Dukes classification

The Dukes classification (alternatively Dukes' classification) is a staging system for colorectal cancer that ranges from A through to D.

A: Invasion into but not through the bowel wall

B: Invasion through the bowel wall but not involving lymph nodes

C: Involvement of lymph nodes

D: Widespread metastases

It can also be separated again (though this is not always used):

A: Limited to mucosa

B1: Extending into muscularis propria but not penetrating through it; nodes not involved

B2: Penetrating through muscularis propria; nodes not involved

C1: Extending into muscularis propria but not penetrating through it. Nodes involved

C2: Penetrating through muscularis propria. Nodes involved

D: Distant metastatic spread

The classification system is named after its inventor Cuthbert Dukes in 1932. According to Who Named It, the staging system should correctly be described as Dukes' classification but Wikipedia and others describe it as Dukes classification (minus the apostrophe). Wikipedia, however, agree with Who Named It in terms of the spelling of Dukes' Disease, named after Clement Dukes, in which they use the apostrophe.

There is debate as to whether it should be Dukes A, Dukes' A or even Dukes's A (as correct grammar rules state that there should be an apostrophe then an s even for people whose last name ends in s) and all 3 are widely used. A 4th variation, Duke's A (etc) is also widely used, although this 4th variation is definitely incorrect, as it is named after someone called Dukes, not Duke.

In eponyms such as this (diseases etc named after people) there is inconsistency in terms of whether or not they have an apostrophe or not. For example, Albert Einstein's theory of relativity is described with an apostrophe but his refrigerator is simply known as The Einstein Refrigerator, without an apostrophe and his theory about worm holes is known as The Einstein-Rosen bridge, not Einstein's and Rosen's bridge.

There does not appear to be any absolute certainty as to which method of spelling is correct, with or without the apostrophe, and it seems to get down to an individual choice. There are roughly as many cases (and with as much authority) saying Dukes A as there are saying Dukes' A, as these two seem to be the main alternatives in use.

While Wikipedia isn't necessarily wrong, their refusal to include an alternative makes them incompletely accurate.