Impact of thymidine phosphorylase-expressing macrophages for surgical margin in partial nephrectomy
Hongming Liu1, Tatsuya Takayama, Hiroshi Ogawa
1Department of Urology, Hamamatsu University School of Medicine, Hamamatsu, Japan.
Objectives:
We investigated the relationship between the surgical margin in partial nephrectomy (PN) and thymidine phosphorylase (TP)-expressing macrophages in peritumoral tissue of renal cell carcinoma (RCC).
Methods:
In 46 patients who underwent radical nephrectomy, we measured TP protein levels in tumor tissue, peritumoral tissue and normal tissue, and conducted immunohistochemical staining for TP and macrophages. In addition, we prospectively conducted PN with a 5-mm margin in 11 patients with pT1a RCC.
Results:
The TP protein level and TP-positive macrophages were correlated with T classification, histological grade, mode of infiltration and venous invasion. However, for pT1 RCC, TP-positive macrophages in pT1a were significantly lower than in pT1b (p = 0.0140), while there was no significant difference in TP protein levels between pT1a and pT1b. No surgical margin was positive in 11 patients who underwent PN with a 5-mm margin, and no patient had local recurrence or distant metastasis during follow-up.
Conclusions:
The TP protein level and TP-positive macrophages in the peritumor area are thought to be associated with tumor progression in RCC, while a similar relationship was not found in pT1a RCC. These data suggest that a 5-mm margin might be safe to reduce the risk of local recurrence when PN is performed for treatment of solitary pT1a RCC.
Insights
Partial nephrectomy (PN) for solitary pT1a renal cell carcinoma (RCC) with a 5-mm margin appears safe. Thymidine phosphorylase (TP)-positive macrophages in peritumoral tissue may indicate tumor progression in RCC, but not specifically in pT1a RCC.
Area of Science:
- Oncology
- Immunology
- Surgical Pathology
Background:
- Thymidine phosphorylase (TP) and TP-expressing macrophages are implicated in renal cell carcinoma (RCC) progression.
- The role of surgical margins in partial nephrectomy (PN) for localized RCC requires further elucidation.
Purpose of the Study:
- To investigate the association between surgical margins in PN and peritumoral thymidine phosphorylase (TP)-expressing macrophages in RCC.
- To evaluate the safety and efficacy of a 5-mm surgical margin in PN for pT1a RCC.
Main Methods:
- TP protein levels and macrophage infiltration were assessed via immunohistochemistry in tissues from 46 patients undergoing radical nephrectomy.
- A prospective cohort of 11 patients with pT1a RCC underwent PN with a 5-mm margin.
Main Results:
- TP protein levels and TP-positive macrophages correlated with RCC T classification, grade, infiltration, and venous invasion.
- TP-positive macrophages were significantly lower in pT1a RCC compared to pT1b RCC, with no difference in TP protein levels.
- PN with a 5-mm margin resulted in no positive margins, local recurrence, or distant metastasis in the pT1a RCC cohort during follow-up.
Conclusions:
- TP protein and TP-positive macrophages in the peritumor area are linked to RCC tumor progression, but this association is not evident in pT1a RCC.
- A 5-mm surgical margin in PN for solitary pT1a RCC appears safe and may reduce local recurrence risk.
