| Objectives:To study the incidence,associated factors of multicentricity in renal cell carci-noma and to provide evidence for surgical indications and the optimal margin in nephron sparing surgery(NSS) for renal carcinoma.Methods:1. Thirty-six renal cell carcinoma patients of our hospital were collected from 2007 to 2008. After the samples were fixed in 10% formalin solution, we recorded the tumorous maximal diameter and observed the samples to examine whether there were multifocal carcinoma on the surface. 36 kidneys from radical nephrectomy for RCC were step sectioned at 3 mm intervals and any abnormal tissue was removed, stained with hematoxylin and eosin, and examined for multifocal carcinoma.2. Then on each slice of the samples, parenchyma margin of 0.3,0.5,1.0 and 1.5 cm beyond pseudocapsule,the pseudocapsule and tissues around renal sinus were con-tinuously sectioned and examined for completeness of pseudocapsule and ex-tra-pseudocapsule invasion into parenchyma, vascular and lymph node.3. The any renal carcinoma of extra-pseudocapsule was diagnosed multifocal car-cinoma. 36 kidney samples were classified the group multifocal carcinoma and the group unifocal carcinoma according to whether there were multifocal carcinoma.Results:1 .The incidence of multicentricity: Of the 36 renal cancer samples, 5 were found with satellite cancer, the incidence of multifocality in this group of RCC was 13.9%.2. The associated factors of multicentricity: According to the completeness of pseu-docapsule, the incidence was 4% in the tumors with complete pseudocapsule and 36.4% in those without complete pseudocapsule (P=0.023). The incidence was 50% in the tumors with positive vascular invasion and 6.7% in those with negative vascu-lar invasion (P=0.024). Logistic regression analysis showed that completeness of pseudocapsule and vascular invasion were two significant predictors of multicentric-ity (P=0.029, 0.016). According to the diameters of the primary tumors, incidence of multicentricity was 7.1%and 18.2% in tumors less than 4 cm and more than 4 cm ,which had no significant difference among them (P>0.05). No significant rela-tionship was found between incidence of multicentricity and patients'age, sex, tumor classification, stage, grade, lymph node invasion.3. Distances of extra-pseudocapsule multicentricity from the primary tumors: The distance of three extra-pseudocapsule multicentricity from the primary tumors was 0.3cm. The distance of two extra-pseudocapsule multicentricity from the primary tu-mors was 0.5cm.Conclusions:1. The incidence of multicentricity in this group of patients is 13.9%, which is 7.1% in tumors less than 4 cm.2. The associated factors of multicentricity: Tumor diameter,completenss of pseudo-capsule and vascular invasion are significantly related to the incidence of multicen-tricity. In tumors greater than 4 cm,without complete pseudocapsule or with vascular invasion, the incidence is significantly higher than that in tumors 4 cm or less, with complete pseudocapsule, or without vascular invasion.3. Indication of patient selection for NSS: When the contralateral kidney is nor-mal,NSS should be limited to tumors diameter less than 4 cm. Because of the rela-tively high incidence of multicentricity and extra-pseudocapsule invasion in tumors greater than 4 cm, the risk of local recurrence is much more increased.4. When NSS is considered in patients with RCC, especially those with a normal con-tralateral kidney, partial nephrectomy is preferred to tumor enucleation, because the latter is very liable to leave over tumor in the remnant kidney which may cause local recurrence.5. The optimal margin in NSS for renal cell carcinoma: NSS may be performed by excision of the primary tumor with more than 5 mm of the apparently normal paren-chyma. |
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