Purpose
Desmoplastic small round cell tumor (DSCRT) is an uncommon pediatric tumor with a poor prognosis. Aggressive multimodality therapy is the current treatment approach, however treatment toxicity is of concern. We report our results with whole abdominopelvic intensity-modulated radiation therapy (WAP-IMRT) as a component of multimodality therapy for DSCRT at a single institution.
Materials/Methods
Medical records of all patients with DSCRT who received WAP-IMRT as part of definitive treatment at MD Anderson (2006-2010) were identified and reviewed.
Results
Eight patients with DSRCT received WAP-IMRT with a median follow-up of 15.2 months. All patients received multiple courses of chemotherapy followed by surgical debulking of intra-abdominal disease; seven also had intraoperative hyperthermic cisplatin. WAP-IMRT was delivered to a total dose of 30 Gy post-operatively; four patients received a simultaneous boost (6-10 Gy) to sites of gross residual disease. Seven patients received concurrent chemotherapy during WAP-IMRT. No RTOG grade 4 nausea, vomiting, or diarrhea occurred during RT. Red cell transfusions were given to two patients to maintain hemoglobin levels of greater than 10 g/dL. Grade 4 cytopenia requiring growth factor support occurred in only one patient; no other significant cytopenias were noted. WAP-IMRT resulted in 25% lower radiation doses to the lumbosacral vertebral bodies and pelvic bones than conventional RT plans. The median time to local or distant failure after WAP-IMRT was 8.73 months in seven patients. One patient who had completed RT 20 months before the last follow-up remains alive without evidence of disease. Five patients (63%) experienced treatment failure in the abdomen. Distant failure occurred in three patients (37.5%).
Conclusions
WAP-IMRT with concurrent radiosensitizing chemotherapy was well tolerated after aggressive surgery for DSCRT. Enhanced bone sparing with IMRT probably accounts for the low hematologic toxicity (vs. conventional WAP RT). This modality should be considered as an additional local-regional control option for DSRCT.
Reirradiation with chemotherapy may be feasible to improve symptoms and delay progression with minimal toxicity. Patients who are most likely to benefit may be those with prolonged response to initial therapy and a long interval since initial radiation.
Summary
This study presents a map of PET-positive paraaortic nodes (PAN) in cervical cancer. Available information about the location of PAN metastases in cervical cancer is not adequately detailed to guide treatment planning for highly conformal radiation therapy. Our population based atlas outlines the spatial distribution of these lymph nodes to facilitate target delineation and treatment planning. Suggested clinical target volume contours are included, which provide coverage of PAN nodes for the treatment of cervical cancer.
Purpose
Conformal treatment of paraaortic lymph nodes (PAN) in cervical cancer allows dose escalation and reduces normal tissue toxicity. Currently, data documenting the precise location of involved PAN are lacking. We define the spatial distribution of this high-risk nodal volume by analyzing FDG-avid lymph nodes (LNs) on PET/CT scans in patients with cervical cancer.
Materials/Methods
We identified 72 PANs on pretreatment PET/CT of 30 patients with newly-diagnosed stage IB-IVA cervical cancer treated with definitive chemoradiation. LNs were classified as left-lateral paraaortic (LPA), aortocaval (AC), right paracaval (RPC). Distances from the LN center to the closest vessel and adjacent vertebral body were calculated. Using deformable image registration, nodes were mapped to a template CT to provide a visual impression of nodal frequencies and anatomic distribution.
Results
We identified 72 PET positive paraaortic lymph nodes (37 LPA, 32 AC, 3 RPC). All RPC lymph nodes were in the inferior 1/3 of the paraaortic region. The mean distance from aorta for all lymph nodes was 8.3 mm (range 3 to 17 mm), and from the inferior vena cava was 5.6 mm (range 2 to 10 mm). Of the 72 lymph nodes, 60% were in the inferior third, 36% were in the middle third and 4% were in the upper third of the paraaortic region. 29/30 patients also had FDG-avid pelvic lymph nodes.
Conclusions
96% of PET positive nodes were adjacent to the aorta; PET positive nodes to the right of the IVC were rare and were all located distally, within 3 cm of the aortic bifurcation. Our findings suggest that circumferential margins around the vessels do not accurately define the nodal region at risk. Instead, the anatomical extent of the nodal basin should be contoured on each axial image in order to provide optimal coverage of the paraaortic nodal compartment.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.