Vulva

GYNVulvaVulvar cancerIMRTVMATSIBBolusInguinal nodesImage fusionMRIPET
Overview

Radiotherapy for vulvar cancer, given definitively, before surgery or after it. The target runs from the pelvic nodes to the skin of the vulva and groins, so the plan has to cover superficial disease with bolus while sparing the anus, rectum, bladder, femoral heads and the skin folds of the groin.

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Schedules

Vulvar cancer is treated definitively or before surgery for locally advanced disease, often with weekly cisplatin, and after surgery when the margins or nodes put the patient at risk. The fields cover the vulva and the inguinofemoral nodes, and often the pelvic nodes.

  • Definitive or pre-operative: 45–50.4 Gy in 25–28 fractions with a sequential boost of 6–16 Gy to gross disease, or an SIB with involved nodes at 2.2–2.3 Gy per fraction (55–57.5 Gy in 25), in the NRG template example.
  • Post-operative: 45–50 Gy in 25 fractions to the operative bed, with a sequential boost of 6–10 Gy where needed.

Higher total doses are used for gross disease in some protocols. Boosts may be planned with IMRT, 3D fields or electrons, depending on where the disease is. Your protocol sets the dose levels and boost approach.

Simulation & Setup

The target runs from the pelvic nodes to the skin of the vulva and groins, so setup has to serve the skin folds, the bolus and the nodes at the same time.

Frog-leg or straight-leg
Supine with the legs immobilized — frog-leg to spare the skin of the upper inner thigh, or straight-leg.

What is it?

Supine in an immobilization device for the legs (such as an alpha cradle or vacuum cushion), either in a frog-leg position or with the legs straight.

Why does it matter?

Frog-leg opens the groins and reduces the skin folds at the top of the inner thigh, sparing that skin. Whichever position is used, it has to be reproduced exactly, because the target reaches the skin.

Wires and markers
Wires on the visible tumor and surgical scars tie the CT to what the physician sees and feels.

What is it?

Wires or other radiopaque markers placed on gross disease and on surgical scars before the scan.

Why does it matter?

Vulvar tumors and scars are easy to see on the patient but hard to see on CT. The wires show the physician's clinical findings on the planning images.

Bolus
Bolus or a virtual bolus where disease reaches the skin, or over post-operative scars.

What is it?

Bolus over the area of concern — large or superficial nodes or skin involvement before surgery; the scars with a margin after surgery — either on the patient at simulation (with a scan without it as well) or added virtually in planning.

Why does it matter?

Without bolus, disease at the skin sits in the build-up region and is under-dosed. Bolus adds skin reaction, so it is used only where the target needs it.

Planning CT
A thin-slice CT or PET/CT from the common iliac bifurcation to mid-thigh, with contrast and a check on rectal distension.

What is it?

A CT or PET/CT with slices of 3 mm or less, from about L3–L4 to mid-thigh. IV contrast helps show the vessels. If the vagina is in the CTV, full- and empty-bladder scans may be used to build an ITV.

Why does it matter?

The groin nodes are drawn around the femoral vessels, so contrast helps. One template recommends repeating the simulation after bowel preparation if the rectum is distended (for example wider than 3.5 cm).

Image fusion — MRI and PET/CT
Pelvic MRI and PET/CT fused with the planning CT — ideally scanned in the treatment position, matched on the tumor.

What is it?

Image fusion aligns an outside scan with the planning CT so the target can be drawn using information the CT doesn't show. For vulvar cancer this is a diagnostic pelvic MRI and/or PET/CT, ideally taken close to the planning scan and, if possible, in the frog-leg position when that is the treatment position.

Why does it matter?

MRI shows the tumor's extent into the vagina, urethra or anus, and PET/CT the involved groin and pelvic nodes. Leg position changes the shape of the perineum and groins, so the registration should focus on the primary tumor rather than the pelvic bones. Deformable registration of the diagnostic MRI is discouraged.

Daily imaging
Daily cone-beam CT, matched to bone with the soft tissue and leg position reviewed.

What is it?

Daily image guidance, usually cone-beam CT matched to the bony anatomy with the soft tissue reviewed.

Why does it matter?

The targets are superficial and in the groins, where leg rotation and skin folds can shift them in ways a bony match doesn't fully show.

Target Delineation

What each volume represents. Expansions, nodal regions and dose levels come only from your protocol.

GTV — Primary and involved nodes

Definition

All gross disease — the vulvar tumor and each involved node — from examination, imaging and biopsy.

Why it matters

The GTV sets where boost doses go, and each involved node may get its own dose level in an SIB.

Contouring resources

Organ contouring guides →

Relevant protocols

CTV — primary — Vulva, or the operative bed

Definition

The vulva and any extension into nearby structures such as the vagina, urethra or anus; after surgery, the whole operative bed.

Why it matters

Protocols extend the CTV along each structure the tumor reaches. Because the primary reaches the skin, the CTV often does too.

Contouring resources

Organ contouring guides →

Relevant protocols

CTV — nodal — Inguinofemoral and pelvic nodes

Definition

The inguinofemoral nodes and, depending on stage, the external and internal iliac and obturator nodes.

