Table 3.
RT treatment techniques and field characteristics
| RT dose∗ | CTV1 | 45 Gy |
|---|---|---|
| CTV2 | 56.25 Gy (50-62.5 Gy) | |
| Volumes | ||
| CTV1 | Pelvic LN recurrence | Per Radiation Therapy Oncology Group (RTOG) contouring guidelines, with exceptions being that the superior margin was routinely at the level of the aortic bifurcation30 and presacral regions below the S2-3 level were included as clinically indicated |
| PA LN recurrence | Included pelvic LN volumes (per CTV1) plus 1.5-2 cm above the most superior CholPET-avid site of recurrence | |
| CTV2 | Gross CholPET-avid disease with an additional 5-10 mm anatomically constrained expansion (cropped out of bowel, bladder, and bone). | |
| Image guidance | Daily cone beam CT and/or kilovoltage orthogonal x-rays | |
| RT technique | Volumetrically modulated arc therapy | |
| Small bowel DVH constraints and achieved statistics† | Small bowel (bowel bag) | Max <52 Gy (50.8, 48.7, 52.4) |
| V50 Gy < 2 cm3 (0.1, 0, 1.0) | ||
| V45 Gy < 150 cm3 (27.9, 10.3, 44.3) | ||
| V30 Gy < 300 cm3 (213.4, 112.6, 272.2) | ||
| Superior RT field border‡ | L5/S1 | 12 (11.2%) |
| L4/L5 | 24 (22.4%) | |
| L3/L4 | 21 (19.6%) | |
| L2/L3 | 18 (16.8%) | |
| L1/L2 | 23 (21.5%) | |
| T12/L1 | 7 (6.5%) | |
| T11/T12 | 2 (1.9%) | |
Abbreviations: CholPET = 11C-choline-positron emission tomography; CT = computed tomography; CTV = clinical target volume; DVH = dose-volume histogram; LN = lymph node; PA = paraortic; RT = radiation therapy.
Values are reported as *median (range), †median (interquartile range), or as ‡number (%).