Radiotherapy

Locally Advanced Disease (III, IVA, not suitable for brachytherapy boost)

Volumes

GTVp: Primary gross tumour volume, if present
GTVn: Any grossly involved nodes

CTVp: GTVp + 1 cm
CTVn: GTVn + 1 cm

CTVe: Elective nodal CTV. Should include the internal iliac and external iliac nodes. Consider inclusion of inguinal nodes if the tumour is in the proximal or middle vagina. Consider inclusion of mesorectum and presacral nodes if there is involvement of the mesorectum.

PTV45: (CTVp + CTVn + CTVe) + 1 cm
PTV54: (CTVp + CTVn) + 1 cm (if not receiving brachytherapy)
PTV66.6: CTVp + 1 cm (if not receiving brachytherapy)

Dose

Phase 1 - 45 Gy / 25 # (1.8 Gy/#) to PTV45
Phase 2 - 9 Gy / 5# (1.8 Gy/#) to PTV54
Phase 3 - 12.6 Gy in 7# (1.8 Gy/#) to PTV66.6

Technique

3D conformal technique. Phase 1 may be best with a large AP/small PA field with inguinal node boosts, or alternatively opposed AP/PA and electron inguinal node fields. Phase 2 and phase 3 may be best with a 4-field box or other arrangement to reduce toxicity. If the patient has an excellent response to treatment phase 3 may be done with an intracavitary/interstitial brachytherapy boost (similar to doses above).