# A ten-year cohort of incidental findings to calibrate follow-up guidelines

Source: https://onco.cc/ideas/idea-prev-incidentaloma-natural-history-cohort/  
OnCo record `idea-prev-incidentaloma-natural-history-cohort` (Idea). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Scans find unexpected lumps in the adrenal, thyroid, pancreas and lung. Nobody knows how many matter. A national cohort following them for ten years would tell us whom to watch.

## Summary

Scans find unexpected lumps in the adrenal, thyroid, pancreas and lung, and nobody knows how many matter, so this idea enrols every incidental finding flagged by structured radiology reporting into a national linked cohort followed for ten years. Incidentaloma guidelines rest on small retrospective series; natural history data is the missing evidence, and structured reporting makes capture feasible. The cohort would estimate cancer risk by lesion type, size and patient factors and allow follow-up recommendations to be pruned where risk is very low. The test is enrolment in a national health system with interim analyses at three and five years. Speculative in maturity, it addresses the bottlenecks Overdiagnosis and false alarms and Weak real-world evidence and registries.

## Fields

- Kind: Idea
- Last checked: 2026-09-08
- Hypothesis: For at least three common incidentaloma categories, ten-year cancer risk is low enough (under 1%) that current follow-up recommendations can be dropped, reducing follow-up imaging by at least 30%.
- Rationale: Natural history data is the missing evidence; structured reporting makes capture feasible.
- Proposed test: Enrol via structured reporting in a national health system; interim analyses at three and five years.
- Maturity: speculative
- Actor: data

## Sources

- Bottleneck evidence (Overdiagnosis and false alarms): Welch & Black, Overdiagnosis in cancer (JNCI 2010): https://doi.org/10.1093/jnci/djq099

## Connected records

- fronts: [Early Detection & Screening](https://onco.cc/fronts/early-detection/), [Imaging](https://onco.cc/fronts/imaging/)
- technologies: [CT (computed tomography)](https://onco.cc/technologies/ct/), [MRI](https://onco.cc/technologies/mri/)
- bottlenecks: [Overdiagnosis and false alarms](https://onco.cc/bottlenecks/b-overdiagnosis/), [Weak real-world evidence and registries](https://onco.cc/bottlenecks/b-real-world-evidence/)
- key papers: [Overdiagnosis in cancer](https://onco.cc/key-papers/paper-welch-j-natl-cancer-inst/)

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