Table 1.

Select studies evaluating radiation therapy (RT) alone or comparing chemoradiation (CRT) to RT in early-stage anal cancer.

Author	Inclusion	Key Results
Ortholan et al. [20]	69 patients: 12 patients with Tis, 57 patients with T1, all ≤1 cm; 66 received RT, 3 Tis treated with local excision alone	91% local control in RT group; 5-year OS 94%, CFS 85%, and DFS 89%
Fallai et al. [21]	62 patients: 9 stage I, with 8 patients treated with CRT	5-year OS and LRC both 100% for stage I patients
Zilli et al. [22]	146 patients: 29 patients with T1, 117 with T2 disease; RT alone in 71 and CRT in 75	5-year LRC of 75.5% for RT vs. 86.8% for CRT, p = 0.155; 5-year CSS of 88.5% for RT vs. 94.9% for CRT, p = 0.161
De Bari et al. [23]	122 patients: 24 patients with T1, 98 patients with T2; RT alone in 52 and CRT in 70	CRT improved LC on multivariate analysis (RR = 0.34, 95% CI 0.16–0.75, p = 0.007)
Miller et al. [4]	3839 stage I patients: RT alone in 287 and CRT in 3552	CRT associated with a 31% reduction in the risk of death compared to RT alone (HR = 0.69, 95% CI 0.50–0.95, p = 0.023)
Buckstein et al. [3]	299 stage I patients: RT alone in 99 and CRT in 200	After propensity score matching, no difference in OS, CSS, CFS, or DFS between the groups.