Parameters:
(1) maximum diameter of the tumor in cm (size of the invasive component)
(2) estrogen and progesterone receptor status
(3) histologic and/or nuclear grade
(4) age of the patient in years
Criteria for minimal/low risk - all of the following:
(1) size of the invasive component <= 1.0 cm
(2) estrogen and/or progesterone receptor positive
(3) Grade 1 (relevance uncertain)
(4) age >= 35 years
Some participants would also include absence of definite lymphatic and/or vascular invasion.
Criteria for high risk - any of the following:
(1) size of the invasive component > 2.0 cm
(2) estrogen and progesterone receptor negative
(3) Grade 2-3
(4) age < 35 years
Intermediate risk was any case that did not meet criteria for low or high risk.
Limitations:
• The reporting of histologic grade is ambiguous. Table 2 shows intermediate risk for Grades 1-2 and high risk for Grades 2-3. For the implementation I will use 5 histologic levels (Grade 1, Grade 1-2, Grade 2, Grade 2-3, and Grade 3) with addition of the low-to-intermediate and intermediate-to-high categories.
• I find classifying an estrogen receptor negative, progesterone receptor positive tumor as minimal/low risk a bit confusing.
