Impact de la chirurgie reconstructrice avec lambeaux et de la chirurgie mini-invasive sur la définition du volume cible anatomoclinique des cancers de la sphère ORL

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Radiothérapie postopératoire en situation de lambeau : série monocentrique avec délinéation de tous les lambeaux pour évaluer les profils de toxicité et de rechute

CERVOXY CLINInternational audiencePurposeFlaps are increasingly used during reconstructive surgery of head and neck cancers to improve functional outcomes. There are no guidelines as to whether the whole flap or its anastomotic border should be included in the primary tumour target volume of postoperative radiotherapy to prevent local relapses. Relapse and toxicity rates can increase substantially if the whole flap received full dose. Our aim was to determine whether flaps were included in the primary tumour target volume and to report the patterns of relapse and toxicity.Materials and methodsConsecutive patients in 2014 through 2016, with or without a flap, receiving postoperative radiotherapy were selected in a retrospective monocentric control study. Flaps were homogenously delineated blind to treating radiation oncologists using a flap-specific atlas. Tumour recurrence, acute and late toxicity were evaluated using univariate and propensity score analyses.ResultsA hundred patients were included; 54 with a flap. Median flap volume included in the tumour volume was 80.9%. Twelve patients experienced local recurrences: six with a flap, among whom two within their flap (3.7%). Patients with flaps had larger median tumour volumes to be irradiated (25 cm3 versus 58 cm3, p < 0.001) and higher acute/late toxicity rates (p < 0.001) even after adjustment on biases (more advanced T stage, oral cavity, active smoking in patients with flaps). Locoregional recurrence and survival rates were similar between patients with/without a flap.ConclusionRecurrences within a flap were rare in this series when including the whole flap body in the 60Gy-clinical target volume but inclusion of the flap in the primary tumour target volume increased toxicity. Multicentric studies are warranted.Objectif de l’étudeLes lambeaux sont de plus en plus utilisés lors de la chirurgie reconstructive des cancers de la tête et du cou pour améliorer les résultats fonctionnels. Il n’existe pas de recommandations publiées sur la définition du volume cible anatomoclinique en situation de lambeau, et notamment sur l’inclusion du lambeau entier ou de son bord anastomotique seulement dans le volume cible anatomoclinique tumoral de la radiothérapie postopératoire pour prévenir les rechutes locales. Les taux de rechute et de toxicité peuvent augmenter si l’ensemble du lambeau a reçu la dose tumoricide. Notre objectif était de déterminer si les lambeaux étaient inclus dans le volume cible anatomoclinique tumoral et de rapporter les modèles de rechute et de toxicité.Matériels et méthodesDes patients consécutifs entre 2014 et 2016 avec ou sans lambeau ayant reçu une radiothérapie postopératoire ont été sélectionnés pour une étude rétrospective de contrôle monocentrique. Les lambeaux ont été délimités de manière homogène, à l’insu des oncologues radiothérapeutes référents, à l’aide d’un atlas spécifique aux lambeaux établi avec les chirurgiens. Les récidives tumorales et la toxicité aiguë et tardive ont été évaluées à l’aide d’analyses unifactorielles et de scores de propension.RésultatsCent patients ont été inclus ; 54 avec un lambeau. Le volume médian du lambeau inclus dans le volume de la tumeur était de 80,9 %. Douze patients ont connu des récidives locales : six avec un lambeau, dont deux dans leur lambeau (3,7 %). Les patients avec des lambeaux avaient des volumes tumoraux médians à irradier plus importants (25 cm3 contre 58 cm3, p < 0,001) et des taux de toxicité aiguë ou tardive plus élevés (p < 0,001), même après ajustement sur les biais (stade T plus grand, cavité buccale, tabagisme actif chez les patients avec des lambeaux). Les taux de récurrence et de survie locorégionaux étaient similaires entre les patients avec ou sans lambeau.ConclusionLes récidives au sein d’un lambeau étaient rares dans cette série dans laquelle le lambeau entier était inclus dans le volume cible anatomoclinique 60 Gy, mais l’inclusion du lambeau dans le volume cible anatomoclinique tumoral augmentait la toxicité. Une étude multicentrique est en cours

Flap delineation guidelines in postoperative head and neck radiation therapy for head and neck cancers.

Reconstructive surgery in head and neck cancers frequently involves the use of autologous flaps to improve functional outcomes. However, the literature suggests that postoperative radiotherapy deteriorates functional outcomes due to flap atrophy and fibrosis. Data on patterns of relapse after postoperative radiotherapy with a flap are lacking, resulting in heterogenous delineation of postoperative clinical target volumes (CTV). Flap delineation is unusual in routine practice and there are no guidelines on how to delineate flaps. Therefore, we aim to propose a guideline for flap delineation in head and neck cancers to assess dose-effects more accurately with respect to flaps. Common flaps were selected. They were delineated by radiation oncologists and head and neck surgeons based on operative reports, on contrast-enhanced planning CTs and checked by a radiologist. Each flap was divided into its vascular pedicle and its soft tissue components (fat, fascia/ muscle, skin, bone). Delineation (body and pedicle) of Facial Artery Musculo-Mucosal, pectoralis, radial forearm, anterolateral thigh, fibula and scapula flaps was performed. Based on information provided in operative reports, i.e. tissue components, size and location, flaps can be identified. The various tissue components of each flap can be individualized to facilitate the delineation. This atlas could serve as a guide for the delineation of flaps and may serve to conduct studies evaluating dose-effects, geometric patterns of failure or functional outcomes after reconstructive surgery. Changes in postoperative CTV definitions might be needed to improve risk/benefit ratio in the future based on surgery-induced changes

International assessment of interobserver reproducibility of flap delineation in head and neck carcinoma.

Background: Several reports have suggested that radiotherapy after reconstructive surgery for head and neck cancer (HNC), could have deleterious effects on the flaps with respect to functional outcomes. To predict and prevent toxicities, flap delineation should be accurate and reproducible. The objective of the present study was to evaluate the interobserver variability of frequent types of flaps used in HNC, based on the recent GORTEC atlas.Materials and methods: Each member of an international working group (WG) consisting of 14 experts delineated the flaps on a CT set from six patients. Each patient had one of the five most commonly used flaps in HNC: a regional pedicled pectoralis major myocutaneous flap, a local pedicled rotational soft tissue facial artery musculo-mucosal (FAMM) (2 patients), a fasciocutaneous radial forearm free flap, a soft tissue anterolateral thigh (ALT) free flap, or a fibular free flap. The WG's contours were compared to a reference contour, validated by a surgeon and a radiologist specializing in HNC. Contours were considered as reproducible if the median Dice Similarity Coefficient (DSC) was &gt; 0.7.Results: The median volumes of the six flaps delineated by the WG were close to the reference contour value, with approximately 50 cc for the pectoral, fibula, and ALT flaps, 20 cc for the radial forearm, and up to 10 cc for the FAMM. The volumetric ratio was thus close to the optimal value of 100% for all flaps. The median DSC obtained by the WG compared to the reference for the pectoralis flap, the FAMM, the radial forearm flap, ALT flap, and the fibular flap were 0.82, 0.40, 0.76, 0.81, and 0.76, respectively.Conclusions: This study showed that the delineation of four main flaps used for HNC was reproducible. The delineation of the FAMM, however, requires close cooperation between radiologist, surgeon and radiation oncologist because of the poor visibility of this flap on CT and its small size