Cervical External Beam Radiation


  • Goals include reducing the endocervical and exocervical components of the tumors to optimize ICRT and to sterilize the nodes.
  • Doses: 40-45Gy EBRT but total including ICRT is typically 50-55Gy. Need to treat the grossly affected parametria, pelvic sidewall, and nodes to 60-65Gy.

Technique: Use 15-18MV with 4-field technique.

  • superior: L4-L5
  • Inferior: mid-pubic bone or 3-4 cm below the vaginal extent of disease;
  • lateral: 1.5cm beyond the pelvic rim.
  • For the AP field, the nodal chains extend on a line between 2cm lateral from mid-L4 and 6cm lateral from midpelvis.
  • Need to include entire sacrum to cover disease in uterosacral and cardinal ligaments and superior rectal and sacral nodes
  • superior border: tip of the pubic symphysis
  • inferior border: Use CT planning and give tumor 3cm. Splitting the sacrum at S3 can under-dose tumor. If there is a significant risk for involvement of the presacral nodes or uterosacral ligaments (attach at S3) then include the entire thickness of the sacrum.
  • If the distal vagina is involved then include the inguinal nodes in treatment.
  • For treatment of paraaortic nodes, use 18MV and the chimney portion of the lateral field must be at least 5cm anterior to posterior.
  • May treat with bladder full and prone to possibly Ø dose to small bowel.


The involved lateral parametrium and/or involved pelvic nodes will be boosted with 9.6 Gy given 1.2 Gy per fraction per day x 8 fractions during weeks 4-5 concomitantly with midline shield as shown in the example schema. Dose to poin P (6 cm lateral to the midline of pelvis) from external beam only will be > 54.6 Gy.

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