Cancer Tumor Growth Rates Vary by Genetic Subtype

Researchers have found that tumor growth rates vary clinically and statistically based on genetic subtype, and support the use of frequent or extended surveillance for different situations (J Clin Oncol. 2020 Feb 21. Epub ahead of print).

“Published series of growth rates of renal tumors on active surveillance largely consist of tumors without pathologic or genetic data. Growth kinetics of genetically defined renal tumors are not well known,” explained Mark W. Ball, MD, Assistant Research Physician, Urologic Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, and co-investigators.

Through a study of 292 patients with kidney cancer susceptibility syndrome inherited via a pathologic germline alteration of VHL, MET, FLCN, or BAP1, Dr Ball et al assessed the relationship between genetically defined renal tumors and clinical and genetic patient characteristics.

All patients had at least 1 solid renal mass being actively monitored. Investigators calculated tumor growth rates (GR), stratified patients based on genetic alteration and other clinical and genetic factors, and used linear regression and comparative statistics to evaluate differences in growth rates used linear regression and comparative statistics.

Ultimately, Dr Ball and colleagues located 435 genetically defined tumors, including 286 VHL-deficient, 91 FLCN-deficient, 52 MET-activated, and 6 BAP1-deficient tumors. When stratified by genetic alteration, tumors yielded significantly different GRs.

Specifically, BAP1-deficient tumors had the fastest median GR (0.6 cm annually; interquartile range [IQR], 0.57-0.68 cm annually), tailed by VHL-deficient tumors (GR, 0.37 cm annually; IQR, 0.25-0.57 cm annually), FLCN-deficient tumors (GR, 0.10 cm annually; IQR, 0.04-0.24 cm annually), and tumors with MET activation (GR, 0.15 cm annually; IQR, 0.053-0.32 cm annually; P <.001).

Of note, tumors from the same patient were found to have similar GRs, and an independent association was observed between younger age and higher GR (P = .005).

“In a cohort of genetically defined tumors, tumor growth rates varied in a clinically and statistically different manner according to genetic subtype. Rapid growth of BAP1-deficient tumors indicates that these patients should be managed with caution,” reported Dr Ball and co-investigators.

“The faster growth of tumors in younger patients may support more frequent imaging, whereas the slower growth of other tumors may support extended surveillance beyond annual imaging in some instances,” they concluded.—Hina Porcelli