Postoperative intensity-modulated radiotherapy in low-risk endometrial cancers: final results of a Phase I study.
OBJECTIVE
To determine the maximum tolerated dose of short-course radiotherapy (intensity-modulated radiotherapy technique) to the upper two thirds of the vagina in endometrial cancers with low risk of local recurrence.


METHODS
A Phase I clinical trial was performed. Eligible patients had low-risk resected primary endometrial adenocarcinomas. Radiotherapy was delivered in 5 fractions over 1 week. The planning target volume was the clinical target volume plus 5 mm. The clinical target volume was defined as the upper two thirds of the vagina as evidenced at CT simulation by a vaginal radio-opaque device. The planning target volume was irradiated by a seven-field intensity-modulated radiotherapy technique, planned by the Plato Sunrise inverse planning system. A first cohort of 6 patients received 25 Gy (5-Gy fractions), and a subsequent cohort received 30 Gy (6-Gy fractions). The Common Toxicity Criteria scale, version 3.0, was used to score toxicity.


RESULTS
Twelve patients with endometrial cancer were enrolled. Median age was 58 years (range, 49-74 years). Pathologic stage was IB (83.3%) and IC (16.7%). Median tumor size was 30 mm (range, 15-50 mm). All patients completed the prescribed radiotherapy. No patient experienced a dose-limiting toxicity at the first level, and the radiotherapy dose was escalated from 25 to 30 Gy. No patients at the second dose level experienced dose-limiting toxicity. The most common Grade 2 toxicity was gastrointestinal, which was tolerable and manageable.


CONCLUSIONS
The maximum tolerated dose of short-course radiotherapy was 30 Gy at 6 Gy per fraction. On the basis of this result, we are conducting a Phase II study with radiotherapy delivered at 30 Gy.
Macchia
Gabriella
G
Radiotherapy Unit, John Paul II Center for High Technology Research and Education in Biomedical Sciences, Catholic University, Campobasso, Italy. gmacchia@rm.unicatt.it
Cilla
Savino
S
Ferrandina
Gabriella
G
Padula
Gilbert D A
GD
Deodato
Francesco
F
Digesù
Cinzia
C
Caravatta
Luciana
L
Picardi
Vincenzo
V
Corrado
Giacomo
G
Piermattei
Angelo
A
Valentini
Vincenzo
V
Cellini
Numa
N
Scambia
Giovanni
G
Morganti
Alessio Giuseppe
AG
D000230:Adenocarcinoma / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D000368:Aged; D019583:Dose Fractionation, Radiation; D004307:Dose-Response Relationship, Radiation; D016889:Endometrial Neoplasms / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D005260:Female; D006801:Humans; D020714:Maximum Tolerated Dose; D008875:Middle Aged; D011184:Postoperative Period; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*; D047368:Tumor Burden