The Significance of the “KGS Practice” in Pathology and Oncology Part 9
PART 9: Application of the “KGS Scoring”
APPLICATION of the KGS SCORING
The parametric KGS Scoring is worked out, as below, by summing up the calculated KGS scores of the five parametric data groups, PTC (Prime Tumor Cells), MTC (Mitotic Tumor Cells), CTC (Circulating Tumor Cells), NTC (Necrotic Tumor Cells) and MET (metastases), and thereby determining the KGS Index which is the critically important prognostic guiding element of the KGS grading.
Low Grade (Benign and Pre-neoplastic) Tumors
Grade III: In Grade III tumor tissues, the only KGS parameters to put into account for the KGS scoring are the PTC (Primary Tumor cells) [with a KGS Impact Factor (IF) of 0.3] and the MTC (Mitotic Tumor Cells) [with a KGS Impact Factor (IF) of 2.0]. The other three parameters, CTC (Circulating Tumor Cells), NTC (Necrotic Tumor Cells) and MET (metastases), are not applicable. So, a Grade III tumor’s KGS Index is the total of the parametric PTC and MTC scores.
PTC: Standard scoring [KGS Impact Factor (IF): 0.3]
MTC: Standard scoring [IF: 2.0]
CTC: N/A
NTC: N/A
MET: N/A
Grade IV-V: Just as in Grade III tumors, the only KGS parameters to put into account for the KGS scoring in Grade IV and Grade V tumors are the PTC and MTC (with a 1.0 IF for PTC and a 2.0 IF for MTC). The other KGS parameters (CTC, NTC and MET) are not applicable (N/A).
PTC: Standard scoring [IF: 1.0]
MTC: Standard scoring [IF: 2.0]
CTC: N/A
NTC: N/A
MET: N/A
High Grade (Malignant) Tumors
Grade VI–VII: The high-grade (Grade VI–VII) prime tumor cell (PTC), the chief prognostic indicator for malignancy, is the most essential scoring parameter in the KGS’s solid tumor grading.
With a KGS Impact factor (IF) of 1.0, prime tumor cells (PTCs) are basically the undifferentiated high-grade (Grade VI-VII) cells of the tumor which has histopatholologically been examined, graded and scored in the KGS Pathology Report routinely.
The PTC Score in a primary tumor is based on the total Grade VII (Grade VIIA +Grade VIIB) and/or Grade VI (Grade VIA + Grade VIB) cells’ mean percentage in 10 HPF (High-Power Field)-supported LPFs (Low-Power Fields) from the periphery of the examined tissue.
PTCs are not necessarily always the cells of a primary tumor. In tumors of “Unknown Primary Origin” (Cancers of Unknown Primary Origin-CUP), the examined PTCs come from the metastases, and in cases of removed tumors followed by emerging metastases, the successive PTC scores are based on the cells of the metastases.
The calculation of PTCs’ parametric score varies depending on the examined tumor’s status and features:
After the removal of the Primary Non-metastatic Tumor: Although there is no longer a tissue to examine after a tumor’s excision, the tumor’s previously recorded parametric status remains to be in effect holding the pre-excision scores of the three of the recorded parameters, the PTC, MTC and NTC. The CTC and MET meanwhile are followed with quarterly follow-ups for one year.
PTC: Latest (pre-excision) score remains.
MTC: Latest (pre-excision) score remains.
CTC: Quarterly follow-up for one year.
NTC: Latest (pre-excision) score remains.
MET: Quarterly follow-up for one year.
After the removal of the Primary Non-Metastatic Tumor Followed byMetastasis: After the removal of a primary tumor followed by metastasis, the metastatic tissue gets examined histopathologically taking the status for the PTC scoring. In a case of multiple metastases, anatomically the nearest (to the primary tumor site) or the largest metastasis gets examined for the KGS Pathology Report; under the standard/expected circumstances, the case is automatically given 10 PTC score (PTC Score = 10) since the examined tissue of the metastasis would consist of 100% high-grade (Grade VI / Grade VII) tumor cells. For the MET scoring, metastatic counting is done with the usual KGS method with the inclusion of the examined metastasis.
PTC = 10
MTC: Standard scoring.
CTC: Standard scoring.
NTC: Standard scoring.
MET: Standard scoring.
Regressing Primary Tumor: In its histopathological examination, a regressing tumor gets PTC-scored standardly (as done in its active stage).
PTC: Standard scoring.
MTC: Standard scoring.
CTC: Standard scoring.
NTC: Standard scoring.
MET: Standard scoring.
Regressed Primary Tumor: In the histopathological examination of a totally regressed tumor, the PTC Score is marked as nil (PTC Score = 0) since the percentage of the total tumor cells is nil or almost nil.
PTC = 0
MTC: NLA (no longer applicable)
CTC: NLA
NTC: NLA
MET: NLA
Recurrent Tumor: A recurrent tumor is PTC-scored same as the primary tumor of the same case.
PTC: Standard scoring.
MTC: Standard scoring.
CTC: Standard scoring.
NTC: Standard scoring.
MET: Standard scoring.
Tumor of Unknown Primary Origin (Cancer of Unknown Primary Origin-CUP)
In a tumor of unknown primary origin, a detected tumor, a sole metastasis, or the largest of the detected multiple metastases, is histopathologically examined and scored like a primary tumor; while the PTC parameter automatically gives a 10-point score (PTC Score = 10), since the tissue consists of Grade VII cells, the other four parameters are worked out with standard scoring. Such tumors’ parametric MET scoring is calculated and added to the KGS Index in the routine way as they are all metastases and are taken into account as such.
PTC = 10
MTC: Standard scoring.
CTC: Standard scoring.
NTC: Standard scoring.
MET: Standard scoring.
Primary Tumor unreachable and inoperable due to Anatomic Location
- With a possibility of biopsy, a malignant tumor inoperable due to location, is examined and evaluated for the PTC scoring in the standard way of examining primary tumors.
PTC: Standard scoring.
MTC: Standard scoring.
CTC: Standard scoring.
NTC: Standard scoring.
MET: Standard scoring.
- KGS Safety Score: With no possibility of biopsy, any tumor, benign or malignant, inoperable due to anatomic location is automatically given an upfront score of 15; this is called Safety Score, and consists of 10 points for the PTC scoring and 5 points for the MTC scoring. To practically keep on the safe side, this entitlement of automatic scoring is critically useful and crucially necessary in clinical management.
KGS Safety Profile: Being in the medium (M) KGS Prognostic Range (Table 4), a tumor with a KGS Safety Score possesses a KGS Safety Profile which is a special profile degree given to a primary tumor that is both unreachable and inoperable due to anatomic location.
PTC = 10
MTC = 5
CTC: Standard scoring.
NTC: N/A
MET: Standard scoring.
