A cure model survival analysis of patients affected by small intestinal neuroendocrine neoplasms: the Bologna ENETS center experience

Purpose: The primary end-point was to evaluate the cure fraction. Secondary end-points were to investigate the time to cure, the excess of death risk, the probability of cure and the factors related to these parameters. Methods: Retrospective study of an ENETS database regarding patients affected by Si-NENs. For each patients, clinical, pathological and follow-up data were collected. The survival analysis was made using a novel approach: the cure model approach. Results: The cure fraction was 92.1%. The death risk, time to cure and the probability of cure were 6/1000 person-years, 3.6 years and 98.2%, respectively. The independent factors influencing these parameters were the grading and the R status (P = 0.041 and P = 0.017, respectively). Patients affected by Si-NENs G2 increased the death risk and time to cure respect to Si-NENs G1 (51 versus 6 per 1000 person-years and 5.1 versus 3.6 years, respectively) as well as patients not operated respect to those radically resected (R0/1) (66 versus 1 per 1000 person-years and 4.8 versus 0.4 years, respectively). The probability of cure decreased (88.1 versus 97.8% and 80.4 versus 99.7%, respectively). R2 resection shows better results than no resection. Conclusions: A large portion of patients affected by Si-NENs can be cured. The highest probability of cure regards patients with Si-NENs G1 who underwent to R0/R1 resection; the lower, those with Si-NENs G2 and no resection. R2 resection seems to be preferred respect to no resection.