In a cohort of patients with papillary renal cell carcinoma (RCC), those with the type II subtype were more likely than those with the type I subtype to have a higher disease stage, according to results of a retrospective analysis published in Scientific Reports.
Accounting for up to 20% of cases of RCC, papillary RCC is the second most common RCC following clear cell RCC. In addition, 2 subtypes of papillary RCC have been identified, type I and type II, although whether the subtype of papillary RCC influences patient prognosis remains unclear. Furthermore, most of the previous studies on papillary RCC were conducted in Europe and the US with predominantly White patients.
The aim of this study was to examine clinicopathologic characteristics of type I and type II papillary RCC in Chinese patients with the disease, and to investigate whether any of these factors are independently associated with patient prognosis.
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Of the 102 patients with papillary RCC included in this analysis, the disease was classified as type I and type II in 42 and 60 patients, respectively.
At baseline, compared with patients with type I papillary RCC, those with type II papillary RCC were significantly more likely to have disease characterized by a higher pathologic T stage (P =.003), higher pathologic N stage (P =.010), and higher stage group (P =.011). In addition, more patients with type II compared with type I disease had higher grade disease according to the World Health Organization/International Society of Urologic Pathologists (WHO/ISUP) classification system (P <.001).2
At a median follow-up of 61.4 months, a survival analysis of evaluable patients showed 5-year cancer-specific survival (CSS) rates of 95.2% and 75.7% (P =.021) for those with type I and type II papillary RCC, respectively. However, when a separate analysis including only those evaluable patients with stage I/II disease was conducted, no significant difference in 5-year CSS rate (P =.214) was noted between those with type I and type II papillary RCC.
“Both type I and type II similarly have good prognosis,” the study investigators stated. They also commented that the finding that the distinction between type I and type II papillary RCC was not predictive of survival was consistent with results of some other recent studies conducted in the U.S. and Europe.
Furthermore, on multivariate analysis, only stage grouping was found to independently predict survival. The hazard ratio for death was 90.91 (95% CI, 5.35-999.95; P =.002) for those with stage III/IV compared with stage I/II disease.
In their concluding remarks, the study investigators noted that “compared with type I [papillary] RCC, type II had higher pathological T, N stage, and WHO/ISUP grading. However, it was the Stage grouping that made a great difference to oncological outcomes, rather than the subtype of [papillary] RCC.”
References
- Pan H, Ye L, Z Q, et al. The effect of the papillary renal cell carcinoma subtype on oncological outcome. Sci Rep. Published online December 3, 2020. doi:10.1038/s41598-020-78174-9
- Warren AY, Harrison D. WHO/ISUP classification, grading and pathological staging of renal cell carcinoma: standards and controversies. World J Urol. 2018;36:1913-1926. doi:10.1007/s00345-018-2447-8
