title: Growth pattern of serous cystic neoplasms of the pancreas: observational study with long-term magnetic resonance surveillance and recommendations for treatment.
abstract: OBJECTIVE
  The natural history and growth pattern of pancreatic serous cystic neoplasms (SCNs) are not well understood. This study was designed in order to get insight into the growth rate of SCNs and to suggest recommendations for their management.
  
  
  METHODS
  Patients with well-documented incidentally discovered or minimally symptomatic SCNs who underwent yearly surveillance MRI were analysed using a linear mixed model. The growth rate and the effects of different fixed factors (sex, personal history of other non-pancreatic malignancies, radiological pattern, clinical presentation, tumour site) and random factors (age and tumour diameter at the time of diagnosis) on tumour growth were investigated.
  
  
  RESULTS
  Study population consisted of 145 patients. Estimated overall mean growth rate was 0.28 cm/year, but the growth curve analysis showed a different trend between the first 7 years after the baseline evaluation (growth rate of 0.1 cm/year) and the subsequent period (years 7 to 10, growth rate of 0.6 cm/year, p<0.0001). Tests for fixed effects demonstrated that an oligocystic/macrocystic pattern and a personal history of other tumours are significant predictors of a more rapid mean tumour growth (p<0.0001 and 0.022, growth rates of 0.34 cm/year). Furthermore, tumour growth significantly increased with age (p = 0.0001).
  
  
  CONCLUSIONS
  Overall, SCNs grow slowly, and an initial non-operative approach is feasible in all the asymptomatic or minimally symptomatic patients. The oligocystic/macrocystic variant, a history of other non-pancreatic malignancies and patients' age impact on tumour growth. In any case, a significant growth is unlikely to occur before 7 years from the baseline evaluation. Tumour size at the time of diagnosis should not be used for decisional purposes.
authors.affiliation: Department of Surgery, General Surgery B, GB Rossi Hospital, Ple LA Scuro 10, 37134 Verona, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Malleo
authors.forename: Claudio
authors.initials: C
authors.lastname: Bassi
authors.forename: Roberto
authors.initials: R
authors.lastname: Rossini
authors.forename: Riccardo
authors.initials: R
authors.lastname: Manfredi
authors.forename: Giovanni
authors.initials: G
authors.lastname: Butturini
authors.forename: Marta
authors.initials: M
authors.lastname: Massignani
authors.forename: Marina
authors.initials: M
authors.lastname: Paini
authors.forename: Paolo
authors.initials: P
authors.lastname: Pederzoli
authors.forename: Roberto
authors.initials: R
authors.lastname: Salvia
mesh_terms: D000368:Aged; D018293:Cystadenoma, Serous / Q000473:pathology* / Q000628:therapy; D005260:Female; D006801:Humans; D016014:Linear Models; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010190:Pancreatic Neoplasms / Q000473:pathology* / Q000628:therapy; D011159:Population Surveillance; D047368:Tumor Burden