Clinical outcome of adjuvant treatment of endometrial cancer using aperture-based intensity-modulated radiotherapy.
OBJECTIVE
To assess disease control and acute and chronic toxicity with aperture-based intensity-modulated radiotherapy (AB-IMRT) for postoperative pelvic irradiation of endometrial cancer.


METHODS
Between January and July 2005, after hysterectomy for endometrial cancer, 15 patients received 45 Gy to the pelvis using AB-IMRT. The AB-IMRT plans were generated by an in-house treatment planning system (Ballista). The AB-IMRT plans were used for treatment and were dosimetrically compared with three other approaches: conventional four-field, enlarged four-field, and beamlet-based IMRT (BB-IMRT). Disease control and toxicity were prospectively recorded and compared with retrospective data from 30 patients treated with a conventional four-field technique.


RESULTS
At a median follow-up of 27 months (range, 23-30), no relapse was noted among the AB-IMRT group compared with five relapses in the control group (p = 0.1). The characteristics of each group were similar, except for the mean body mass index, timing of brachytherapy, and applicator type used. Patients treated with AB-IMRT experienced more frequent Grade 2 or greater gastrointestinal acute toxicity (87% vs. 53%, p = 0.02). No statistically significant difference was noted between the two groups regarding the incidence or severity of chronic toxicities. AB-IMRT plans significantly improved target coverage (93% vs. 76% of planning target volume receiving 45 Gy for AB-IMRT vs. conventional four-field technique, respectively). The sparing of organs at risk was similar to that of BB-IMRT.


CONCLUSIONS
The results of our study have shown that AB-IMRT provides excellent disease control with equivalent late toxicity compared with the conventional four-field technique. AB-IMRT provided treatment delivery and quality assurance advantages compared with BB-IMRT and could reduce the risk of second malignancy compared with BB-IMRT.
Bouchard
Myriam
M
Département de Radio-oncologie et Centre de Recherche de L'Hôtel-Dieu de Québec, Centre Hospitalier Universitaire de Québec, L'Hôtel-Dieu de Québec, Québec, QC, Canada.
Nadeau
Sylvain
S
Gingras
Luc
L
Raymond
Paul-Emile
PE
Beaulieu
Frédéric
F
Beaulieu
Luc
L
Fortin
André
A
Germain
Isabelle
I
D000368:Aged; D001853:Bone Marrow / Q000528:radiation effects; D001918:Brachytherapy / Q000009:adverse effects*; D018572:Disease-Free Survival; D016889:Endometrial Neoplasms / Q000532:radiotherapy* / Q000601:surgery; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007044:Hysterectomy; D007422:Intestines / Q000528:radiation effects; D008875:Middle Aged; D010865:Pilot Projects; D011446:Prospective Studies; D011829:Radiation Dosage; D011832:Radiation Injuries / Q000150:complications*; D011879:Radiotherapy Dosage; D018714:Radiotherapy, Adjuvant; D050397:Radiotherapy, Intensity-Modulated / Q000009:adverse effects*; D012007:Rectum / Q000528:radiation effects; D016896:Treatment Outcome; D001743:Urinary Bladder / Q000528:radiation effects