Table 5.
Variation in RR of Meningioma Across Different Levels of Intrathecal Methotrexate Exposure
| Level of Exposure, mg/m2 | Cases |
Controls |
RRs |
|||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Unadjusted |
Adjusted for Radiation Exposure* |
|||||||||
| No. | Mean Dose (mg/m2) | No. | Mean Dose (mg/m2) | RR | 95% CI | P | RR | 95% CI | P | |
| Incomplete information | 22 | 22 | ||||||||
| 0 | 79 | 97 | 1 | 1 | ||||||
| 1-39 | 12 | 31 | 4 | 34 | 4.1 | 1.2 to 14.1 | .024 | 15.4 | 2.2 to 179.6 | .004 |
| 40-69 | 5 | 49 | 7 | 52 | 1.2 | 0.3 to 4.7 | .817 | 10.8 | 1.3 to 143.0 | .027 |
| ≥ 70 | 16 | 542 | 4 | 82 | 6.4 | 1.7 to 23.5 | .006 | 35.6 | 4.8 to 599.4 | < .001 |
| Total† | 134 | 134 | ||||||||
NOTE. Four and two of the 33 exposed patients and 15 exposed controls, respectively, received leucovorin after intrathecal methotrexate.
Abbreviation: RR, relative risk.
*
Adjusted for radiation fitted as a linear trend in continuous cumulative radiation exposure (model 2).
†
Likelihood ratio test for evidence of heterogeneity in RRs across different levels of exposure to intrathecal methotrexate: P for unadjusted analysis = .002; P for adjusted analysis = .001.