Complete pathological responses in locally advanced rectal cancer after preoperative IMRT and integrated-boost chemoradiation.
OBJECTIVE
To analyze the efficacy and safety of a new preoperative intensity-modulated radiotherapy (IMRT) and integrated-boost chemoradiation scheme.


METHODS
In all, 74 patients were treated with IMRT and concurrent standard dose capecitabine. The dose of the planning target volume (PTV) encompassing the tumor, mesorectum, and pelvic lymph nodes was 46 Gy in 23 fractions; the boost PTV, at a dose of 57.5 Gy in 23 fractions, included the macroscopic primary tumor and pathological lymph nodes. The patients underwent surgery 6-8 weeks after chemoradiation.


RESULTS
The complete treatment data of 72 patients were analyzed. Tumor downstaging was achieved in 55 patients (76.38 %) and node downstaging in 34 (47.2 %). In 22 patients (30.6 %), there was complete pathological response (ypCR). The circumferential resection margin was free of tumor in 70 patients (97.2 %). The 3-year estimated overall survival and disease-free survival rates were 95.4 and 85.9 % respectively, and no local relapse was found; however, ten patients (13.8 %) developed distant metastases. High pathologic tumor (pT) downstaging was shown as a favorable prognostic factor for disease-free survival. No grade 4 acute radiotherapy-related toxicity was found.


CONCLUSIONS
The IMRT and integrated-boost chemoradiation scheme offered higher rates of ypCR and pT downstaging, without a significant increase in toxicity. The circumferential margins were free of tumors in the majority of patients. Primary tumor regression was associated with better disease-free survival.
Department of Radiation Oncology, Hospital Universitario Sanchinarro, Madrid, Spain, ohernando@hmhospitales.com.
Ovidio
O
Hernando-Requejo
Mercedes
M
López
Antonio
A
Cubillo
Almudena
A
Rodriguez
Raquel
R
Ciervide
Jeannette
J
Valero
Emilio
E
Sánchez
Mariola
M
Garcia-Aranda
Jesus
J
Rodriguez
Guillermo
G
Potdevin
Carmen
C
Rubio
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D059248:Chemoradiotherapy; D003131:Combined Modality Therapy; D018572:Disease-Free Survival; D019583:Dose Fractionation, Radiation; D005260:Female; D006801:Humans; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D009361:Neoplasm Invasiveness / Q000473:pathology*; D009367:Neoplasm Staging; D011379:Prognosis; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*; D012004:Rectal Neoplasms / Q000628:therapy*; D016019:Survival Analysis