In-Depth Analysis of Wound Complications Following Preoperative Radiotherapy for Lower

Extremity Soft Tissue Sarcoma Patients

Colleen Dickie MSc, MRT(T)(MR)Assistant Professor, University of Toronto

UHNPrincess Margaret Cancer Centre

Acknowledgements

Joanne Moseley, BMathAnthony M. Griffin, MScAmy Parent, MRT(T), BSc, CMDMichael B. Sharpe, PhDPeter C. Ferguson, MD, FRCSCJay S. Wunder, MD, FRCSCPeter Chung, MD, FRCPCCharles N. Catton, MD, FRCPCBrian O’Sullivan, MD, FRCPC

Princess Margaret Cancer Center

Background

• Phase II preop IG-IMRT trial: Reduced combined modality

morbidities Minimized dose to uninvolved

tissues Adult LE-STS Reduced wound complications (WC)

from 43 % (phase III preop arm) to 30.5 %

O’Sullivan et al. Cancer, 2013 May 15;119(10):1878-84.

Background

GTVPTV

• IMRT Trial priority: target coverage

• Future SF spared if feasible• Overlap of flaps with PTV

was a significant predictor of WC (p = 0.003)

• Superficial PTVs WC• Baldini et al.:

Tumor proximity to skin surface

< 3mm predictor of WC

O’Sullivan et al. Cancer, 2013 May 15;119(10):1878-84.

Baldini et al., Ann Surg Oncol, 2013 May;20(5):1494-9.

FLAPS

Objective

• To retrospectively analyze all the elements of the

volume of skin and subcutaneous tissues used to

close the resection site (surgical flaps - SF) Lower extremity STS

Phase II IMRT PMH trial

• To determine which parameters were associated

with WC

Methods / Materials

• MATLAB / Pinnacle

used to quantify:

Mean SF RT dose

SF Volume

Inclusion of fascia

Tumor to skin proximity

GTV and PTV

PTV

FLAPS

GTVPTV

FLAPS

Methods / Materials• MATLAB used to

quantify:

SF Length

SF Width

Variable thickness

across length /

width of SF

SF and PTV overlapLength

Width

PTV

Methods / Materials

• 18 of 59 (30.5%) patients developed WC in IMRT trial

93 % primary closure (55 of 59) 4 non primary- 1 STSG, 1 rotation flap, rotation flap and

STSG

• 8 patients re-planned for tumor growth 5 developed WC (62.5 %) Analyzed tumor growers separately

ResultsWC No WC P value

Mean dose - SF 33.1 Gy 31.7 Gy 0.43

Mean volume - SF 392.2 cc 237.7 cc 0.001

SF Width (R - L) 2.01 cm 1.70 cm 0.05

SF Length (S - I) 27.5 cm 25.0 cm 0.07

SF Thickness (A - P) 2.02 cm 1.76 cm 0.24

% SF ≥ 30 Gy 65 % 61 % 0.41

Tumor to skin proximity 2.5 mm 2.8 mm 0.38

Fasciocutaneous /Subcutaneous SF

7 / 11 17 / 24 0.796

SF / PTV overlap 19 % 8 % 0.0002

GTV 886.7 cc 491.4 cc 0.004

PTV 2430.3 cc 1451.5 cc 0.0002

8 Growers- RT Dose Map

PTV

1st Plan

RePlan

PTV

• Red = prescribed dose

• Minimal Overlap

• Increased Overlap

• Replan- Significantly greater:

• SF overlap• %SF > 30 Gy• Shorter tumor to skin (2.2

mm)

ResultsWC No WC P value Tumor

GrowersP value

Mean dose - SF 33.1 Gy 31.7 Gy 0.43 39.1 Gy 0.003

Mean volume - SF 392.2 cc 237.7 cc 0.001 318.3 cc 0.59

SF Width (R - L) 2.01 cm 1.70 cm 0.05 1.79 cm 0.99

SF Length (S - I) 27.5 cm 25.0 cm 0.07 28.3 cm 0.35

SF Thickness (A - P) 2.02 cm 1.76 cm 0.24 1.56 cm 0.50

% SF ≥ 30 Gy 65 % 61 % 0.41 85 % 0.002

Tumor to skin proximity 2.5 mm 2.8 mm 0.38 2.2 mm 0.36

Fasciocutaneous /Subcutaneous SF

7 / 11 17 / 24 0.796 3 / 5 0.85

SF / PTV overlap 19 % 8 % 0.0002 42 % 0.00001

GTV 886.7 cc 491.4 cc 0.004 1193.7 cc 0.006

PTV 2430.3 cc 1451.5 cc 0.0002 2744.2 cc 0.009

Conclusions• WC is reduced when:

92 % of SF is proportionally excluded from PTV

• Provides volume estimate for IMRT optimization• Larger GTV / PTVs were associated with WC• Tumor growth may occur at any time during preop

IMRT and may: Increase PTV / SF overlap Increases SF > 30 Gy Increase WC rate

AcknowledgementsJoanne Moseley, BMath

Amy Parent, BSc, MRT(T)Anthony M. Griffin, MScMichael B. Sharpe, PhD

Peter C. Ferguson, MD, FRCSCJay S. Wunder, MD, FRCSCRobert S. Bell, MD, FRCSCPeter Chung, MD, FRCPC

Charles N. Catton, MD, FRCPCBrian O’Sullivan, MD, FRCPC

Princess Margaret Cancer Center