Measuring levels of C-reactive protein (CRP) after nephrectomy can help to identify patients with renal cell carcinoma (RCC) who are likely to progress to metastasis and death. This is the main conclusion of new work by a group based in Atlanta, Georgia.

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Despite the fact that most people with RCC present with localized disease, 30% go on to develop metastases, even after potentially curative nephrectomy. A method of identifying these patients would be useful in determining which should undergo further treatment and receive more-intensive follow-up.

CRP is an inflammatory marker which is produced in response to cytokines, including interleukin 6. CRP has previously been mooted as a marker of RCC progression, as increased levels of both interleukin 6 and CRP are associated with higher tumor stage and grade, and with metastasis. Previously, studies have focused on preoperative CRP measurement. However, the Atlanta-based group, led by Viraj Master at Emory University, noticed that patients with elevated postoperative CRP levels tended to have an increased risk of metastasis, regardless of their preoperative CRP concentration.

They followed 110 patients for 1 year after potentially curative nephrectomy for clear-cell RCC. Participants were divided into two groups based on T stage; T1–2 and T3. CRP levels determined before nephrectomy were compared with those measured 1 month after surgery.

Within the year that the patients were followed, 16% developed metastases and 6% died. Mean postoperative CRP levels were markedly higher for the patients with poor outcome—69.1 mg/l in the metastatic group (compared with 5.3 mg/l in the nonmetastatic group) and 89.3 mg/l for patients who went on to die from their cancer (compared with 10.9 mg/l for those who survived).

Multivariate analysis showed that T stage and postoperative CRP were the only variables significantly associated with 1-year overall survival. In addition, the odds ratio for both metastasis and mortality increased with increasing postoperative CRP levels. Although preoperative CRP was also a predictor of these outcomes, it ceased to be so after adjusting for postoperative levels.

The authors are quick to point out that postoperative CRP should not replace T stage as a marker of RCC outcome. It does, however, have adjunctive potential. As CRP level is commonly measured as part of routine postoperative blood workup in hospital inpatients, it could prove to be a useful and cost-effective tool for the identification of those with aggressive disease.