What rounding rule is applied when measuring tumors between 1-4 mm?

The rounding rule applied when measuring tumors between 1-4 mm is to round down. This is in accordance with standard practices in oncology measurements which dictate that smaller tumor sizes, particularly in the range of 1-4 mm, are typically rounded down to ensure consistency and accuracy in reporting and treatment decisions.

Rounding down helps avoid overestimation of tumor size, which can have implications for staging and subsequently impact treatment planning. For instance, if a tumor is measured at 4 mm, rounding down to the nearest whole number (which is 3 mm) may be more beneficial in certain scenarios to avoid aggressive treatments that might be indicated for larger tumors.

This practice balances the need for precision in measurement with the realities of clinical decision-making, where even small discrepancies in size can influence the overall assessment of cancer staging, prognosis, and potential treatment options.