Seems to be a system used to classify the stage of the disease.

Does it make sense with the rest of the text?

To be precise, it means:
Coeff times the value of key letters
In the French fee-for-service system, the fee schedule, or relative value scale, is known as the Nomenclature Generale des Actes Professionnels3. Originally written by the CSMF in 1930, it classifies medical procedures by so-called key letters. For example, C signifies a consultation with a general practitioner; B signifies laboratory tests; Z signifies all radiological procedures; and K signifies surgical and specialty procedures. The Bs, Zs, and Ks are always followed by a coefficient that is supposed to reflect their relative value on an elaborate scale of medical procedures. For example, an appendectomy or simple hernia operation is coded as K-50, whereas the surgical removal of an ingrown toenail is coded as K-10. Physician fees are equal to the coefficient times the value of the key letters that serve as the explicit object of bargaining during the national fee negotiations.
http://www.nyu.edu/projects/rodwin/marriage.html
http://content.healthaffairs.org/content/12/3/111.full.pdf
http://www.ehma.org/files/Benefit_Report_France.pdf