Meeting: 2016 ASCO Annual Meeting
Title: FOBT compared to FIT in reducing colorectal cancer (CRC) incidence.



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. StrategyComparative EffectivenessCostsCost Effectiveness Status (Rank-ICER $)DisLYCRC IR (%)CMR (%)CancerCareScrWithout CS or FSWith FSWith CS and FSNo Scr15.2050034150DDDST 1: FOBT15.2151217307886DDDST 2: FIT15.2116123180123DDDST 3: FOBT + FS15.21714193012158DDDST 4: FIT + FS15.2148143106232DDDST 5: FOBT 215.2181220297975U (1-0)U (1- 0)DST 6: FIT 215.215514309393DDDST 7: FOBT 2 + FS15.21913212949178U (2- 67,297)DDST 8: FIT 2 + FS15.2177173026230DDDFS15.22111212875270U (1- 32,229)DCS15.22723342335526U (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.