Case Case Case Case Case br PTV planning target volume
PTV: planning target volume; RTOG: Radiation Therapy Oncology Group.
Local recurrence remains a critical cause of morbidity and mortality even in postoperative pancreatic cancer patients who have received adjuvant chemoradiation [7,10,12,13]. It has been
more than 30 years since the Gastrointestinal Study Group (GITSG) first concluded a survival advantage of adjuvant radiotherapy prospectively in 1985 . However, the significance and value of adjuvant radiotherapy for resected patients is still poorly understood, and the role of postoperative adjuvant radiotherapy
Fig. 3. A new delineation method of the clinical target volume for pancreatic cancer adjuvant radiotherapy: The “new” target volume PTV-90 H edited (red) and the standard
A new delineation method of the clinical target volume for pancreatic cancer adjuvant radiotherapy: Dosimetric constraints and parameters of 13(S)-HODE at risk for the “new” plans and standard plans in five simulated cases.
Organs at risk Constraints “new” plans
RTOG: Radiation Therapy Oncology Group; Dmean: mean dose; Dmax: maximum dose; Vx: volume receiving × Gy.
remains controversial. The critical reason is that the quality of radiotherapy cannot always be ensured. There is still no uniform method for delineating the radiotherapy field, and the dose for the target volume was sometimes insufficient in clinical trials [10,14,15]. Based on the trial of Dholakia et al. and Yu et al. [16,17], this study explored the three-dimensional local recurrence map model of postoperative pancreatic cancer according to clinical recurrence evidence and generated the CTV containing a high-risk local recurrence region for adjuvant radiotherapy by expanding the combined celiac artery and superior mesenteric artery contour.
Dholakia et al. first demonstrated that a majority of local recurrences in patients who had a pancreaticoduodenectomy was contained within a small region surrounding the celiac axis and the superior mesenteric artery and established a three-dimensional
local recurrence map to generate the adjuvant radiotherapy field including high-risk local recurrence areas . But in their data, most patients had undergone radiation, which can reduce the risk of recurrence in irradiation field and then influence the spatial loca-tion of local recurrence. Following the study by Dholakia et al., Yu et al. only included patients with resected pancreatic cancer who did not have a radiotherapy to rule out the impact of irradiation on the local recurrence pattern and further analysed the postoperative local recurrence patterns stratified by the location of the primary tumour. They found that the recurrence pattern was correlated with the location of the primary tumour. Of these, the local recur-rences of both patients with resected pancreatic head cancer and pancreatic body cancer showed a tendency to surround the supe-rior mesenteric artery and celiac axis, but the recurrence location of
Fig. 4. A new delineation method of the clinical target volume for pancreatic cancer adjuvant radiotherapy: Dosimetric comparison of the “new” plan (the first row in each case) and standard plan (the second row in each case) in five simulated cases. In each case, the axial, coronal and sagittal views of the dose colorwashing imaging with the minimum dose of the prescription dose 5040 cGy on the “new” target volume PTV-90 H edited (red) and the standard target volume PTV edited (green) are shown, which are in the same section in both plans. a: case 1; b: case 2; c: case 3; d: case 4; e: case 5.
pancreatic tail cancer seemed at the left rear of the celiac axis and the superior mesenteric artery, and isotonic is not suitable to generate an adjuvant radiotherapy field for pancreatic tail cancer by expanding the celiac artery and the superior mesenteric arteryregions. Lim-ited by the small number of patients with pancreatic body cancer, they only focused on further analysing patients with resected pan-creatic head cancer and created a novel adjuvant field covering the majority of recurrences for this group of patients .