Growth Rate Sensitivity Explorer

Hold a cross-sectional tumor-size distribution fixed and watch the implied natural-history timescale swing wildly as the assumed growth rate changes.

  • sensitivity analysis
  • natural history
  • tumor growth
  • assumption dependence

Implied years from initial lesion to observed size

Median = 4.7 yr051015202530010203040506070Implied yearsNumber of tumors

Growth trajectory with observed tumor volumes

05101520253002004006008001000Years from initial lesionVolume (cm³)

Summary statistics

StatisticValue
Tumors (n)298.000
Median implied years4.701
IQR (years)2.9–7.1
Assumed growth rate0.40 cm/yr
Initial diameter1.0 cm
The data didn't change — only the assumption did
Every histogram above is generated from the same fixed cross-sectional tumor sizes. Sliding the assumed growth rate from 0.2 to 1.0 cm/year moves the median implied age of these tumors by more than a decade. Reporting a natural-history timescale from cross-sectional imaging without stating (and justifying) the growth-rate assumption is a hidden modeling choice dressed up as a measurement.