Squamous cell carcinoma of the anal canal: patterns and predictors of failure and implications for intensity-modulated radiation treatment planning.
OBJECTIVE
Intensity-modulated radiation treatment (IMRT) is increasingly used in the treatment of squamous cell carcinoma of the anal canal (SCCAC). Prevention of locoregional failure (LRF) using IMRT requires appropriate clinical target volume (CTV) definition. To better define the CTV for IMRT, we evaluated patterns and predictors of LRF in SCCAC patients given conventional radiation treatment.


METHODS
We reviewed records of 180 SCCAC patients treated with conventional radiation with or without chemotherapy at our institution between January 1990 and March 2007. All patients received radiation; the median primary tumor dose was 45 Gy. A total of 173 patients also received mitomycin-based chemotherapy.


RESULTS
Median follow-up was 40 months. Actuarial 3-year colostomy-free survival was 89% and overall survival (OS) 88%. Actuarial 3-year LRF was 23%. A total of 45 patients had LRF, with 35 (78%) occurring locally in the primary site (25 local only, 10 local and regional); however, 20 (44%) had regional components of failure within the pelvis or inguinal nodes (10 regional only, 10 local and regional). Cumulative sites of LRF (patients may have one or more site of failure) were as follows: primary, 35; inguinal, 8; external perianal, 5; common iliac, 4; presacral, 3; distal rectum, 2; external iliac, 2; and internal iliac, 2. All patients with common iliac failure had cT3 or N+ disease.


CONCLUSIONS
The observed patterns of failure support inclusion of the inguinal and all pelvic nodal groups in the CTV for IMRT. In patients with advanced tumor or nodal stage, common iliac nodes should also be included in the CTV.
Wright
Jean L
JL
Department of Radiation Oncology, University of Miami, Miami, FL 33133, USA. jwright3@med.miami.edu
Patil
Sujata M
SM
Temple
Larissa K F
LK
Minsky
Bruce D
BD
Saltz
Leonard B
LB
Goodman
Karyn A
KA
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D001005:Anus Neoplasms / Q000188:drug therapy / Q000401:mortality / Q000517:prevention & control / Q000532:radiotherapy*; D002294:Carcinoma, Squamous Cell / Q000188:drug therapy / Q000401:mortality / Q000517:prevention & control / Q000532:radiotherapy*; D005260:Female; D005472:Fluorouracil / Q000008:administration & dosage; D006801:Humans; D015182:Lymphatic Irradiation; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D016685:Mitomycin / Q000008:administration & dosage; D009364:Neoplasm Recurrence, Local / Q000517:prevention & control; D009367:Neoplasm Staging; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*; D017211:Treatment Failure; D047368:Tumor Burden
D016685:Mitomycin; D005472:Fluorouracil