Table 2.
Treatment Adherence, According to Chemotherapy Regimen and Duration of Therapy.*
| Measurement of Treatment Adherence | FOLFOX | CAPOX | ||||
|---|---|---|---|---|---|---|
| 3 Mo (N = 3870) | 6 Mo (N = 3893) | P Value | 3 Mo (N = 2554) | 6 Mo (N = 2517) | P Value | |
| Extent of therapy | ||||||
| Therapy duration | ||||||
| Median (IQR) — wk | 12 (12–12) | 24 (20–24) | 12 (12–12) | 24 (18–24) | ||
| Simple range — wk | 2–24 | 2–44 | 3–24 | 3–36 | ||
| Missing data — no. (%) | 2 (0.1) | 6 (0.2) | 0 | 1 (<0.1) | ||
| Completion of cycles — no. (%) | ||||||
| Received planned no. of cycles | 3459 (89.4) | 2731 (70.2) | <0.001† | 2167 (84.8) | 1612 (64.0) | <0.001† |
| Did not receive planned no. of cycles | 345 (8.9) | 1123 (28.8) | 321 (12.6) | 858 (34.1) | ||
| Received more than planned no. of cycles | 42 (1.1) | 8 (0.2) | 21 (0.8) | 1 (<0.1) | ||
| Missing data | 24 (0.6) | 31 (0.8) | 45 (1.8) | 46 (1.8) | ||
| Percentage of dose delivered | ||||||
| Fluorouracil‡ | <0.001§ | NA | NA | |||
| Mean — % | 92.4±22.7 | 81.6±26.6 | ||||
| Median (IQR) — % | 99.8 (89.2–100) | 89.9 (73.8–100) | ||||
| Simple range — %¶ | 9.4–362.7 | 1.2–398.1 | ||||
| Missing data — no. (%) | 28 (0.7) | 40 (1.0) | ||||
| Capecitabine | NA | NA | <0.001§ | |||
| Mean — % | 91.2±23.5 | 78.0±29.4 | ||||
| Median (IQR) — % | 100 (87.5–100) | 87.5 (62.5–100) | ||||
| Simple range — %¶ | 25.0–393.8 | 0.4–339.2 | ||||
| Missing data — no. (%) | 56 (2.2) | 58 (2.3) | ||||
| Oxaliplatin | <0.001§ | <0.001§ | ||||
| Mean — % | 91.4±19.9 | 72.8±25.6 | 89.8±21.7 | 69.3±28.3 | ||
| Median (IQR) — % | 99.5 (88.6–100) | 78.9 (56.1–93.7) | 100 (87.7–100) | 75.0 (50.0–95.2) | ||
| Simple range — %¶ | 14.7–284.4 | 4.9–249.1 | 25.0–200.0 | 10.9–146.3 | ||
| Missing data — no. (%) | 4 (0.1) | 6 (0.2) | 8 (0.3) | 2 (0.1) | ||
| Dose intensity | ||||||
| Difference between capecitabine or fluorouracil and oxaliplatin in percentage of dose delivered — no. (%)‖ | <0.001† | <0.001† | ||||
| <10 percentage points | 3601 (93.0) | 2701 (69.4) | 2242 (87.8) | 1761 (70.0) | ||
| 10 to <20 percentage points | 127 (3.3) | 404 (10.4) | 131 (5.2) | 230 (9.1) | ||
| 20 to 30 percentage points | 39 (1.0) | 287 (7.4) | 47 (1.8) | 146 (5.8) | ||
| >30 percentage points | 71 (1.8) | 459 (11.8) | 70 (2.7) | 321 (12.8) | ||
| Missing data | 32 (0.8) | 42 (1.1) | 64 (2.5) | 59 (2.3) | ||
Plus–minus values are means ±SD. Percentages may not total 100 because of rounding. IQR denotes interquartile range, and NA not applicable.
This P value was calculated by means of the chi-square test.
The listed values are for both infusion and bolus of fluorouracil.
This P value was calculated by means of the Kruskal–Wallis test.
A total of 30 patients (0.2%) underwent longer treatment than the assigned duration, which resulted in an upper-range percentage of more than 150%.
For each patient, the absolute difference was calculated as percentage of the dose of capecitabine or fluorouracil that was delivered minus the percentage of the dose of oxaliplatin that was delivered, as measured in percentage points. A larger between-group difference indicates that a patient discontinued oxaliplatin earlier or had a greater dose reduction in oxaliplatin than in capecitabine or fluorouracil.