Definition and validation of a reference target volume in early stage node-positive cervical carcinoma, based on lymphangiograms and CT-scans.
OBJECTIVE
To establish a reference planning target volume for postoperative radiotherapy in stage Ib and IIa N+ cervical carcinoma, based on 47 lymphangiograms and 15 CT-scans.


METHODS
Radiation oncologists (n=17) from all radiotherapy institutes in The Netherlands were asked to define the clinical target volume (CTV) and planning target volume (PTV), and to delineate (on simulation films) the radiotherapy treatment portals following a radical hysterectomy with lymph node dissection for an early stage cervical carcinoma with positive iliac lymph nodes. A reference PTV was defined by using 47 normal lymphangiograms and CT-data of the pelvis from 15 patients who underwent surgery for cervical carcinoma. The simulation films were digitized and evaluated for adequacy in covering the PTV, previously individually determined by the radiation oncologists. Subsequently, the simulation films were also evaluated for adequacy in covering the reference PTV.


RESULTS
Large variations were observed in the portals used and in treatment techniques. From the digitized films, it appeared that in 50% of the cases the defined PTV was not covered adequately. Furthermore, 71% of the treatment plans would not cover the lateral borders of the reference PTV sufficiently.


CONCLUSIONS
There appears to be no consensus on the target volumes to be irradiated in postoperative radiotherapy of early stage cervical carcinoma. When a PTV defined on the basis of lymphangiograms and CT-data is taken as a reference, 71% of the treatment plans would not cover this PTV adequately. These findings indicate the need for a consensus in the design of standardized treatment volumes.
van den Berg
H A
HA
Department of Radiation Oncology, Daniel den Hoed Cancer Center/Dijkzigt Hospital, University Hospital Rotterdam, Groene Hilledijk 301, 3075 EA, Rotterdam, The Netherlands.
Olofsen-van Acht
M J
MJ
van Santvoort
J P
JP
Seven
M
M
Quint
S
S
Levendag
P C
PC
D002294:Carcinoma, Squamous Cell / Q000000981:diagnostic imaging / Q000532:radiotherapy* / Q000556:secondary / Q000601:surgery; D005260:Female; D006801:Humans; D007044:Hysterectomy; D008197:Lymph Node Excision; D008198:Lymph Nodes / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D008207:Lymphatic Metastasis; D008220:Lymphography; D009367:Neoplasm Staging; D009426:Netherlands; D010388:Pelvis; D011182:Postoperative Care / Q000379:methods*; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D015203:Reproducibility of Results; D014057:Tomography, X-Ray Computed; D002583:Uterine Cervical Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery