Distribution of renal tumor growth rates determined by using serial volumetric CT measurements.
OBJECTIVE
To retrospectively determine the distribution of growth rates across different sizes and subtypes of renal cortical tumors by assessing tumor volume and maximum tumor diameter at serial volumetric computed tomographic (CT) examinations.


METHODS
The institutional review board approved this retrospective, HIPAA-compliant study. Fifty-three of 2304 patients (34 men, 19 women; mean age, 67 years +/- 10 [standard deviation; range, 39-88 years) who underwent nephrectomy from 1989 to 2006 did not receive preoperative chemotherapy or radiation therapy and underwent at least two preoperative contrast material-enhanced CT examinations (at least 3 months apart) with identical section thickness that was no more than one-fifth of longitudinal tumor diameter. Tumor volume and maximum diameter were measured on CT scans. Reciprocal of doubling time (DT) (RDT) was calculated. Analysis of variance and Student t tests were performed.


RESULTS
Thirty-two clear cell carcinomas, 10 papillary carcinomas, six chromophobe carcinomas, four oncocytomas, and one angiomyolipoma were analyzed. Median tumor size was 2.9 cm (range, 1-12 cm). Seven tumors did not increase in volume. DT ranged from -78476.54 to 18057.43 days (mean, -1230.73 days; median, 590.51 days). [corrected] Growth rate determined by using maximum diameter ranged from -10.8 to 33.2 mm/y (mean, 5.1 mm/y; median, 3.5 mm/y). Faster-growing tumors were more likely to be clear cell carcinomas, those of higher grade had higher growth rates. No significant correlation was found between RDT and tumor initial volume, subtype, or grade. Small renal tumors (<or=3.5 cm) were similar to larger tumors in subtype and growth rate. Age at diagnosis correlated negatively with renal tumor growth rate (P = .03).


CONCLUSIONS
Growth rates in renal tumors of different sizes, subtypes, and grades represent a wide range and overlap substantially. Small renal tumors appear to be similar to larger ones in nature.
Zhang
Jingbo
J
Department of Radiology, Memorial Sloan-Kettering Cancer Center, 1275 York Ave, New York, NY 10021, USA. zhangj12@mskcc.org
Kang
Stella K
SK
Wang
Liang
L
Touijer
Abdelkarim
A
Hricak
Hedvig
H
D018249:Adenoma, Oxyphilic / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018207:Angiomyolipoma / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D002291:Carcinoma, Papillary / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D002292:Carcinoma, Renal Cell / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D054893:Cone-Beam Computed Tomography / Q000379:methods*; D018450:Disease Progression; D005260:Female; D006801:Humans; D007672:Kidney Cortex / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D007680:Kidney Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D008297:Male; D008432:Mathematical Computing; D008875:Middle Aged; D009367:Neoplasm Staging; D011379:Prognosis; D012189:Retrospective Studies; D047368:Tumor Burden