TABLE 4.
Relative risk (rate ratio) for incidence rate of hypothyroidism according to type of treatment with chemotherapy agents in the Childhood Cancer Survivor Study cohort.
| Characteristic | Cases | PYR/10,000 | RR (95% CI)a |
|---|---|---|---|
| Any chemotherapy & type of childhood cancer | |||
| No chemotherapyb | 190 | 3.5 | 1.0 |
| Any chemotherapy & leukemia | 193 | 6.5 | 1.1 (0.2–7.1) |
| Any chemotherapy & CNS cancer | 58 | 0.4 | 6.7 (3.0–14.8) |
| Any chemotherapy & HL | 148 | 1.2 | 0.8 (0.0–20.4) |
| Any chemotherapy & other cancers | 171 | 6.7 | 1.8 (0.7–4.5) |
| Pc =0.14 | |||
| Any alkylating agentsd | |||
| No | 326 | 9.2 | 1.0 |
| Yes | 433 | 9.2 | 1.8 (1.1–3.0) |
| Pc =0.04 | |||
| Any anthracyclinesc | |||
| No | 522 | 11.3 | 1 |
| Yes | 237 | 7.1 | 1.1 (0.6–2.1) |
| Pc =0.85 | |||
| Any bleomycin | |||
| No | 690 | 17.6 | 1 |
| Yes | 69 | 0.8 | 3.4 (1.6–7.3) |
| Pc =0.03 | |||
| Any platinum-based compounds | |||
| No | 725 | 17.7 | 1 |
| Yes | 34 | 0.7 | 1.1 (0.3–4.8) |
| Pc = 0.88 | |||
| Any epipodophyllotoxins | |||
| No | 696 | 17.2 | 1 |
| Yes | 63 | 1.3 | 1.5 (1.0–2.3) |
| Pc =0.08 | |||
| Alkylating Agents | |||
| CCNU (Lomustine) | |||
| No | 704 | 18.0 | 1.0 |
| Yes | 55 | 0.4 | 3.0 (1.5–5.3) |
| Pc <0.01 | |||
| CCNU, mg/m2 | |||
| 0 | 704 | 18.0 | 1.0 |
| >0- < 411.18 | 13 | 0.1 | 1.0 (0.1–7.4) |
| 411.18- <800.0 | 23 | 0.1 | 5.0 (2.5–9.9) |
| >800.0 | 12 | 0.04 | 8.2 (3.6–18.9) |
| Pc <0.01 | |||
| CCNU & type of cancer | |||
| No CCNU | 704 | 18.0 | 1.0 |
| CCNU & CNS cancer | 35 | 0.2 | 3.6 (1.2–7.1) |
| CCNU & other cancers | 20 | 0.2 | 2.6 (0.8–5.6) |
| Pc =0.03 | |||
| BCNU (Carmustine) | |||
| No | 729 | 17.7 | 1.0 |
| Yes | 30 | 0.7 | 1.1 (0.5–2.0) |
| Pc 0.50 | |||
| Cyclophosphamide | |||
| No | 450 | 10.3 | 1.0 |
| Yes | 309 | 8.1 | 1.3 (1.0–1.8) |
| Pc =0.05 | |||
| Cyclophosphamide, mg/m2 | |||
| 0 | 450 | 10.4 | 1.0 |
| >0- < 5323.1 | 120 | 3.0 | 1.3 (0.9–1.9) |
| 5323.1- <11,448.3 | 89 | 2.4 | 1.3 (0.9–1.9) |
| >11,448.3 | 74 | 2.1 | 1.3 (0.9–2.1) |
| Pc =0.36 | |||
| Procarbazine | |||
| No | 598 | 17.1 | 1.0 |
| Yes | 161 | 1.3 | 1.0 (0.4–2.3) |
| Pc >0.50 | |||
| Mechlorethamine | |||
| No | 668 | 17.6 | 1.0 |
| Yes | 91 | 0.9 | 0.7 |
| Pc >0.50 | |||
| Melphalan | |||
| No | 745 | 18.2 | 1.0 |
| Yes | 14 | 0.2 | 2.2 (0.7– 5.2) |
| Pc =0.16 | |||
| Thiotepa | |||
| No | 747 | 18.4 | 1.0 |
| Yes | 12 | 0.05 | 5.7 (0.2–15.2) |
| Pc =0.14 |
RRs adjusted for an additive association for categories of the cross-tabulation of radiation dose to the thyroid and and pituitary, with dose categories as in Table 5, and categories of exposure to classes of chemotherapy agents or chemotherapy drugs/doses. Baseline was adjusted for sex, attained age, type of cancer, and calendar year of follow-up. Type of first cancer included to account for possible differential surveillance and shared predisposition. Patients with missing pituitary dose and missing information on the specific class of chemotherapy agent or chemotherapydrugs/doses were excluded from this analysis. Alkylating agents with fewer than 10 cases (busulfan, chlorambucil and ifosfamide) were not included in this analysis.
Number of cases who did not receive chemotherapy, by type of cancer: leukemia=1, CNS=69, HL=98 and others=22
Likelihood ratio test of homogeneity of risk across categories
Abbreviations: BCNU=bis-chloroethyl-nitrosourea, CCNU=cyclohexyl-chloroethyl-nitrosourea; CI=confidence interval;CNS=central nervous system; HL= Hodgkin lymphoma); PYR=person-years; RR=relative risk (rate ratio); Thiotepa= triethylenethiophosphoramide