Phase II study of preoperative helical tomotherapy with a simultaneous integrated boost for rectal cancer.
OBJECTIVE
The addition of concomitant chemotherapy to preoperative radiotherapy is considered the standard of care for patients with cT3-4 rectal cancer. The combined treatment modality increases the complete response rate and local control (LC), but has no impact on survival or the incidence of distant metastases. In addition, it is associated with considerable toxicity. As an alternative strategy, we explored prospectively, preoperative helical tomotherapy with a simultaneous integrated boost (SIB).


METHODS
A total of 108 patients were treated with intensity-modulated and image-guided radiotherapy using the Tomotherapy Hi-Art II system. A dose of 46 Gy, in daily fractions of 2 Gy, was delivered to the mesorectum and draining lymph nodes, without concomitant chemotherapy. Patients with an anticipated circumferential resection margin (CRM) of less than 2 mm, based on magnetic resonance imaging, received a SIB to the tumor up to a total dose of 55.2 Gy. Acute and late side effects were scored using the National Cancer Institute Common Terminology Criteria for Adverse Events version 3.0.


RESULTS
A total of 102 patients presented with cT3-4 tumors; 57 patients entered the boost group and 51 the no-boost group. One patient in the no-boost group developed a radio-hypersensitivity reaction, resulting in a complete tumor remission, a Grade 3 acute and Grade 5 late enteritis. No other Grade ≥3 acute toxicities occurred. With a median follow-up of 32 months, Grade ≥3 late gastrointestinal and urinary toxicity were observed in 6% and 4% of the patients, respectively. The actuarial 2-year LC, progression-free survival and overall survival were 98%, 79%, and 93%.


CONCLUSIONS
Preoperative helical tomotherapy displays a favorable acute toxicity profile in patients with cT3-4 rectal cancer. A SIB can be safely administered in patients with a narrow CRM and resulted in a promising LC.
Department of Radiotherapy, Universitair Ziekenhuis Brussel, Vrije Universiteit Brussel, Brussels, Belgium.
Benedikt
B
Engels
Koen
K
Tournel
Hendrik
H
Everaert
Anne
A
Hoorens
Alexandra
A
Sermeus
Nicolas
N
Christian
Guy
G
Storme
Dirk
D
Verellen
Mark
M
De Ridder
D000230:Adenocarcinoma / Q000188:drug therapy / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D059248:Chemoradiotherapy / Q000009:adverse effects / Q000379:methods; D018572:Disease-Free Survival; D019583:Dose Fractionation, Radiation; D005260:Female; D005472:Fluorouracil / Q000627:therapeutic use; D006801:Humans; D007421:Intestine, Small / Q000000981:diagnostic imaging / Q000473:pathology; D008297:Male; D008875:Middle Aged; D011300:Preoperative Care / Q000379:methods; D011446:Prospective Studies; D011832:Radiation Injuries / Q000150:complications / Q000473:pathology; D011838:Radiation-Sensitizing Agents / Q000627:therapeutic use; D011859:Radiography; D061089:Radiotherapy, Image-Guided / Q000379:methods* / Q000401:mortality; D050397:Radiotherapy, Intensity-Modulated / Q000009:adverse effects / Q000379:methods* / Q000401:mortality; D012004:Rectal Neoplasms / Q000188:drug therapy / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D012007:Rectum / Q000473:pathology / Q000528:radiation effects; D012074:Remission Induction; D016896:Treatment Outcome; D001743:Urinary Bladder / Q000000981:diagnostic imaging / Q000473:pathology
D011838:Radiation-Sensitizing Agents; D005472:Fluorouracil