Background
Methods
Definition
Identification of potential and final factors of variability
Area of variability
Area (Source of information) | Final factors of variability included | Methods of calculation |
---|---|---|
Area 1 | Number of: surgical biopsies, micro-biopsies, needle | Sum of the factors per patient |
Q. biopsies (A) | aspiration cytology | Calculation of the mean per object |
Area 2 | Number of: days for inpatient; days for outpatient | Sum of the factors per patient |
Q. hospital admissions (A) | Calculation of the mean per object | |
Area 3 | Number of: chest radiograph, colonoscopy, computed tomography, ultrasound, magnetic resonance imaging | Sum of the factors per patient |
Q. imaging (A) | Calculation of the mean per object | |
Area 4 | Number of external consultations | Calculation of the mean per object |
Q. external consultations (A) | ||
Area 5 | Number of: Ps packs, red blood cell packs | Sum of the factors per patient |
Q. transfusions (A) | Calculation of the mean per object | |
Area 6 | Number of radiotherapy sessions | Calculation of the mean per object |
Q. radiotherapy (A) | ||
Area 7 | Number of preparations for radiotherapy sessions | Calculation of the mean per object |
Q. preparation for radiotherapy (A) | ||
Area 8 | Drug administration (yes/no): Caelyx, Carboplatin, Cisplatin, Deticene, Doxorubicin, Etoposide, Gemcitabin, Holoxan, Ifosfamide, Imatinib, Melphalan, Vinorelbin, Oxaliplatin, Paclitaxel, Vincristine | Sum of the “yes” for the fifteen factors per patient. |
Q. chemotherapy drugs (A) | ||
Calculation of the mean per object | ||
Area 9 | Unit cost of: surgical biopsies; microbiopsies; needle | Calculation of the mean cost of the factors by country. |
C. biopsies (B, C) | aspiration cytology | Application of the mean (by country) to the objects with quantity of biopsies >0 |
Area 10 | Unit cost of: days for inpatient, days for outpatient | Calculation of the mean of the factors by country. |
C. hospital admissions (D) | Application of the mean (by country) to the objects with quantity of days of hospital admissions >0 | |
Area 11 | Unit cost of: chest radiograph; colonoscopy; computed tomography; ultrasound; magnetic resonance imaging | Calculation of the mean of the factors by country. |
Application of the mean (by country) to the objects with quantity of imaging >0 | ||
C. imaging (B, C) | ||
Area 12 | Unit cost of external consultations | Application (distinguishing the country) to the objects with quantity of external consultations >0 |
C. external consultations (B,C) | ||
Area 13 | Unit cost of: Ps packs, red blood cell packs | Calculation of the mean of the factors by country. |
C. transfusions (E,C) | Application of the mean (by country) to the objects with quantity of transfusion packs >0 | |
Area 14 | Unit cost of radiotherapy sessions | Application (distinguishing the country) to the objects with quantity of radiotherapy sessions >0 |
C. radiotherapy (B,C) | ||
Area 15 | Unit cost of preparation for radiotherapy sessions | Application (by country) to the objects with quantity of preparation for radiotherapy sessions >0 |
C. Preparation for radiotherapy (B,C) | ||
Area 16 | Unit cost of: Caelix; Carboplatin; Cisplatin; Deticene; Doxorubicin; Etopophos etoposide; Gemcitabine; Holoxan; Ifosfamide; Imatinib; Melphalan; Navelbine; Oxaliplatin; Paclitaxel; Vincristine | Calculation of the mean of the factors by country. |
C. Chemotherapy drugs (F) | Application of the mean (by country) to the objects with quantity of chemotherapy drugs >0 |
Object
Statistical analysis
Cluster analysis
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Single linkage: minimum distance criteria, using the smallest distance between objects in the two groups:
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Complete linkage: maximum distance criteria, using the largest distance between objects in the two groups:
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Average linkage: using the average distance between all pairs of objects in cluster r and cluster s:
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Centroid linkage: using the distance between the centroids of the two groups:
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Ward linkage: using the incremental sum of squares (i.e. the increase in the total within-group sum of squares as a result of joining groups r and s). It is given by:
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RSQ: RSQ measures the heterogeneity of the cluster solution formed at a given step. A large value represents that the clusters obtained at a given step are quite heterogeneous, whereas a small value signifies that the clusters formed at a given step are not very different from each other. It is therefore recommended to have a cluster solution with a high RSQ.
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SPRSQ: The SPRSQ measures the loss of homogeneity due to the merging of two clusters to form a new cluster at a given step. If the value is small, then it suggests that the cluster solution obtained at a given step is formed by merging two very homogeneous clusters. On the other hand, large values of SPRSQ suggest that two heterogeneous clusters have been merged to form the new cluster. In general, a cluster solution with a low SPRSQ is preferred, as a high value for SPRSQ implies that two heterogeneous clusters are being merged.
