Josh R. Waldman

Josh R. Waldman asked for expectations regarding TissueCypher volume growth in 2026, specifically whether it would come more from existing ordering base penetration or new clinicians, and the current clinician penetration level. Josh R. Waldman also inquired about expected quarter-over-quarter declines for DecisionDx-Melanoma volumes in Q1 and the cadence of year-over-year volume growth throughout 2026, given tougher comps in the back half.

Answer

Frank Stokes, Chief Financial Officer of Castle Biosciences, stated that over 2,000 new ordering clinicians were added in 2025, bringing the total to approximately 3,000 out of 12,000-14,000 targetable GI clinicians, representing 25-30% HCP penetration. Patient penetration is around 11%. He expects continued strong volume growth in 2026, though percentage growth might be lower due to larger numbers and reaching later adopters. Frank Stokes described predictable seasonality for DecisionDx-Melanoma, with flattish sequential growth each quarter except for a step-up from Q1 to Q2. This pattern is driven by physician-patient encounters, with Q1 typically seeing reduced encounters due to large dermatology meetings. He expects similar flattish performance from Q4 to Q1.

Josh R. Waldman asked for expectations regarding TissueCypher volume growth in 2026, specifically whether it would come more from existing ordering base penetration or new clinicians, and the current clinician penetration level. Josh R. Waldman also inquired about expected quarter-over-quarter declines for DecisionDx-Melanoma volumes in Q1 and the cadence of year-over-year volume growth throughout 2026, given tougher comps in the back half.

Answer

Frank Stokes, Chief Financial Officer of Castle Biosciences, stated that over 2,000 new ordering clinicians were added in 2025, bringing the total to approximately 3,000 out of 12,000-14,000 targetable GI clinicians, representing 25-30% HCP penetration. Patient penetration is around 11%. He expects continued strong volume growth in 2026, though percentage growth might be lower due to larger numbers and reaching later adopters. Frank Stokes described predictable seasonality for DecisionDx-Melanoma, with flattish sequential growth each quarter except for a step-up from Q1 to Q2. This pattern is driven by physician-patient encounters, with Q1 typically seeing reduced encounters due to large dermatology meetings. He expects similar flattish performance from Q4 to Q1.