1. Results of Definitive Radiotherapy in Anal Canal Carcinoma
Hsuan-Chih Hsu1, Hong-Hwa Chen2, Chong-Jong Wang1, Eng-Yen Huang1, Chia-Lo Chang2, Ching-Yeh Hsiung1
Department of Radiation Oncology1 and Colorectal Surgery2
Chang Gung Memorial Hospital Kaohsiung

2. Introduction
Before the 1980s, the standard treatment for anal cancer was an abdomino-perineal resection and permanent colostomy, with or without adjuvant radiotherapy.
In Europe, many centers tried to use difinitive radiation for anal cancer in an attempt to preserve sphincter function because of the radioresponsiveness of these cancers.
The addition of fluorouracil and mitomycin chemotherapy as initially described by Nigro et al. has been shown to have a significant benefit with improved local control and disease-free survival for patients with advanced disease.
The purpose of our study was to evaluate the treatment results of primary radiotherapy for anal canal carcinoma.

3. Materials and Methods
Between October 1987 and July 2002, eighteen patients with anal canal carcinoma were treated with radiotherapy alone (5 patients) or radiation plus 2 cycles of concurrent chemotherapy (13 patients).
The stage according to American Joint Committee on Cancer (AJCC) Staging System (2002) wasⅠin 6,Ⅱin 10 andⅢb in 2. (T1N0M0:6; T2N0M0:8; T3N0M0:2; T2N3M0:2)

4. Materials and Methods
Two patients had bilateral inguinal nodal involvement at presentation.
The age ranged from 38 to 74 years, with a median of 58 years.
All patients had at least 27 months of follow-up.
Patients with distant metastases at presentation were excluded.
The characteristics of the patients and tumors were presented in table 1.

5. Table 1. Patient Characteristics
No. of cases
Total Cases 18
Sex
male 5
female 13
Age (years)
≦ 58 9
＞ 58
Stage
stageⅠ 6
stageⅡ 10
stageⅢb 2
Histology subtype
squamous cell carcinoma 15
basaloid 3
Chemotherapy
yes no
Radiation dose
≦ 55.8 Gy
＞ 55.8 Gy

6. Materials and Methods Treatment RT alone: 5 CCRT: 13 T1N0M0: 2

7. Materials and Methods Radiotherapy Initial course: Boost:
Field: AP+PA fields encompassed low pelvis and bilateral inguinal lymph nodes.
Dose: Gy, 1.8 Gy /fraction, 5 times/week.
Boost:
Bilateral fields encompassed tumor site boost to total Gy (median: 55.8 Gy).

8. Materials and Methods Chemotherapy
Thirteen patients received radiation plus 2 cycles of concurrent chemotherapy.
The regimen was continuous infusion fluorouracil (1000 mg/m2 per day for 4 days) plus mitomycin (10-15 mg/m2 ) on the first day of each cycle.

9. Materials and Methods Statistical analysis
We retrospectively evaluated overall survival rate, local control rate and distant metastasis-free rate that were determined by the Kaplan-Meier method.

10. Results Initial clinical response to treatment
Of 18 patients evaluable, initial response to treatment at 4 weeks after treatment showed 16 patients with clinical complete remission (CR) and 2 patients with partial response (PR) (defined as > 50% regression of tumor).
The distribution by treatment
RT alone group: 4 CR, 1 PR
CCRT group: 12 CR, 1 PR.

11. Results
The 5-year overall survival rate, local control rate and distant metastasis-free rate were 61%, 83% and 81%, respectively.
Of 18 patients, three patients (17%) had local failures and 3 patients (17%) developed distant metastases. Isolated local recurrences were observed in 2 patients (11%), isolated metastatic disease without local recurrence in 2 patients (11%), and combined local and metastatic disease in 1 patient (6%).

12. Results
Three patients had distant metastases, liver metastasis was the most common site and occurred in 3 patients (100%).
One patient had liver, retroperitoneal L.N. and bone metastasis.
One patient had liver metastasis.
One patient had liver and retroperitoneal L.N. metastasis.

13. Discussion
At present, curative-intent radiotherapy is the standard first-line treatment. Surgery should be reserved for residual tumor after RT or local tumor recurrence.
Elisabeth DA et al. reported excellent results with RT alone in patients with tumors < 2 cm in length, concurrent chemoradiotherapy should be preferred for tumors ≧ 2 cm in length and for locally advanced tumors.

14. Discussion
In our study, the 5-year overall survival rate, local control rate and distant metastasis-free rate were 61%, 83% and 81%, respectively. The results were similar to those reported by other series.
However, how to improve local control and decrease distant metastasis still should be further explored.