[Guidelines for delineation of pelvic lymph nodes in anal cancer treatment]

Squamous cell anal cancer is a rare malignancy, its incidence increases due to higher exposure of the young adults to risk factors. The current management is based on chemoradiotherapy, which is highly effective and achieves locoregional control but causes important morbidity. Improvement of radiation technique such as intensity modulated radiation therapy has led to reduce acute toxicities, but also requires an accurate delineation of the target volumes in order not to underestimate potential and pathological sites resulting in an increase of the locoregional failures. PET scanner has an important place in the pretreatment work-up for staging and targeting the delineation of the volumes, allowing to select patients with localized disease, avoid geographic miss and appropriately boost nodal disease. The study of recurrences sites has not yet provided a real mapping of the recurrences depending on the treatment volumes. Different radiation oncologist cooperative groups have published guidelines and tools for delineation, in order to provide homogeneity but also customize the management of anal carcinoma.