Tumor Size on Abdominal MRI Versus Pathologic Specimen in Resected Pancreatic Adenocarcinoma: Implications for Radiation Treatment Planning

Hall, William A.; Mikell, J.L.; Mittal, Pardeep K.; Colbert, Lauren E.; Prabhu, Roshan S.; Kooby, David A.; Nickleach, Dana; Hanley, Krisztina; Sarmiento, Juan M.; Ali, Arif; Landry, Jerome C.

doi:10.1016/j.ijrobp.2012.11.019

Cited by 34 publications

(35 citation statements)

References 19 publications

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“…Multi-modality imaging including FDG-PET and multi-parametric MRI can be used to guide the clinician but the potential effect on outcomes remains uncertain [25]. In addition pathology correlation studies suggest that tumour size is underestimated by some imaging modalities [27], [28]. The value of direct radiologist support in radiotherapy planning is increasingly understood [29] however this does not obviate the requirement for the modern radiation oncologist to be skilled in multi-modality image interpretation and have highly detailed anatomical knowledge in order to safely deliver complex treatments such as described here.…”

Section: Discussionmentioning

confidence: 99%

Conformity analysis to demonstrate reproducibility of target volumes for Margin-Intense Stereotactic Radiotherapy for borderline-resectable pancreatic cancer

Holyoake

Robinson

Grose

et al. 2016

Radiotherapy and Oncology

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Background and purposeMargin-directed neoadjuvant radiotherapy for borderline-resectable pancreatic cancer (BRPC) aims to facilitate clear surgical margins. A systematic method was developed for definition of a boost target volume prior to a formal phase-I study.Material and methodsReference structures were defined by two oncologists and one radiologist, target structures were submitted by eight oncologist investigators and compared using conformity indices. Resultant risk of duodenal bleed (NTCP) was modelled.ResultsFor GTV, reference volume was 2.1 cm3 and investigator mean was 6.03 cm3 (95% CI 3.92–8.13 cm3), for boost volume 1.1 cm3 and 1.25 cm3 (1.02–1.48 cm3). Mean Dice conformity coefficient for GTV was 0.47 (0.38–0.56), and for boost volume was significantly higher at 0.61 (0.52–0.70, p = 0.01). Discordance index (DI) for GTV was 0.65 (0.56–0.75) and for boost volume was significantly lower at 0.39 (0.28–0.49, p = 0.001). NTCP using reference contours was 2.95%, with mean for investigator contour plans 3.93% (3.63–4.22%). Correlations were seen between NTCP and GTV volume (p = 0.02) and NTCP and DI (correlation coefficient 0.83 (0.29–0.97), p = 0.01).ConclusionsBetter conformity with reference was shown for boost volume compared with GTV. Investigator GTV volumes were larger than reference, had higher DI scores and modelled toxicity risk. A consistent method of target structure definition for margin-directed pancreatic radiotherapy is demonstrated.

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Section: Discussionmentioning

confidence: 99%

Conformity analysis to demonstrate reproducibility of target volumes for Margin-Intense Stereotactic Radiotherapy for borderline-resectable pancreatic cancer

Holyoake

Robinson

Grose

et al. 2016

Radiotherapy and Oncology

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“…Additionally, an often overlooked and understudied area of RT delivery in unresectable PAC is the modality of GTV delineation. Recently, retrospective data have emerged and called into question the volumes delineated on abdominal CT and MRI (17,18). When local tumors are treated alone with increasingly small margins, the process of a pancreatic tumor GTV delineation must be carefully studied before a minimal margin is used expanding GTV-PTV.…”

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confidence: 99%

The Influence of Radiation Therapy Dose Escalation on Overall Survival in Unresectable Pancreatic Adenocarcinoma

