Predictors and patterns of recurrence after definitive chemoradiation for anal cancer.
OBJECTIVE
To evaluate patterns of locoregional failure, and predictors of recurrence and survival in patients treated with chemoradiation for anal cancer.


METHODS
Between September 1992 and August 2004, 167 patients with nonmetastatic squamous cell anal carcinoma were treated with definitive chemoradiation. The median dose of radiotherapy was 5500 cGy. Concurrent chemotherapy was given with 5-fluorouracil and cisplatin in 117 patients, 5-fluorouracil and mitomycin C in 24 patients, and other regimens in 26 patients.


RESULTS
The estimated 3-year rates of locoregional control, distant control, disease-free survival, and overall survival were 81%, 88%, 67%, and 84%, respectively. Multivariate analysis showed that higher T stage and N stage independently predicted for a higher rate of locoregional failure; higher N stage and basaloid subtype independently predicted for a higher rate of distant metastasis; and higher N stage and positive human immunodeficiency virus status independently predicted for a lower rate of overall survival. Among the patients who had locoregional failure, 18 (75%) had failure involving the anus or rectum, 5 (21%) had other pelvic recurrences, and 1 (4%) had inguinal recurrence. The 5 pelvic recurrences all occurred in patients with the superior border of the radiotherapy field at the bottom of the sacroiliac joint.


CONCLUSIONS
Trials of more aggressive and innovative locoregional and systemic therapies are warranted in high-risk patients, based on their T and N stages. The majority of locoregional failures involve the anus and rectum, whereas inguinal recurrences occur rarely. Placing the superior border of the radiotherapy field at L5/S1 could potentially reduce pelvic recurrences.
Das
Prajnan
P
Department of Radiation Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, TX 77030, USA. PrajDas@mdanderson.org
Bhatia
Sumita
S
Eng
Cathy
C
Ajani
Jaffer A
JA
Skibber
John M
JM
Rodriguez-Bigas
Miguel A
MA
Chang
George J
GJ
Bhosale
Priya
P
Delclos
Marc E
ME
Krishnan
Sunil
S
Janjan
Nora A
NA
Crane
Christopher H
CH
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001005:Anus Neoplasms / Q000401:mortality* / Q000628:therapy*; D002294:Carcinoma, Squamous Cell / Q000401:mortality* / Q000628:therapy*; D017024:Chemotherapy, Adjuvant / Q000401:mortality*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000401:mortality* / Q000517:prevention & control*; D011379:Prognosis; D018714:Radiotherapy, Adjuvant / Q000401:mortality*; D018570:Risk Assessment / Q000379:methods; D012307:Risk Factors; D016019:Survival Analysis; D015996:Survival Rate; D013781:Texas / Q000453:epidemiology; D016896:Treatment Outcome