Why it matters

Vulvar cancer drains first to the groins. The consensus guideline defines the inguinofemoral region in an appendix, and NRG hosts example cases.

Contouring resources

Organ contouring guides →

Relevant protocols

PTV — Planning target volume

Definition

Each CTV expanded for setup uncertainty. Protocols often create a version cropped a few millimeters inside the skin (for example PTV_4500-03) for optimization.

Why it matters

Cropping stops the optimizer pushing dose into the skin to cover PTV that extends into air — unless the skin is involved, where bolus is used instead.

Contouring resources

Organ contouring guides →

Relevant protocols

Organs at Risk & Dose Constraints

Click an organ for its anatomy, why it matters and contouring resources. Superscripts link to the source behind each value.

Organ45–50.4 Gy / 25–28 fx + boostComposite plan (SIB or sequential boost)
Small Bowel
  • Bowel space D30% ≤40 Gy, D0.03 cc ≤55 Gy1
  • Bowel space V45 Gy ≤190 cc1
Rectum
  • D60% ≤45 Gy, D0.03 cc ≤60 Gy1
Anus / Anal CanalThe max may not be met without losing coverage when the tumor extends posteriorly.
  • D50% ≤40 Gy, D0.03 cc ≤50 Gy1
Bladder
  • D35% ≤45 Gy, D0.03 cc ≤60 Gy1
Femoral HeadsTreating the inguinofemoral nodes brings dose close to the femoral heads and necks.
  • D15% ≤30 Gy, D5% ≤40 Gy1
  • D0.03 cc ≤50 Gy1
Pelvic Bone Marrow
  • Mean ≤30 Gy1
  • V10 Gy ≤85%, V20 Gy ≤70%1
  • Values are the NRG template's per-protocol (ideal) levels, evaluated on the composite plan; its variation-acceptable levels are a few Gy higher (e.g. rectum D60% ≤50 Gy, bowel space V45 Gy ≤300 cc).
  • NRG templates are examples each trial adapts, and the template notes that limits may change where organs overlap the targets.
References (1)
  1. NRG vulva RT template — NRG Oncology Protocol Development Template for Radiation Therapy — Gynecological Cancer: Vulva Cancer. NRG Oncology protocol template Source

Values quoted from NRG vulva RT template, checked by DoseLab on 2026-09-30. Verify against your protocol, institutional policy and physician directive before clinical use.

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Protocols & Literature

Clinical resourceSource Verified
NRG Oncology Protocol Development Template for Radiation Therapy — Gynecological Cancer: Vulva Cancer
Kim H, Beriwal S, Lee YC, Tsai P, Liang X, Padgett K, Portelance L · NRG Oncology Medical Physics Subcommittee / Radiation Oncology Committee · 2024

The NRG Oncology template for the radiation section of a vulvar cancer trial. It covers supine frog-leg or straight-leg setup, wires on gross disease and scars, bolus or virtual bolus, diagnostic MRI and PET/CT fusion (ideally in the treatment position), structure names including the anus and bolus, prescriptions for locally advanced and post-operative treatment with an SIB or a sequential boost, and organ goals evaluated on the composite plan. Its values are examples meant to be edited for each trial.

View Source Details
Contouring atlasUnder Review
Consensus Recommendations for Radiation Therapy Contouring and Treatment of Vulvar Carcinoma
Gaffney DK, King B, Viswanathan AN, et al. · NRG Oncology / RTOG · 2016

NRG/RTOG consensus recommendations for contouring and treating vulvar cancer with IMRT: GTV and CTV definitions for the vulva and the inguinofemoral and pelvic nodes, with an appendix defining the nodal regions. NRG hosts example consensus cases as viewer packages. Citation checked against Europe PMC.

View Source Details
Contouring atlasUnder Review
Female RTOG Normal Pelvis Atlas
Gay HA, Barthold HJ, O'Meara E, et al. · NRG Oncology / RTOG · 2012

NRG Oncology's hosted copy of the RTOG female normal pelvis atlas (from the RTOG pelvic normal tissue consensus): bladder, rectum, sigmoid, bowel, femoral heads and other pelvic organs, as a PowerPoint and an interactive viewer.

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AAPM reportUnder Review

AAPM Task Group 132 report on image registration and fusion in radiotherapy. It reviews rigid and deformable registration, points out that every registration carries an uncertainty that should be understood and communicated, and gives recommendations for commissioning and quality assurance of registration software and for checking individual registrations. Citation checked against Europe PMC.

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Clinical resourceSource Verified

Endorsed eviQ protocol for definitive or neoadjuvant external beam radiotherapy for vulvar cancer, with or without weekly cisplatin. It covers supine frog-leg setup, wiring of scars and clinical mark-up, bolus for superficial disease, MRI and PET/CT for delineation, SIB or sequential-boost dose levels, CTV rules for the vulva, nodes and the subcutaneous mons bridge (referencing the Gaffney 2016 consensus), and the same organ table as its cervix and endometrium protocols. A companion protocol (eviQ 3748) covers post-operative treatment. Its review is due 31 December 2026.

View Source Details

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