Hall

Colbert

Nickleach

et al. 2013

International Journal of Radiation Oncology*Biology*Physics

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.Purpose: Radiation therapy (RT) dose escalation in unresectable pancreatic adenocarcinoma (PAC) remains investigational. We examined the association between total RT dose and overall survival (OS) in patients with unresectable PAC.Methods and materials: National cancer data base (NCDB) data were obtained for patients who underwent definitive chemotherapy and RT (chemo-RT) for unresectable PAC. Univariate (UV) and multivariate (MV) survival analysis were performed along with Kaplan-Meier (KM) estimates for incremental RT dose levels.Results: A total of 977 analyzable patients met inclusion criteria. Median tumor size was 4.0 cm (0.3-40 cm) and median RT dose was 45 Gy. Median OS was 10 months (95% CI, 9-10 months). On MV analysis RT dose <30 Gy [HR, 2.38 (95% CI, 1.85-3.07); P<0.001] and RT dose ≥30 to <40 Gy [HR, 1.41 (95% CI, 1.04-1.91); P=0.026] were associated with lower OS when compared with dose ≥55 Gy. Patients receiving RT doses from 40 to <45, 45 to <50, 50 to <55, and ≥55 Gy did not differ in OS.Conclusions: Lack of benefit to OS with conventionally delivered RT above 40 Gy is shown. Optimal RT dose escalation methods in unresectable PAC remain an important subject for investigation in prospective clinical trials.Keywords: Radiation dose escalation pancreatic cancer; radiation dose escalation in pancreatic adenocarcinoma (PAC); unresectable pancreatic cancer; PAC and radiation therapy (RT); RT dose in unresectable pancreatic cancer; PAC and intensity modulated radiation therapy (IMRT); dose response pancreatic cancer Submitted Jan 18, 2014. Accepted for publication Feb 19, 2014Feb 19, . doi: 10.3978/j.issn.2078Feb 19, -6891.2014 View this article at: http://www.thejgo.org/article/view/2321/2900 78 Hall et al. Radiation therapy dose escalation and unresectable PAC© Pioneer Bioscience Publishing Company. All rights reserved.J Gastrointest Oncol 2014;5(2):77-85 www.thejgo.org conducted examining RT dose escalation (5)(6)(7)(8)(9)(10)(11)(12)(13)(14). These trials have resulted in conflicting conclusions regarding the benefits of increasing RT dose. The goal of this series was to examine the effect of RT dose escalation in nonmetastatic, unresectable PAC through an analysis of the national cancer data base (NCDB). Patients and methodsOur patient population was obtained from the Pancreatic Participant Use Data File (PUF) from the NCDB, which is one of the world's largest clinical cancer registries (15). The NCDB is supported by the American College of Surgeons and the American Cancer Society (15) and includes more than 1,440 hospitals in the United States. Data available include patient demographics, pathologic characteristics, detailed staging, RT dose information, chemotherapy data, and overall survival (OS) data.Emory University was granted alpha-test user site status for the Pancreatic PUF, which includes all incident cases of PAC reported to the NCDB for the 5-year period of 1998-2002. PUF's are entirely de-identified data files available to selected investigators at Commission on Cancer (CoC) a...

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“…Tumor size difference was calculated as the maximum size reported by pathological examination minus the maximum size reported by MRI. Previous studies have demonstrated a significant difference between mean tumor sizes measured on CT or MRI and pathological examination [11,13,14] . Therefore, mean tumor sizes measured by MRI were compared to those measured by pathological exam to confirm observed discrepancies in our previous report [14] .…”

Section: Discussionmentioning

confidence: 99%

“…Recent data has emerged showing that computed tomography (CT) underestimates tumor size by a median of 7 mm [11] . Advanced MRI sequences have shown only minimal advantages for tumor size delineation over CT [14] . Given this consistent radiographic to pathologic size discrepancy, determining factors that contribute to this discrepancy is important for accurate RT delivery.…”

Section: Introductionmentioning

confidence: 99%

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The influence of time interval between diagnostic image acquisition and operative date on pathologic tumor size in pancreatic adenocarcinoma: implications for local therapy

Dulaney

Hall

Mikell

et al. 2014

JBGC

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Objectives: Computed tomography (CT) and magnetic resonance imaging (MRI) may underestimate pancreatic tumor size, which has important implications for local therapy. Our aim was to determine if tumor growth during the interval between image acquisition and operative date impacted the observed size discrepancy.Methods: Tumor sizes measured on preoperative MRI were compared with gross pathological specimen measurements in 148 patients with surgically resected pancreatic adenocarcinoma. Differences in the measurements were correlated with the interval between date of pre-operative MRI acquisition and date of operation. Differences between tumor size on MRI and pathology reports were compared with respect to the intervening time interval.Results: A total of 148 patients had pre-operative MRI scans and were included in the analysis. The median patient age was 66 years (range: 29 years-86 years). A significant under estimation of 4.5 mm between tumor size measured on preoperative MRI and pathological examination (p < .001) was demonstrated. There was no significant correlation between size discrepancy and time interval from the diagnostic imaging study and the surgical procedure (R 2 = 0.001, p = .72). Conclusions:Time interval between the acquired diagnostic imaging study and operative date appears to have no measureable influence on radiographic to pathologic size discrepancy in pancreatic adenocarcinoma. MRI was again shown to underestimate pancreatic cancer tumor size. Additional exploration into the role of MRI in delineating pancreatic tumor volume with a prospectively designed study is needed to validate these findings.

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Tumor Size on Abdominal MRI Versus Pathologic Specimen in Resected Pancreatic Adenocarcinoma: Implications for Radiation Treatment Planning

Cited by 34 publications

References 19 publications

Conformity analysis to demonstrate reproducibility of target volumes for Margin-Intense Stereotactic Radiotherapy for borderline-resectable pancreatic cancer

Conformity analysis to demonstrate reproducibility of target volumes for Margin-Intense Stereotactic Radiotherapy for borderline-resectable pancreatic cancer

The Influence of Radiation Therapy Dose Escalation on Overall Survival in Unresectable Pancreatic Adenocarcinoma

The influence of time interval between diagnostic image acquisition and operative date on pathologic tumor size in pancreatic adenocarcinoma: implications for local therapy

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