The effect of discrepancy between radiologic size and pathologic tumor size in renal cell cancer

Zhang et al. SpringerPlus (2016) 5:899 DOI 10.1186/s40064-016-2645-z Open Access RESEARCH The effect of discrepancy between radiologic size and pathologic tumor size in renal cell cancer Ning Zhang1,2†, Yishuo Wu1,2†, Jianqing Wang1,2, Jianfeng Xu1,2, Rong Na1,2* and Xiang Wang1,2* Abstract To investigate the difference between preoperative radiologic tumor size (RTS) and postoperative pathologic tumor size (PTS) in patients who underwent nephrectomy for renal cell carcinoma. We retrospectively reviewed 257 patients who received preoperative computed tomography (CT) before radical or partial nephrectomy for renal cell carcinoma from January 2010 to May 2015 in Huashan Hospital, Shanghai. RTS was defined as the largest diameter of tumor measured by CT and PTS as the largest diameter of tumor measured in the surgical specimens. Among all subjects, mean RTS was larger than PTS (4.57 ± 2.15 vs. 4.02 ± 2.15 cm, P = 0.004) with a discrepancy of 0.55 cm. When the patients were categorized according to T stage, the mean RTS was greater than PTS in the following groups: ≤4 cm group (2.90 vs. 2.59 cm, P = 0.02), >4 and ≤7 cm group (5.08 vs. 4.38 cm, P < 0.0001), except for >7 cm (8.9 vs. 8.0 cm, P = 0.142). Among patients with clear cell RCC, the mean RTS was larger than the mean PTS (4.57 vs. 3.98 cm, P = 0.004), similar result was also seen in non-clear cell group (4.54 vs. 4.16 cm, P = 0.045). The mean RTS was larger than PTS for the approach of radical nephrectomy (RN) (5.26 vs. 4.64 cm, P = 0.01), but not for the partial nephrectomy (PN) (3.34 vs. 2.92 cm, P = 0.067). Of the 257 renal cancers, 76 tumors were down-staged when comparing radiographic and pathologic tumor maximal diameter. The proportion of down-staged tumors had no difference between different genders (P = 0.283), different surgery approaches (P = 0.102), and different pathology types (P = 0.209). In this study, we found that renal tumor size was overestimated by radiography compared with pathologic results, and the T staging of some tumors was down-staged. But for patients who underwent PN, there was no difference between RTS and PTS. These results suggested that the PN should be considered first for the T1b renal tumor when tumor size was close to 4 cm, while the recommendation level of PN for T1b tumor was grade B according to EAU guidelines. Keywords: Renal cell cancer, Nephrectomy, Tumor size, Radiologic, Pathologic Background Renal cell cancer (RCC) represents 2–3 % of all cancers. The estimated new cases and deaths were 61,560 and 14,080 in US in 2015 (Siegel et al. 2015). Despite the rapid increase for several decades, the incidence rates of RCC stabilized during the year of 2007 and 2011. It may partially attribute to the increasing use of abdominal *Correspondence: ; † Ning Zhang and Yishuo Wu contributed equally to this work and should share first authorship 1 Department of Urology, Huashan Hospital, Fudan University, No. 12 Central Urumchi Road, Shanghai 200040, People’s Republic of China Full list of author information is available at the end of the article imaging test in annual heath examination. In addition, the death rates decreased by 0.9 % per year from 2007 to 2011 (American Cancer Society 2015). Nevertheless, due to the relatively high incidence, RCC had became one of the most important healthcare issues worldwide. For the localised RCC, surgery is the only curative treatment with high-quality evidence. Partial nephrectomy (PN) and radical nephrectomy (RN) are the two major styles of surgical procedures. And the size of a renal tumor is important for staging, prognosis and the selection of the appropriate surgical procedure. For localized tumor, of which the T staging is T1, PN is recommended by guidelines (Motzer et al. 2015; Ljungberg © 2016 The Author(s). This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. Zhang et al. SpringerPlus (2016) 5:899 Page 2 of 4 et al. 2015). The decision of performing PN is normally determined by the radiologic size, but not the pathologic size. The radiologic size of tumor is usually measured by preoperative CT scan (Satasivam et al. 2012). Therefore, it is necessary to investigate the difference between pathologic and radiologic sizes, which would help urologists to make better decisions in clinical practice. Some studies have revealed that there existed a certain degree of discrepancy between the preoperative size of renal tumors as measured by CT and the pathologic size as determined from surgical specimens (Choi et al. 2015; Chen et al. 2013; Lee et al. 2010). Since a discrepancy often exists between the preoperative radiologic tumor size (RTS) and the postoperative pathologic tumor size (PTS), the over-estimated tumor size by CT might cause the upstage of preoperative T stage and lead to the loss of opportunity to receive PN for quite a number of the patients (Kanofsky et al. 2006; Aertsen et al. 2013). Thus we performed this study to evaluate whether the discrepancies between the radiologic and pathologic sizes have an impact on tumor staging and the appropriate choice of surgical procedure. Results In current study, a total of 257 patients were included, among which 181 were men (70.4 %) and 76 were women (29.6 %). The baseline characteristics of the patients were shown in Table 1. The median age was 56.8 years (range 18–86 years) and the median BMI was 24.46 (range 15.63–32.37). Among these subjects, 164 (63.8 %) received RN and 96 (36.2 %) underwent PN. Among all the patients, there were 183 patients (71.2 %) with T1a clinical stage and 57 (22.2 %) with T1b clinical stage. The most common histologic subtype was clear cell (80.9 %). All tumors had no positive margins. The mean RTS were larger than PTS (4.57 ± 2.15 vs. 4.02 ± 2.15 cm, P = 0.004) with a discrepancy of 0.55 cm. In addition, when the RTS was ≤4 cm, the mean RTS (2.90 cm) was still larger than PTS (2.59 cm) (P = 0.002) and such difference also existed when the RTS was 4–7 cm (RTS 5.08 cm vs. PTS 4.38 cm, P < 0.0001). However, when the RTS was > 7 cm, the mean RTS (8.9 cm) and mean PTS (8.0 cm) were not statistically different (P = 0.142) (Table 2). Table 1 Demography Feature Median ± SD or n (%) No. of total subjects 257 Age (years) 56.8 (range 18–86) RTS (cm) PTS (cm) P value Gender Male 181 (70.4 %) Female 76 (29.6 %) BMI 24.46 (range 15.63–32.37) 4.41 ± 1.96 4.93 ± 2.54 3.84 ± 1.85 4.43 ± 2.72 <0.0001 <0.0001 Tumor side Left 117 (45.5 %) Right 140 (54.5 %) 4.46 ± 2.07 3.90 ± 2.04 <0.0001 RN 164 (63.8 %) 93 (36.2 %) 5.26 ± 2.12 4.64 ± 2.21 0.01 PN 2.92 ± 1.54 0.067 4.57 ± 2.09 3.98 ± 2.06 0.004 4.16 (...truncated)