eContour

60-year-old man with stage IVA (cT2a, cN1, cM0) high risk prostate cancer (grade group 4, iPSA 37.6).

Zoom:
Image:

TECHNIQUE: Patient received neoadjuvant, concurrent, and adjuvant ADT for 2 years. Proximity of small bowel to the right external iliac node required sacrifice of coverage in order to meet small bowel constraints.

DOSE: Patient was treated with whole pelvis radiation to 50.4 Gy in 28 fractions with an SIB to the prostate (and SV) for definitive dose of 70Gy in 28 fractions. Involved nodes were also treated with an SIB to 60 Gy in 28 fractions.

ADT: Patients with node positive disease should receive neoadjuvant, concurrent, and/or adjuvant ADT for 18-36 months (FROGG guidelines). ADT + abiraterone may also be considered per the STAMPEDE trial (James NEJM 2017).

 

 

Case contributed by University of Cincinnati Medical Center

Per NRG Oncology 2021 Updated Consensus

GTV

  • Gross nodal disease seen on imaging. The GTV should be defined on post-neoadjuvant ADT imaging if applicable.

CTV_5040

  • Nodal GTV + 5-7 mm
  • Prostate and seminal vesicles
  • Prophylactic nodal volumes
    • Include common, internal, and external iliac vessels; presacral and obturator nodes.
    • Contours begin at the bifurcation of the aorta into the common iliac arteries.
    • Provide 5-7 mm around iliac arteries and veins.
    • Bone, bowel, bladder, and muscle should be excluded.
    • Prevertebral, presacral, and posterior mesorectal nodes are to be covered to the bottom of S3.
    • Taper off internal illiac contours (internal pudendal artery) at the top of the seminal vesicles.
    • Taper off external iliac contours as the vessels enter the inguinal canal (seen best on coronal images).
    • Obturator nodes end where seminal vesicles join with the prostate.

CTV_6000

  • Nodal GTV + 5 mm
    • Some instiutions will only use a GTV->PTV expansion for involved LN.
    • In this case CTV_6000 is also cropped to not extend outside of CTV_5040. 

CTV_7000

  • Prostate and seminal vesicles

PTV_5040

  • CTV_5040 + CTV_6000 + CTV_7000 + 5 mm

PTV_6000

  • CTV_6000 + 5 mm

PTV_7000

  • CTV_7000 + 5 mm

DOSE:

  • Conventional fractionation = 45-50.4 Gy to elective nodes and 75.6-80 in 38-44 fractions to the prostate and seminal vesicles via sequential boost. Boost gross nodes sequentially to highest achievable dose.
  • Moderate hypofractionation = 3 Gy x 20 fx (44-47 Gy to nodes) and 2.5 Gy x 28 fx (45-50.4 Gy to nodes). Treat elective and gross nodes with simultaneous integrated boost. Boost gross disease to highest achievable dose.

70 Gy in 28 fx OARS: (NRG 2021 Consensus)

  • Rectum
    • V45 Gy ≤ 45%
    • V55 Gy ≤ 25%
    • V65 Gy ≤ 15%
    • V65 Gy < 10 cm3
  • Bladder 
    • V45 Gy ≤ 45%
    • V55 Gy ≤ 25%
    • V65 Gy ≤ 15%
  • Colon
    • V50 Gy ≤ 1%
  • Small bowel
    • V46.5 Gy ≤ 2 cm3
    • Dmax ≤ 52 Gy