FOBT compared to FIT in reducing colorectal cancer (CRC) incidence.

Abstract

e18119 Background: It is thought that CRC incidence reduction (IR) and cancer mortality reduction (CMR) associated with screening (Scr) with colonoscopy (CS) and flexible sigmoidoscopy (FS) are derived from adenoma detection as opposed to invasive cancer and down-staging. While traditionally FIT is felt to be superior to FOBT, and neither one is empirically linked to IR, if a positive Scr is followed by CS the subjects are expected to accrue the IR and CMR benefits of CS. Methods: To test this hypothesis, a Markov model was built to represent the CRC incidence and its natural history in the US general population. Study perspective was societal and costs and effects were discounted (Dis) at 3%. 8 Scr strategies (ST) were compared to No Scr. Dis Life Years (LY), IR, CMR, and Dis costs of Scr and total costs of care were measured. Incremental cost effectiveness ratios (ICERs) were calculated. Results: FOBT or FIT resulted in IR and CMR due to diagnostic CS prompted by false positive (FP) Scr. Despite being more sensitive (.82 vs .64) and specific (.97 vs .90) FIT is inferior to FOBT in IR (6% vs 12%) and CMR (12% vs 17%). Compared to No Scr, FOBT 2 was the most cost effective (CE) ST. When FS was included, it became the most CE ST with ICER of $32K, and when CS was included, it dominated all other STs. Conclusions: Stool testing can reduce CRC incidence. FIT detects more cancers than FOBT. Yet, it is inferior to FOBT in IR, MR, and LY gained underlining the importance adenoma detection and removal as a result higher FP rates of FOBT. Strategy Comparative Effectiveness Costs Cost Effectiveness Status (Rank-ICER $) Dis LY CRC IR (%) CMR (%) Cancer Care Scr Without CS or FS With FS With CS and FS No Scr 15.205 0 0 3415 0 D D D ST 1: FOBT 15.215 12 17 3078 86 D D D ST 2: FIT 15.211 6 12 3180 123 D D D ST 3: FOBT + FS 15.217 14 19 3012 158 D D D ST 4: FIT + FS 15.214 8 14 3106 232 D D D ST 5: FOBT 2 15.218 12 20 2979 75 U (1-0) U (1- 0) D ST 6: FIT 2 15.215 5 14 3093 93 D D D ST 7: FOBT 2 + FS 15.219 13 21 2949 178 U (2 - 67,297) D D ST 8: FIT 2 + FS 15.217 7 17 3026 230 D D D FS 15.221 11 21 2875 270 U (1- 32,229) D CS 15.227 23 34 2335 526 U (1- 0) FOBT: Fecal Occult Blood Test, FIT: Fecal Immunochemical Test. Stool tests are done annually or at the interval listed. D: Dominated. U: Undominated.