Genitourinary Cancer

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SU_33_2333 - Functional,radiological imaging and biochemical ( PET PSMA,MRI,ADC,PSA) response and its correlation in low and intermediate risk prostate cancer treated with SBRT by robotic radiosurgery alone.

Sunday, October 21
1:15 PM - 2:45 PM
Location: Innovation Hub, Exhibit Hall 3

Functional,radiological imaging and biochemical ( PET PSMA,MRI,ADC,PSA) response and its correlation in low and intermediate risk prostate cancer treated with SBRT by robotic radiosurgery alone.
P. S. Sridhar1, N. Madhusudhan1, K. Roopesh1, M. Praveen kumar1, G. H. Abilash1, S. Kundavai1, P. Anuradha1, M. Hamid2, M. Wambani3, S. S1, A. Jerrin1, K. Kallur1, S. Shiva kumar1, K. Bijina1, P. Anchineyan Sr1, M. Govindrajan1, G. Kilara1, R. S. Bilimagga1, and B. ajai Kumar1; 1Health Care Global Enterprises Ltd, Bangalore, India, 2HCG RMC, Daresalam, Tanzania, United Republic of, 3HCGCCK, Nairobi, Kenya

Purpose/Objective(s): Robotic radiosurgery SBRT for Prostate cancer is popularizing due to good local control & low toxicity in low and intermediate risk patients. While PSA & MRI ADC values are established markers for diagnosis and response assessment, PSMA PET CT functional imaging is emerging as a promising diagnostic tool. PSA are susceptible to infections and poses challenges for response assessment and ADC values are usually change slowly and might not detect response in time. This study is an attempt to evaluate the non-inferiority of PSMA PET SUV values as a surrogate marker along with PSA and ADC values for response to robotic radiosurgery SBRT.

Materials/Methods: 36 patients of biopsy-confirmed early prostate cancer were retrospectively analysed. Patients underwent baseline and followup PSMA PET CT scan,MRI,ADC value,PSA. Patients underwent PSMA PET CT,MRI based SBRT by robotic radiosurgery planning to the GTV prostate to dose of 37.50Gy in 5 fractions alternate day treatment.All 36 patients were analysed for PSA value,PSMA PET CT SUV of tumor,MRI prostate volume,ADC values. Wilcoxon signed rank tests were used.

Results: Among 36 patients Mean age was 64.2 years range 51-75 years. 11 patients were low risk,25 were intermediate risk.Mean PSA at baseline,3 month,6 month,12 month,and 24 month was 13.5±7.5 ng/ml, 4.56±5.71 ng/ml, 2.73±1.77 ng/ml, 1.42±1.25 ng/ml and .66±.39 ng/ml respectively. Mean PSMA PET CT SUV at baseline, 6 months, 12 months and 24 months were 10.45±12.54, 3.76±1.74, 3.92±0.91, and 2.63±1 respectively. Mean ADC values at baseline, 6 months, 12 months and 24 months were 0.7913±0.2108, 1.19±0.18, 1.32±0.23 and 4.28±1.06 respectively. Mean MRI volume at baseline, 6 months, 12 months and 24 months were 4.4±1.2cc, 4.56±0.75cc, 4.42±4.77cc and 4.28±1cc respectively. Base line values were compared with their respective post treatment values using the Wilcoxon Signed Rank Test with appropriate Bonferroni corrections.
PSA PSA3MTH- PSApres PSA6mth- PSApres PSA12mth- PSApres PSA24mth- PSApres
z -2.201b -3.724b -3.408b -2.803b
Asymp. Sig. (2-tailed) .028 .000 .001 .005
PSMA PETCT SUV SUV at 6months - SUV at Present SUV at 12Months - SUV at Present SUV at 24Months - SUV at Present
z -2.936b -2.310b -1.069b
Asymp. Sig. (2-tailed) .003 .021 .285
ADC 6MMriAdc - DiagMriAdc
12MMriAdc - DiagMriAdc
12MMriAdc - 6MMriAdc
Z -2.670b -1.826b -1.342b
Asymp. Sig. (2-tailed) .008 .068 .180
MRI 6mmmri - Mrisize 12mri - Mrisize 24mri - Mrisize
z -2.532b -2.070b -1.841b
Asymp. Sig. (2-tailed)
.011 .038 .066
a. Wilcoxon Signed Ranks Test
b. Based on positive ranks.

Conclusion: In our study there was a significant reduction in PSA, PSMA PETCT SUV, MRI Tumor Size and ADC values in 6 months of robotic radiosurgery SBRT. Hence PSMA PET CT SUV values could be used as functional surrogate marker along with PSA biochemical marker earlier than MRI and ADC values. A prospective trial with PSMA done at 3 months is underway and a study with larger numbers may be required to generate stronger towards this conclusion.

Author Disclosure: P. Sridhar: None. N. Madhusudhan: None. M. Praveen kumar: None. G.H. Abilash: None. S. Kundavai: None. M. Hamid: None. S. S: None. A. Jerrin: None. P. Anchineyan: None. R.S. Bilimagga: Honoraria; Health Care Global Enterprises Limited, INDIA. Stock; Health Care Global Enterprises INDIA. Past President; AROI.

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SU_33_2333 - Functional,radiological imaging and biochemical ( PET PSMA,MRI,ADC,PSA) response and its correlation in low and intermediate risk prostate cancer treated with SBRT by robotic radiosurgery alone.



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