Post-Operative Radiotherapy for Soft Tissue Sarcoma of the Anterior Compartment of the Thigh: Should the Sartorius Muscle be Included?

摘要

Purpose:The clinical target volume (CTV) of post-operative radiotherapy for soft tissue sarcoma of the limbsconventionally includes the whole of the transverse cross-section of the affected anatomical compartment. In the anteriorthigh sartorius appears to lie within its own fascial compartment and can be safely excluded. We investigated the potentialimpact of omitting sartorius from the anterior muscle compartment on patients with soft tissue sarcoma of the thigh.Patients and methods:We used the planning CT data from six patients who had previously received post-operativeradiotherapy for soft tissue sarcoma of the thigh. The anterior compartments were outlined twice, initially including andthen excluding the sartorius muscle. The volumes of the anterior compartment (i.e., the CTVs), both with and withoutsartorius, and the corresponding planning target volumes (PTVs) were calculated. Treatment plans were prepared for eachPTV. For both volumes the unirradiated normal tissue corridor was outlined on each CT slice. The volume andcircumference of the unirradiated corridor were then calculated.Results:For all six patients there was an important improvement in normal tissue sparing by excluding sartorius. Themean reduction in volume of the anterior compartment when sartorius was excluded was 10% (95% Confidence Interval8–12%), whilst the mean decrease in PTV was 11% (95% CI 7–14%). There was a substantial increase in the volume of theunirradiated normal tissue corridor, with a mean value of 77% (95% CI 41–114%) when sartorius was excluded.In addition, the percentage increase in the size of the unirradiated normal tissue corridor, expressed as a percentage ofthe whole leg circumference, was 10% (95% CI 8–13%). When sartorius was included in the anterior compartment,the circumference of the unirradiated corridor was less than one-third of the whole leg circumference in four of the sixpatients. When sartorius was excluded, the circumference of the unirradiated corridor was greater than one-third of the legcircumference over the entire length of the target volume in all patients.Discussion:It is essential to know the anatomy of the sartorius muscle to be able to exclude it from the anteriorcompartment. The increase in the size of the normal tissue corridor when sartorius is excluded should deliver clinicaladvantage by decreasing the normal tissue adverse effects.