There have been conflicting reports regarding the incidence of duodenal toxicity in patients receiving intensity modulated radiation therapy (IMRT) with an extended field covering the para-aortic (PA) lymph nodes for gynecologic cancers. We reviewed our experiences and rates of duodenal toxicity in patients treated with extended field IMRT.

Patients with either cervical or endometrial cancer who were treated with IMRT to the PA nodes for involved lymph nodes or for prophylactic intent between 2005 and 2013 were included. For prophylactic intent, the radiation dose to the PA nodes was 45 Gy in 25 fractions. For involved lymph nodes, a boost was delivered to the gross disease with a 0.7-cm expansion, with editing for critical structures. The entire duodenum was retrospectively contoured on all patients from the gastric outlet to the jejunal transition.

We identified 76 eligible patients with endometrial and cervical cancer. The PA region was treated prophylactically in 46.1% (n = 35) and for involved PA lymph nodes in 53.9% (n = 41). The duodenum was contoured on all patients with a median volume of 83.2 cm(3) (range, 21.2-174.9 cm(3)). The mean volume of duodenum receiving 55 Gy (V55) for those treated prophylactically and for involved PA nodes was 0 cm(3) and 0.8 cm(3) (range, 0-10.6 cm(3)), respectively (P = .014). Specifically, no patient had a V55 >15 cm(3). The mean V40 was 28.3 cm(3) (range, 0-77.3 cm(3)) and 41.4 (range, 0-90.0 cm(3)), respectively (P = .016). The mean dose delivered to 2 cm(3) of the duodenum was 34.9 Gy (range, 0-52.3 Gy) and 50.1 Gy (range, 31.3 - 58.3 Gy), respectively. Grade 3 acute gastrointestinal toxicity was recorded in 3.9% (n = 3) of patients.

In our experience, the treatment of PA lymph nodes using an IMRT technique is associated with a low duodenal toxicity profile and there has been no high-grade late duodenal toxicity.