CÁNCER PRÓSTATA LOCALIZADO SBRT vs Braquiterapia (HDR) HIPOFRACCIONAMIENTO EXTREMO

Qué diferencia ves? SBRT vs HDR

DEFINICIÓN: SBRT VS HDR HIPOFRACCIONAMIENTO EXTREMO

PLATFORM SBRT

PROCEDIMIENTO SBRT

CARACTERÍSTICAS COMUNES SBRT vs HDR Técnica alta precisión Desarrollo tecnológico Software específicos Igual objetivo terapéutico Máxima precisión diana Mínima exposición tejido sano

CARACTERÍSTICAS COMUNES SBRT vs HDR Indicaciones: Riesgo bajo Riesgo intermedio Riesgo alto

FACTORES PARA DECIDIR SBRT vs HDR Eficacia Toxicidad Calidad vida del paciente Costes finales del tratamiento

SBRT vs HDR? What else

Pitfalls of the LQ model in prostate cancer Ultra-large fractions (above 6 Gy) (SBRT and HDR-BT) may not fit the LQ model Overall treatment time (the proliferation factor) a contaminating factor of a/b value Fraction delivery time influencing BED especially of tissues with a low a/b value

a/b (LQ) or a/ b (glq) at doses above 6 Gy?

Clinical Oncol 2013 The mean estimated delivery time for treatment (i.e., one fraction of 7 Gy) was 3 for Rapidarc vs. 39 for Cyberknife Fraction time (hours)

Why the mismatch EBRT vs. HDR-BT? A potential geographical miss with HDR-BT may cause a loss of the biological effective dose (D eff ), which may be determinant for tumors with low a/b values A heterogeneous dose-rate delivery with HDR-BT may also cause a BED loss in tumors with low a/b values

EVIDENCIA CLÍNICA SBRT vs HDR

Series publicadas con RTE + HDR 4.078 ptes 4 15 Gy RB = 90 100% RI = 79 98% RA = 43 93% 79 m 40 105m

IMPORTANCIA CLÍNICA DBE

Ascende-RT NCCN Intermediate- and high-risk PSA 40 ng/ml < T3b Prostate volume 75 cm 3 BPFS Overall Survival 3D-CRT 46 Gy pelvis 32 Gy boost R 3D-CRT + Brachy 46 Gy pelvis 115 Gy I-125 boost

MS: 85m DQE 2Gy : 66Gy Vs 87 Gy 218 PTES

Braquiterapia HDR- Boost 15Gy en 3 fracciones 11-22Gy en 2 fracciones 12-15Gy en 1 fracción

TOXICIDAD SBRT vs HDR

TOXICIDAD SBRT

TOXICIDAD SBRT vs HDR

COSTES SBRT vs HDR

THE FUTURE ON PROSTATE CANCER ONE-SHOT FOR LOCALIZED PROSTATE CANCER

Prostate 17-19 Gy; urethra 15-16 Gy

SBRT (5fx) vs. Radiosurgery (1fx) The Swiss-Italian Transalpine (SIT) prospective multicenter Phase-II Trial Schedule NTD 2Gy αβ=1.5 Gy NTD 2Gy αβ=3 Gy 6.5 Gy x 5 73.1 60.8 7.25 Gy x 5 90.6 74.3 17 Gy x 1 89.9 68 19 Gy x 1 111.3 83.6

ENSAYOS SBRT RANDOMIZADOS EN MARCHA

88 97 100 95 96 88 2.097 p 6-19 Gy 4.5 y 1.6-8 años RB 85-100% RI 88-100% RA 79-93%

HDR MONOTHERAPY

BT-HDR DIL

POWER Partial or Whole gland for ERections Whole gland CTV Hemigland CTV 37

REFLEXIONES FINALES SBRT vs HDR

Prostate Cancer Risk Stratification (NCCN 2017) Very Low risk T1c, GS < 6 (WHO 1), PSA < 10 ng/ml, 3 cores Max 50% cancer/core, PSAD < 0.15 Low risk T1a-T2a, GS < 6 (WHO 1), PSA < 10 ng/ml Intermediate risk T2b-T2c, GS 7(3+4) (WHO 2) or GS 7(4+3) (WHO3), PSA 10 20 ng/ml High risk T3a, GS 8 (WHO 4) or 9-10 (WHO 5), PSA >20 ng/ml) Very High risk (T3b/4) Metastatic (T3b/4) https://www.nccn.org/professionals/physician_gls/pdf/prostate.pdf Those who don t need treatment 10 years PCa Mortality 0.3-5% Challenges Reduce overtreatment Identify subset at risk

https://www.nccn.org/professionals/physician_gls/pdf/prostate.pdf Prostate Cancer Risk Stratification Those treated (NCCN with single 2017) modality Very Low risk T1c, GS < 6 (WHO 1), PSA < 10 ng/ml, 3 cores Max 50% cancer/core, PSAD < 0.15 Low risk T1a-T2a, GS < 6 (WHO 1), PSA < 10 ng/ml Intermediate risk T2b-T2c, GS 7(3+4) (WHO 2) or GS 7(4+3) (WHO3), PSA 10 20 ng/ml High risk T3a, GS 8 (WHO 4) or 9-10 (WHO 5), PSA >20 ng/ml) Very High risk (T3b/4) Metastatic (T3b/4) 10 years PCa Mortality 5-10% Challenges Reduce side-effects of treatment

Prostate Cancer Risk Stratification (NCCN 2017) Very Low risk T1c, GS < 6 (WHO 1), PSA < 10 ng/ml, 3 cores Max 50% cancer/core, PSAD < 0.15 Low risk T1a-T2a, GS < 6 (WHO 1), PSA < 10 ng/ml Intermediate risk T2b-T2c, GS 7(3+4) (WHO 2) or GS 7(4+3) (WHO3), PSA 10 20 ng/ml High risk T3a, GS 8 (WHO 4) or 9-10 (WHO 5), PSA >20 ng/ml) Very High risk (T3b/4) Metastatic (T3b/4) https://www.nccn.org/professionals/physician_gls/pdf/prostate.pdf Those requiring multimodality approach. 10 years PCa Mortality > 30% Challenges Identify subset at risk of progression Implement combinations strategy

Conclusions Extreme hypofractionated RT is trending topic in clinical research for prostate cancer. Available clinical evidence is consistent with a low α/β value for prostate cancer cells (dose/fraction 2.5-4 Gy). Cure rates with HDR-BT +/- EBRT are excellent though high doses are mandatory in order to overcome dose inhomogeneity and geographical misses. Extreme HF (SBRT, dose/fraction 7 Gy) with 5 (or less) fractions should still be a clinical (though very exciting!) research matter.