title: [Small renal cell carcinomas and synchronous metastases].
abstract: The incidence of renal cell carcinoma (RCC) is rising in part due to small tumors (≤4cm) detected incidentally with abdominal imaging. Survival for small RCCs has been regarded as favorable and guidelines recommend partial rather than total nephrecteomy. We studied the frequency of synchronous metastasis in patients with small RCCs in Iceland.
  
  
  
  A retrospective study on 257 patients with RCC ≤4cm out of 1102 RCC patients diagnosed in Iceland 1971-2010. Patients with metastasis were compared to those with localized disease. Hospital charts were reviewed and histology, TNM-stage and disease-specific survival compared between groups.
  
  
  
  The proportion of small tumors increased from 9% in 1971-1980 to 33% in 2001-2010 (p<0,001) and incidental detection increased from 14% to 39% during the same period. Out of the 257 patients with small RCCs, 25 (10%) had synchronous metastases, most frequently in lungs or bones. Patients with metastases were on average 1.9 years older, their tumors were 0.2 cm larger and more often located in the right kidney, their hemoglobin was lower and nuclear grade and T-stage higher. Histology was similar in both groups. Five-year survival of patients with and without metastases was 7 vs. 94%, respectively (p<0.001).
  
  
  
  One out of ten patients with small RCC has synchronous metastases at diagnosis. This is higher than in most previous reports that usually include surgical patients only. Patients with metastases are significantly older, more often symptomatic, their tumor are larger and their prognosis worse. Our results indicate that small RCC is a potentially systemic disease at diagnosis that has to be taken seriously.
authors.affiliation: University of Iceland, Iceland.
authors.forename: Petur Solmar
authors.initials: PS
authors.lastname: Gudjonsson
authors.forename: Elin
authors.initials: E
authors.lastname: Mariusdottir
authors.forename: Helga Bjork
authors.initials: HB
authors.lastname: Palsdottir
authors.forename: Gudmundur Vikar
authors.initials: GV
authors.lastname: Einarsson
authors.forename: Eirikur
authors.initials: E
authors.lastname: Jonsson
authors.forename: Vigdis
authors.initials: V
authors.lastname: Petursdottir
authors.forename: Sverrir
authors.initials: S
authors.lastname: Hardarson
authors.forename: Martin Ingi
authors.initials: MI
authors.lastname: Sigurdsson
authors.forename: Tomas
authors.initials: T
authors.lastname: Gudbjartsson
mesh_terms: D000367:Age Factors; D002292:Carcinoma, Renal Cell / Q000401:mortality / Q000556:secondary*; D018572:Disease-Free Survival; D006801:Humans; D007055:Iceland / Q000453:epidemiology; D033162:Incidental Findings; D007680:Kidney Neoplasms / Q000401:mortality / Q000473:pathology*; D009367:Neoplasm Staging; D011379:Prognosis; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D013997:Time Factors; D047368:Tumor Burden