Correlation between acute and late toxicity in 973 prostate cancer patients treated with three-dimensional conformal external beam radiotherapy.
OBJECTIVE
To analyze the correlation between acute and late injury in 973 prostate cancer patients treated with radiotherapy and to evaluate the effect of patient-, tumor-, and treatment-related variables on toxicity.


METHODS
Of the 973 patients, 542 and 431 received definitive or postprostatectomy radiotherapy, respectively. Three-dimensional conformal radiotherapy included a six-field technique and two-dynamic arc therapy. Toxicity was classified according to the Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer criteria. The correlation between acute and late toxicity (incidence and severity) was assessed.


RESULTS
Multivariate analysis showed that age </=65 years (p = .06) and use of the three-dimensional, six-field technique (p <.0001) correlated significantly with greater acute rectal toxicity. The three-dimensional, six-field technique (p = .0002), dose >70 Gy (p = .014), and radiotherapy duration (p = .05) correlated with greater acute urinary toxicity. Acute rectal toxicity (p <.0001) was the only factor that correlated with late rectal injury on multivariate analysis. Late urinary toxicity correlated with acute urinary events (p <.0001) and was inversely related to the use of salvage radiotherapy (p = .018). A highly significant correlation was found between the incidence of acute and late events for both rectal (p <.001) and urinary (p <.001) reactions. The severity of acute toxicity (Grade 2 or greater) was predictive for the severity of late toxicity for both rectal and urinary events (p <.001).


CONCLUSIONS
The results of our study have shown that the risk of acute reactions depends on both patient-related (age) and treatment-related (dose, technique) factors. Acute toxicity was an independent significant predictor of late toxicity. These findings might help to predict and prevent late radiotherapy-induced complications.
Department of Radiotherapy, European Institute of Oncology, Milan, Italy; University of Milan, Milan, Italy. barbara.jereczek@ieo.it
Barbara A
BA
Jereczek-Fossa
Dario
D
Zerini
Cristiana
C
Fodor
Luigi
L
Santoro
Flavia
F
Serafini
Raffaella
R
Cambria
Andrea
A
Vavassori
Federica
F
Cattani
Cristina
C
Garibaldi
Federica
F
Gherardi
Annamaria
A
Ferrari
Bernardo
B
Rocco
Epifanio
E
Scardino
Ottavio
O
de Cobelli
Roberto
R
Orecchia
D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D004307:Dose-Response Relationship, Radiation; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011468:Prostatectomy; D011471:Prostatic Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D011832:Radiation Injuries / Q000473:pathology*; D011879:Radiotherapy Dosage; D018714:Radiotherapy, Adjuvant; D020266:Radiotherapy, Conformal / Q000009:adverse effects* / Q000379:methods; D012007:Rectum / Q000528:radiation effects*; D016879:Salvage Therapy; D012720:Severity of Illness Index; D001743:Urinary Bladder / Q000528:radiation effects*