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RMSSTD: The RMSSTD measures the homogeneity of the cluster formed at any given step. It essentially measures the compactness or homogeneity of a cluster. Clusters in which consumers are very close to the centroid are compact clusters. The smaller the RMSSTD, the more homogeneous or compact the cluster formed is at a given step. A large RMSSTD value suggests that the cluster obtained at a given step is not homogeneous, and is probably formed by the merging of two heterogeneous clusters.
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pF: The pF is intended to capture the tightness of clusters, and is a ratio of the mean sum of squares between groups to the mean sum of squares within groups. It makes it possible to compare the homogeneity of a partition in k classes with that of a partition in (k-1) classes. A “strong” pF value at the level s will indicate a suitable partition in s classes correct. Peaks on the curve give the values of pF according to the number of classes.
Principal component analysis
Hierarchical clustering on principal component
Results
Phases of treatment | All patients (n = 219) | Rhône-Alpes France (n = 58) | Veneto Italy (n = 161) |
---|---|---|---|
Diagnosis | 3,701 (7420) | 1,392 (1,450) | 4,534 (8,484) |
Surgery (primary and wide surgical excision) | 8,170 (7,364) | 9,046 (6,226) | 7,855 (7,749) |
Chemo-therapy | 6,107 (11,988) | 9,689 (14,003) | 4,815 (11,196) |
Radio-therapy | 2,270 (5,850) | 1,615 (2,495) | 2,505 (6,665) |
Follow-up | 5,048 (11,760) | 4,414 (8,864) | 5,277 (12,693) |
Follow-up without relapse | 1,468 (11,760)a
| 1,732 (1,728)b
| 1,379 (2,501)c
|
Follow-up with relapse | 16,261 (11,760)d
| 11,454 (14,745)e
| 18,339 (21,611)f
|
Overall management | 25,296 (22,919) | 26,156 (18,190) | 24,986 (24,575) |
Objects | Areas of variability | |||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Area 1 Q. Biopsies | Area 2 Q. days hospitalization | Area 3 Q. imaging | Area 4 Q. external consultations | Area 5 Q. transfusions | Area 6 Q. rad. sessions | Area 7 Q. rad. preparation | Area 8 Q. chemotherapy drugs | Area 9 C. biopsy | Area 10 C. day hospitalization | Area 11 C. imaging | Area 12 C. external consultation | Area 13 C. transfusion | Area 14 C. rad. session | Area 15 C. rad. preparation | Area 16 C. chemotherapy drugs | |
1. Diagnosis France | 1.34 | 1.29 | 3.66 | 0.76 | 0 | 0 | 0 | 0 | 59.5 | 918.3 | 76.34 | 90 | 0 | 0 | 0 | 0 |
2. Diagnosis Italy | 2.04 | 5.4 | 4.61 | 1.19 | 0 | 0 | 0 | 0 | 41.63 | 602 | 76.24 | 47.45 | 0 | 0 | 0 | 0 |
3. Surgery France | 0 | 13.38 | 1.98 | 0 | 0.8 | 0 | 0 | 0 | 0 | 918.3 | 75.59 | 0 | 199.6 | 0 | 0 | 0 |
4. Surgery Italy | 0 | 10.53 | 2.37 | 0 | 1.72 | 0 | 0 | 0 | 0 | 602 | 76.24 | 0 | 26.3 | 0 | 0 | 0 |
5. Chemotherapy France | 0 | 20.54 | 5.29 | 0 | 2.92 | 0 | 0 | 2.88 | 0 | 918.3 | 98.75 | 0 | 199.6 | 0 | 0 | 2.22 |
6. Chemotherapy Italy | 0 | 18.36 | 8.06 | 0 | 1.52 | 0 | 0 | 2.03 | 0 | 602 | 67.16 | 0 | 26.3 | 0 | 0 | 2.98 |
7. Radiotherapy France | 0 | 1.08 | 0 | 0 | 0 | 26.44 | 1 | 0 | 0 | 918.3 | 0 | 0 | 0 | 137 | 439 | 0 |
8. Radiotherapy Italy | 0 | 11 | 0 | 0 | 0 | 19.87 | 1 | 0 | 0 | 602 | 0 | 0 | 0 | 150 | 871.8 | 0 |
9. Follow-up without relapse France | 0 | 0.38 | 3.28 | 3.41 | 0 | 0 | 0 | 0.05 | 0 | 918.3 | 66.69 | 90 | 0 | 0 | 0 | 0.04 |
10. Follow-up without relapse Italy | 0 | 1.01 | 5.29 | 4.01 | 0 | 0.02 | 0.01 | 0 | 0 | 602 | 76.24 | 47.45 | 0 | 150 | 871.8 | 0 |
11. Follow-up with relapse France | 0 | 7.47 | 2.53 | 5.18 | 0 | 2.47 | 0.13 | 1.53 | 0 | 918.3 | 75.59 | 90 | 0 | 137 | 439 | 3.49 |
12. Follow-up with relapse Italy | 0 | 20 | 11.41 | 5.06 | 0 | 0.26 | 0.04 | 0.47 | 0 | 602 | 76.24 | 47.45 | 0 | 150 | 871.8 | 0.5 |