intermediate-high risk prostate cancer were enrolled in our protocol of DIL dose escalation by Tomotherapy. All patients were submitted to a multiparametric MRI (including DCE and DWI series), in order to visualize DILs. Considering a mean α/β ratio of 3 for prostate cancer the prescribed doses were: 83.2 Gy in 32 fractions of 2.6 per fraction (EQD2=93.2 Gy) on the DILs, 75.2 Gy in 32 fractions of 2.35 Gy per fraction (EQD2=80.5 Gy) on the prostate gland and 67.2 Gy in 32 fraction of 2.1 (EQD2=68.5 Gy) on the seminal vesicles.


RESULTS
With a mean follow-up of 16 months (range 2-39), no overall severe acute toxicities >G3 were observed; one patient out of 15 (6.6%) had acute gastrointestinal (GI) toxicity equal to G2, while two cases (13.3%) had G2 acute genitourinary (GU) toxicity. No >G2 late toxicity was observed. At last follow-up, for all patients, the biochemical disease free survival was 100%.


CONCLUSIONS
The irradiation of the whole prostate and seminal vesicles up to an EQD2 of 80.5 Gy and of DILs up to 93.2 Gy was clinically feasible and safe, without acute severe toxicity. Although with a short follow-up, late toxicities are currently absent and no patient relapsed.
Radiotherapy Division, FPO‑IRCCS Cancer Center, Candiolo, Turin, Italy - pietro.gabriele@ircc.it.
Elisabetta
E
Garibaldi
Elena
E
Delmastro
Domenico
D
Gabriele
Sara
S
Bresciani
Filippo
F
Russo
Amalia
A
Di Dia
Gaetano
G
Cattari
Gabriella
G
Belli
Pietro
P
Gabriele
D000368:Aged; D017024:Chemotherapy, Adjuvant; D018572:Disease-Free Survival; D005240:Feasibility Studies; D006801:Humans; D007558:Italy; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D009367:Neoplasm Staging; D011471:Prostatic Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D011879:Radiotherapy Dosage; D050397:Radiotherapy, Intensity-Modulated / Q000009:adverse effects; D012669:Seminal Vesicles / Q000528:radiation effects; D013997:Time Factors; D016896:Treatment Outcome