The study included 3670 patients, of whom 7.7% had RCC and 84.3% had Wilms tumor. Compared with the other tumor types, patients with RCC had an older median age (16 vs 3), were more likely to have unilateral laterality, and to be of non-white race. RCC tumors also had a significantly smaller mean size (6.5 cm vs 10.6 cm), and were associated with localized SEER stage (59.3% vs 44.3%).

“Age was a very important distinguishing factor,” Dr Shuch said. “Once you get over around age 12, the majority of tumors are going to be RCC, rather than some of the more common ones seen in children at an earlier age.”


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In fact, the age-adjusted incidence rate for RCC increased with age and was highest at age 19. RCC was significantly associated with smaller tumor size, with odds ratio (OR) of 0.981 per 1 cm increase in diameter. Other factors included increasing age, which had an OR of 1.52 per 1-year age increase, black race (black vs white, OR, 2.61), and SEER stage (distant vs localized, OR, 0.320).

Using these results, the researchers developed a nomogram to identify predictive factors for RCC. It was found that age and tumor size were the most significant factors for predicting RCC.

“Clinicians need to keep this in mind and should not treat all pediatric and adolescent renal tumors the same,” Dr Shuch said. “It raises awareness in terms of distribution of disease and in whom they should have a higher suspicion of RCC.”

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Dr Shuch said that there should be further efforts to expand on the use of imaging prediction for renal tumor histology.

“Since there is concern about the use of biopsy in these patients and there are no validated biomarkers, imaging is extremely important,” Dr Shuch said. “Besides using our clinical predictive nomogram, that, as well as potential imaging modalities predicting histology, would be very useful to move the field forward to get children and young adults the appropriate treatment for their disease.” 

Reference

  1. Syed JS, Nguyen KA, Wu CQ, et al. Distinguishing pediatric and adolescent renal cell carcinoma from other renal malignancies. Pediatr Blood Cancer. 2016 Nov 2. doi: 10.1002/pbc.26315 [Epub ahead of print]