The next section of the General Instructions provides brief definitions of a number of words used in the rules. These are:
- Clinical Diagnosis
- Contiguous tumor
- Most representative specimen
- Multiple primaries
- Overlapping tumor
- Paired organ/site
- Single primary
Read and understand these definitions, as they apply to all sets of rules. Two word groups merit special attention at this point; the rest should be reviewed when the registrar encounters them.
Focal - Foci - Focus
Unlike the equivalent terms listed in the previous section, these words are not interchangeable.
- Focal means limited to one specific area and may be either microscopic (seen through a microscope) or macroscopic (seen with the naked eye). Focal is an adjective and is not a synonym for focus.
- Focus is a pathologic term describing cells that can be seen only microscopically. The cells stand out from surrounding tissue based on their appearance, special stains, or other testing.
- Foci is the plural of focus and implies only microscopic visualization of the tumor cells.
The subtle differences in the definitions of these words affect how multiple tumors are counted.
In the previous multiple primaries rules, there was a problem with coding a case stated as a 'recurrence'. Any time the word 'recurrence' was mentioned—in the physician's or consultant's notes, history or summary, the registrar would automatically code the case as a recurrence. In other words, the registrar would not abstract a subsequent primary, even if the new tumor was 20 years later or in a contralateral organ. However, the term 'recurrence' has two meanings.
- The appearance of a disease that was thought to be cured or inactive or in remission.
Recurrent cancer starts from cancer cells that were not removed or destroyed by the original therapy.
By this we are saying that the patient had cancer and all of a sudden there is a recurrence of that disease caused by the same cells as the original disease.
- A new occurrence of cancer arising from cells that have nothing to do with the earlier (or first) cancer.
This is 'recurrence' used in a general sense; it can be a new incidence, episode or report of the same disease, not necessarily from the original cells. For example, a patient had breast cancer in the right breast and years later she has breast cancer in the left breast. A physician may say the patient has a recurrence of breast cancer, which she does. The physician is talking about the fact that the patient once had breast cancer and she now has breast cancer again. The physician is not saying that the second breast cancer is caused by the first breast cancer cells.
The use of the term 'recurrence' had some inherent problems. The physicians on the MPH Task Force agreed that they used the word to mean both of these types of recurrence and they had never really known that we were coding literally and making casefinding decisions based on the word.
The new rules say:
- Do not use a physician's statement to decide whether the patient has a recurrence of a previous cancer or a new primary.
- Use the multiple primary rules as written unless a pathologist compares the present tumor to the 'original' tumor and states that this tumor is a recurrence of the previous primary.
The 2007 MPH rules take the guesswork out of trying to interpret what a physician means when he/she uses the term. The new rule will be used to determine whether the patient indeed has a recurrent tumor or a new primary. This is a big change for many registrars who follow Commission on Cancer rules as stated in the Facility Oncology Registry Data Standards (FORDS) manual.
This new rule has been established in consultation with Commission on Cancer representatives and National Program of Cancer Registries representatives on the MPH Task Force. It has also been established with the acknowledgement and approval of numerous physicians and physician groups (including CoC and American Joint Committee on Cancer site task forces), who agree this has presented a significant problem to registrars for many years and that removing the subjectivity of the clinician's use of the term is a better way to handle differentiating between true recurrences and new primaries.