• Too many terms
    There have been many new and expanded terms added to ICD-O-3. Many pathology reports include multiple terms that may either be descriptive or diagnostic. In addition, there are many terms that could describe either a single or multiple tumors.
  • In situ subtypes
    Some ductal subtypes are specific to in situ tumors and have been incorrectly assigned a malignant behavior code. The case has been incorrectly coded to a more specific invasive term even if the specific term describes only the in situ component of a tumor.
  • Invasive subtypes
    Same issue as above: incorrect assignment of a more specific code that does not describe the principal invasive component.
  • In situ and invasive together
    Specific instructions are needed on how and what to code when both in situ and invasive tumors co-exist or are combined within a single tumor.
  • "Recurrence"
    The different definitions of recurrence that registrars and clinicians use is a big issue because it affects how new cancers are counted.
  • nonspecific (NOS—not otherwise specified) versus specific histology
    Most breast cancers are ductal carcinoma of no special type; the issue is when to code something more specific as identified in the pathology report's microscopic description section.
  • Combination histologies
    There are specific codes in ICD-O-3 for coding ductal and lobular carcinoma alone or in combination with each other, but there are no rules about coding combinations of ductal subtypes or lobular subtypes or other complex histologies.
  • Paget disease
    Different codes are available for coding Paget disease with or without invasive ductal or other malignancy of breast, and the behavior code varies for certain Paget disease phrases as well.
  • Lobular and ductal carcinoma
    Historically, ductal and lobular carcinoma are treated as a single primary even if they are in different tumors within a breast. Do the existing rules need a change in priority?
  • Inflammatory carcinoma
    Even though this is primarily a staging issue, guidance is needed in determining whether bilateral inflammatory carcinoma is one or multiple primaries, as well as the correct coding of histology for these cases.