Fræðigrein

Introduction: The incidence of renal cell carcinoma (RCC) is rising in Iceland. This has been attributed to increased diagnostic activity, such as abdominal imaging of unrelated diseases, rather than changes in the behavior of the disease. The aim of this study was to compare RCCs diagnosed in living patients and at autopsy, but also to investigate the relationship between the incidence of RCC and autopsy findings.

Material and Methods: RCC found incidentally in individuals at autopsy was compared to patients diagnosed alive over three decades in Iceland (1971-2005). Stage at diagnosis and tumor histology was reviewed.

Results: 110 tumors were diagnosed at autopsy with a rate of 7.1/1000 autopsies. When compared to patients diagnosed alive (n = 913) the mean age at diagnosis was higher in the autopsy group (74.4 vs. 65 yrs.) while male to female ratio and laterality was similar. Tumors found at autopsy were smaller (3.7 vs. 7.3 cm), at lower stage (88% at stage I+II vs. 42%) and at lower tumor grade (85% at grade I+II vs. 56%). A difference, although smaller, is present when the autopsy detected cases are compared to only incidentally detected RCCs in living patients. Furthermore the autopsy detected tumors were more frequently of papillary cell type (21% vs. 8%). After correcting for declining autospy rate (>50%), a slight trend for a reduced rate of autopsy dectected RCC cases was seen during the last 10 years of the period but the difference was not significant.

Conclusion: RCCs diagnosed at autopsy are at a lower stage and tumor grade than in patients diagnosed alive. The autopsy-rate is declining in Iceland with fewer RCCs found per autopsy. After correcting for the decline in autopsy rate, the rate of RCC detected at autopsy is relatively unchanged. The increase in incidence of RCC is therefore not explained by findings at autopsy.

 

Figure 1. Number of autopsy-diagnosed RCCs (blue columns) compared to autopsy rate in Iceland, between 1971 and 2005 (red line).

Figure 2. Rate of autopsy-diagnosed RCCs per 1000 autopsies, in 5-year periods between 1971 and 2005

 

Table 1.   TNM stage of autopsy diagnosed RCCs in Iceland 1971-2005. Number of cases and percentages in parenthesis.

 

TNM-group stage	n (%)
I	89 (83.2)
II	5 (4.7)
III	6 (5.6)
IV	7 (6.5)

^*Information missing for 3 tumors