18. Primary vaginal cancer and vaginal recurrences - The GEC-ESTRO Handbook of Brachytherapy

Primary vaginal cancer and vaginal recurrences

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THE GEC ESTRO HANDBOOK OF BRACHYTHERAPY | Part II Clinical Practice Version 1 - 01/09/2023

Figure 3. Transverse MRI and corresponding transverse TRUS imaging before, during and after applicator implantation in a patient with primary vaginal cancer with urinary bladder invasion. Upper row: plain images, lower row: same images with contours and marks indicating the inserted needles. From left to right: Panel 1: pre-brachytherapy MRI with cylinder in situ; Panel 2-6: TRUS during implantation showing stepwise needle insertion; Panel 7: Treatment planning MRI with final implant; yellow contour: urinary bladder; red contour: CTV-T HR , white circles indicate interstitial needles.

brachytherapy. Finally, a vaginal mould with the impression of the tumour could be useful for documentation and even used for treatment of superficial tumours [13]. Nowadays the standard imaging modality for evaluation of the primary vaginal tumour, and for contouring and planning at the time of brachytherapy, is an abdominal-pelvic MRI including the whole vagino-vulvar region. Trans-vaginal and trans-rectal ultrasound is helpful to precisely evaluate the morphology and topography of the tumour in the vagina and guide the implantation (Figure 3). In addition, for assessment of lymph node and distant metastases CT or PET CT is advised. In selected cases, cystoscopy or proctoscopy is performed, in particular when involvement of bladder or rectum is suspected [7, 12]. Careful pre-brachy treatment planning is of great value to achieve the best possible implant and therefore the best treatment plan at time of brachytherapy (BT). A pre-brachytherapy MRI in the fourth or fifth week of external beam radiotherapy (EBRT) with an intracavitary applicator (e.g., cylinder) or vaginal gel could be helpful (Figure 4). This pre-BT MRI in combination with the diagnostic MRI allows for contouring of the target, and helps to decide which applicator should be used and where, and how many, interstitial needles should be inserted. At the time of implantation or in the week before, gynaecological examination and vaginal ultrasound further help to fine-tune the implantation. Locally advanced primary vaginal cancer (T2-T4) and early stage disease (T1) not amenable for non-mutilating surgery should be treated with definitive external beam radiotherapy (EBRT) and platinum-based concurrent chemotherapy [14], followed by a brachytherapy (BT) boost to the primary tumour [7, 15]. Patients unfit for concurrent chemotherapy may be considered for regional hyperthermia [16]. Selected primary or recurrent vaginal tumours up to 2cm diameter and 7mm thickness without any evidence of nodal disease may be considered for treatment with brachytherapy alone [15]. Locally advanced vaginal recurrences from cervical or endometrial cancer without a previous history of radiotherapy should be treated the same as primary vaginal tumours, with a combination of EBRT 6. INDICATIONS AND CONTRA-INDICATIONS

Figure 4. Examples of (a, b, c) MRI at diagnosis with vaginal gel in situ and, (d, e, f) pre brachytherapy MRI in the fourth week of EBRT with a cylinder dummy in situ, in transversal, sagittal and coronal view, respectively (from left to right). The green line indicates the location in the corresponding orthogonal views. The red star indicates the vaginal gel (white); the tau indicates the vaginal cylinder.

(endometrium, ovarian cancer) and other malignancies. When a vaginal tumour extends to less than 1 cm of the ostium of the cervix or to the vulva, it should be classified as a cervical or vulvar cancer, respectively [11]. The local extent of a vaginal tumour is in general easily evaluated by gynaecological examination, preferably by two examiners, which should not be abandoned as it gives valuable and additional information to imaging, especially in the case of superficial tumours. Recently, the Groupe Européen de Curiethérapie – European Society for Radiotherapy and Oncology (GEC-ESTRO) GYN (gynaecology) taskforce for vaginal tumours adapted the clinical drawings used for cervical cancer for a precise and reproducible description of the local extent of the vaginal tumour [12] (Figure 2a and b). This clinical drawing diagram allows for a full three-dimensional description which implies a clockwise definition of the tumour spread at upper, middle and lower third, the length of the tumour along the vaginal axis, the thickness perpendicular to the vaginal axis, and the width of the tumour including any paravaginal extension. In addition, the tumour-free distance from the vaginal top at the cervix to the proximal part of the tumour, and from the distal part towards the introitus should be documented. The implantation of markers at the borders of the tumour at time of diagnosis is helpful for target volume definition at time of