The changes that come about with cases diagnosed on and after January 1, 2007 are important. First and foremost, the 2007 multiple primary rules replace all previous multiple primary rules—even the ones that you remember as "so-and-so told me in 1988 that this is how you code cases like this". The key word is diagnosed. Cases diagnosed prior to 2007 are counted and coded according to the rules that were in effect at the time the case was diagnosed, even if they are accessioned by your registry in 2007 or later. So keep the old rules in an archive file—do not discard those "retired" manuals, because you may need to refer to them for straggler cases or non-analytic cases that are identified in 2007 or later.
The 2007 rules come complete with their own set of word lists, definitions, equivalent terms, ambiguous terms, and site-specific rules and priorities. They are self-contained. That means that you do not borrow rules, word lists, definitions, and so forth from other registry activities, such as staging and grading of tumors. Conversely, you do not borrow rules, word lists, and definitions from the 2007 rules for other registry purposes. In particular, do not use the 2007 Multiple Primaries and Histology (MPH) Coding rules to determine case reportability. The 2007 MPH rules take effect after you have determined that a case is reportable according to the rules that have been in effect for years.
Experienced registrars will have to "unlearn" or forget the previous rules because many things have changed for 2007 cases.
Changes in Multiple Primaries Rules
- In the former multiple primaries rules, registrars had to remember that certain primary sites were grouped together in the ICD-O first edition and still had to be grouped together in the second and third editions. Those rules no longer apply; the previous list of grouped sites (Table 24 in ICD-O-3) is obsolete as of January 1, 2007 diagnoses. Each set of site-specific rules lists what sites are grouped for that set of rules. For example, kidney has been "ungrouped" from renal pelvis and ureter (all were code 189._ in ICD-O-1). Kidney—primarily a glandular organ—now has its own site-specific rules; renal pelvis and ureter are now grouped with bladder and urethra, all of which produce urothelial tumors that have a different set of site-specific rules.
- In the former multiple primaries rules, most primary sites were defined as "different" or "separate" primaries at the three-character level. In other words, a breast primary (C50._) is different from a lung primary (C34._) or stomach primary (C16._), and a lip primary (C00._) is different from a tongue primary (C01._ or C02.). Certain other sites were defined as separate primaries at the decimal level, including the segments of the colon and the ICD-O-3 skin sites. In the 2007 rules, a few more three-digit codes in the head and neck sites are defined as separate primaries: upper lip (C00.0, C00.3) and lower lip (C00.1, C00.4), upper gum (C03.0) and lower gum (C03.1), and nasal cavity (C30.0) and middle ear (C30.1).
- In the former multiple primaries rules, the same tumor appearing in the same site again after two months was considered a new primary. In the 2007 rules, the length of time between the two diagnoses will vary on a site-specific basis from 60 days (formerly two months) to as much as five years.
- Furthermore, registrars will not use a clinician's reference to "recurrence" to decide whether a case is a new primary or not. All of the rules about tumor site, histology, time between diagnoses and other aspects of the rules will be applied, but a reference to recurrent cancer is to be disregarded unless a pathologist actually compares the slides from the original or first cancer to the current cancer and states somewhere in the pathology report that the new tumor is a reappearance of the previous cancer.
Changes in Histology Coding Rules
Three important changes in the histology coding rules will be implemented for cases diagnosed on and after January 1, 2007.
- Histology will be coded from the final diagnosis only. That's the ultimate message the pathologist wants to convey to the clinician about the tumor. No longer will registrars get bogged down scanning the microscopic narrative for descriptive terms that may or may not be codable.
There will be prioritized guidelines to determine whether the terminology of the final diagnosis represents a more specific histology. Terms like type, subtype, with ____ differentiation and others will point toward more specific histology, as they have done in the past, but priorities have been set for when these terms apply.
- For tumors where both invasive and in situ components are present, we will code the histology of the invasive cell type, even if it is less specific. After all, it is the invasive part of the tumor that has the potential to kill the patient. That's what the clinician pays attention to when deciding treatment, so that's what should be recorded on the abstract.
- There will also be site-specific priorities and rules for coding complex and combination histology codes, such as comedocarcinoma when mixed with other types of ductal carcinoma. Some of the site-specific rules will provide tables to determine the proper mix of cell types that can be coded to a complex histology like 8255 Adenocarcinoma with mixed subtypes versus 8323 Mixed cell adenocarcinoma. Other sets of rules will provide charts to display the relationships between less specific and more specific codes. For example, a chart provided for lung shows that large cell carcinoma, NOS is actually a more specific code than sarcomatoid carcinoma.
- A list of ambiguous terminology is provided for use when for assigning the histology code. The list is fairly limited:
- Comparable with
- Compatible with
- Consistent with
- Most likely
- Suspicious (for)
- Typical (of)
There is no list of terms that do not apply, because registrars were confused by having an ambiguous terms list and then another list that said "Do not code these as ambiguous terms". When they encountered a term that was not on either list, they really weren't sure what to do with it. So in the new rules there is only one ambiguous terms list to use. Anything that is not on this list should not be used for assigning the histology code.
OK, you're thinking, how am I supposed to remember all these changes? The answer is, you're not. Do not attempt to memorize the rules&you&ll only get yourself confused between old rules and new rules and between different sets of site-specific rules. Instead, refer to the multiple primaries and histology coding rules each and every time you encounter a case where the new rules are needed. So your next question is probably going to be how often are the new rules needed?