Have a personal or library account? Click to login
Hypofractionated preoperative radiotherapy for high risk soft tissue sarcomas in a geriatric patient population Cover

Hypofractionated preoperative radiotherapy for high risk soft tissue sarcomas in a geriatric patient population

Open Access
|Nov 2021

Figures & Tables

Figure 1

Example of a radiation plan for a thigh sarcoma. The 3D conventional radiotherapy plan shows a good dose coverage for the target volumes (even for this case of the largest tumour in our series with 17 cm) (A). The dose constraints for bones concerning pathologic fractures described below were kept (B).

Figure 2

Starting from the equation for equivalent dose 2 Gy (EQD2) for a hypofractionated radiation regimen in 5 fractions, the quadratic equation for the single dose in five fractions corresponding to the known EQD2 was derived. Solving the quadratic equation leads to the dose per fraction for five fractions corresponding to the given EQD2 (assuming a known α/β value for tumour control or side effects in OARs, respectively). Dose per fraction for the constraints for normofractionated radiotherapy was fixed to 2 Gy, although dose per fraction varies with the number of fractions for the same total dose (e.g. 40 Gy circumferential dose would refer to a dose per fraction of 1.6 Gy for 25 fractions in preoperative radiotherapy or 1.2 Gy for postoperative radiotherapy in 33 fractions). As dose constraints for normofractionated radiotherapy normally are not corrected for number of fractions in clinical plan evaluation, they were not corrected to EQD2 for the transfer to the hypofractionated regimen. constrHFX = constraint for hypofractioanted radiotherapy. constrNFX = constraint for normofractioanted radiotherapy.

Figure 3

Radiation planning parameters were evaluated for seven of nine patients with sarcomas of the lower extremity. For bone constraints concerning pathologic fracture the whole femur or the whole tibia were contoured for thigh and calf sarcomas, respectively. Black bars indicate the median values, red bars indicate the assumed constraints as described in Tbl 2 and in the main text (for bone with α/β = 1.8 Gy, worst case scenario). Gross tumour volume (GTV) coverage was reached in all cases. D98 for clinical target volume (CTV) fell short in one patient with a large calf sarcoma with a CTV reaching the skin in large areas. Re-calculated dose constraints for pathologic fracture were not reached in any case.

Dose constraints

Constraints
Bone α/β = 1.8 Gyα/β = 2.8 Gy
V40 < 64%V23.4 < 64%V24.8 < 64%[18]
Dmean < 37 GyDmean < 22.4Dmean < 23.6 Gy[18]
D2 < 59 GyD2 < 29.3 GyD2 < 31.3 Gy[18]
Circumferential < 50 GyCircumferential < 26.4 GyCircumferential < 28.3 GyInstitutional standard

Soft tissue α/β = 2.0 Gy

Circumferential < 40 GyCircumferential < 23.7 Gy Institutional standard

Patient characteristics and postoperative complications

Age at diagnosisLocalisationSize [cm]HistologyGradingDays to resectionResection statusPostoperative complicationFollow up
85forearm7.5NOS2451hematomaalive, NED
91lower leg5.4NOS no surgery lost to follow up
82thigh7.0myxofibrosarcoma2–3250 alive, NED
84forearm6.0epitheliod myxofibrosarcoma3180 alive, NED
91thigh5.5NOS3152 local and distant recurrence
79thoracic wall7.7liposarcoma2290 alive, NED
80gluteus10.0NOS3300 alive, NED
84thigh3.7leiomyosarcoma3340 alive, NED
83thigh10.0liposarcoma3211wound healing complicationlocal and distant recurrence
80thigh8.0NOS3310wound healing complication, seromaalive, distant recurrence lower leg, curative treatment
90thigh8.5leiomyosarcoma2290wound healing complicationalive, NED
85axilla9.2liposarcoma2311 alive, NED
82thigh17.0liposarcoma2230 alive, NED
87thoracic wall5.0NOS3200 alive, NED
82thoracic wall9.0NOS3230wound healing complicationalive, NED
91upper arm5.2NOS3310 recurrence distant
81thigh8.3myxoid fibrosarcoma3310 alive, NED
81upper arm8.3NOS2320 alive, NED
DOI: https://doi.org/10.2478/raon-2021-0038 | Journal eISSN: 1581-3207 | Journal ISSN: 1318-2099
Language: English
Page range: 459 - 466
Submitted on: May 18, 2021
|
Accepted on: Aug 17, 2021
|
Published on: Nov 19, 2021
In partnership with: Paradigm Publishing Services
Publication frequency: 4 issues per year

© 2021 Vlatko Potkrajcic, Frank Traub, Barbara Hermes, Marcus Scharpf, Jonas Kolbenschlag, Daniel Zips, Frank Paulsen, Franziska Eckert, published by Association of Radiology and Oncology
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.