The predictive role of ADC values in prostate cancer patients treated with carbon-ion radiotherapy: initial clinical experience at Shanghai Proton and Heavy Ion Center (SPHIC)

• Published in: Journal of cancer research and clinical oncology Vol. 142; no. 6; pp. 1361 - 1367
• Main Authors: Qi, Wei-Xiang, Zhang, Qing, Li, Ping, Zhang, Xiao-Meng, Zhang, Guang-Yuan, Wu, Bin, Lu, Jiade J., Jiang, Guo-Liang, Fu, Shen
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.06.2016; Springer Nature B.V
• Subjects: Aged; Aged, 80 and over; Cancer Research; Carbon; China; Hematology; Humans; Internal Medicine; Ions; Magnetic Resonance Imaging; Male; Medicine; Medicine & Public Health; Middle Aged; Oncology; Original Article – Clinical Oncology; Prostate cancer; Prostatic Neoplasms - radiotherapy; Protons; Radiation therapy; Radiotherapy - methods; Retrospective Studies; Carbon-ion radiotherapy; Prostate-specific antigen; Prostate cancer; Diffusion-weighted MRI
• ISSN: 0171-5216; 1432-1335
• DOI: 10.1007/s00432-016-2142-3

Objective The aim of our study was to investigate the predictive role of apparent diffusion coefficient (ADC) values in evaluating for therapeutic changes from carbon-ion radiotherapy (CIRT) in prostate cancer patients. Materials and methods Thirty-one patients with prostate cancer treated with CIRT were enrolled in this retrospective study. Diffusion-weighted imaging (DWI) at 3-T was performed before and after CIRT. Before and after treatment, ADC values were measured in the tumors and in the benign tissues of the prostate, and serum prostate-specific antigen (PSA) levels were also assessed. We divided the patients into two groups: PSA response (PSA declines ≥50 %) and non-PSA response group (PSA declines <50 %). Results After CIRT treatment, the mean ADC value of the tumors (1.23 × 10 −3 mm 2 /s) was significantly increased as compared with the pretreatment value (1.07 × 10 −3 mm 2 /s) ( p  < 0.001), whereas the ADC values of the benign tissues after treatment did not significantly increase compared with the pretreatment values ( p  = 0.235). The mean PSA level was significantly reduced from 2.027 ng/mL before treatment to 0.822 ng/mL, respectively, after treatment ( p  = 0.0063). The mean of ADC changes in PSA response group before and after CIRT was significantly higher than that in non-PSA response group (∆ADC value: 0.217 vs 0.097 × 10 −3 mm 2 /s, p  = 0.0229), and the rate of patients with PSA response was higher in the high ∆ADC group (∆ADC ≥ 0.10) than in the low ∆ADC group (∆ADC < 0.10) (72.7 and 33.3 %, respectively), but marginally significant ( p  = 0.056). Additionally, the baseline tumor ADC values revealed a negative correlation with changes in PSA levels after treatment (correlation coefficient, ρ  = −0.524; p  = 0.0025). Conclusion Our preliminary results suggest that ADC vales measurement may be a useful imaging biomarker for prediction and early assessment of therapeutic response of prostate cancer to CIRT.