Table 3.
Characteristic |
Cases (n = 89) |
Controls (n = 190) |
OR | 95% CI‡ | Pinteraction§ | |||
---|---|---|---|---|---|---|---|---|
Radiation Dose (Gy)* | Procarbazine dose (mg/m2)† | No. | %‡ | No. | %‡ | |||
All patients | < .001 | |||||||
< 25 | < 5,600 | 25 | 29 | 94 | 52 | 1.0 | Referent | |
≥ 25 | < 5,600 | 23 | 26 | 41 | 23 | 2.8 | 1.3 to 6.4 | |
< 25 | ≥ 5,600 | 14 | 16 | 44 | 24 | 1.2 | 0.5 to 2.7 | |
≥ 25 | ≥ 5,600 | 25 | 29 | 2 | 1 | 77.5 | 14.7 to 1,452 | |
Age at HL diagnosis < 30 years | .06 | |||||||
< 25 | < 5,600 | 6 | 15 | 44 | 49 | 1.0 | Referent | |
≥ 25 | < 5,600 | 13 | 33 | 27 | 30 | 7.1 | 1.9 to 36.8‖ | |
< 25 | ≥ 5,600 | 6 | 15 | 17 | 19 | 1.9 | 0.5 to 7.3 | |
≥ 25 | ≥ 5,600 | 15 | 36 | 2 | 2 | 124 | 15.8 to 3,169 | |
Age at HL diagnosis ≥ 30 years | .002 | |||||||
< 25 | < 5,600 | 19 | 40 | 50 | 55 | 1.0 | Referent | |
≥ 25 | < 5,600 | 10 | 21 | 14 | 15 | 1.5 | 0.5 to 4.2‖ | |
< 25 | ≥ 5,600 | 8 | 17 | 27 | 30 | 0.8 | 0.3 to 2.4 | |
≥ 25 | ≥ 5,600 | 10 | 21 | 0 | 0 | ∞ | 8.8 to ∞ | |
Age at stomach cancer diagnosis < 50 years | .13 | |||||||
< 25 | < 5,600 | 5 | 13 | 44 | 50 | 1.0 | Referent | |
≥ 25 | < 5,600 | 13 | 33 | 26 | 30 | 8.6 | 2.3 to 43.9‖ | |
< 25 | ≥ 5,600 | 7 | 18 | 16 | 18 | 2.9 | 0.8 to 11.6 | |
≥ 25 | ≥ 5,600 | 15 | 38 | 2 | 2 | 151 | 17.6 to 4,264 | |
Age at stomach cancer diagnosis ≥ 50 years | < .001 | |||||||
< 25 | < 5,600 | 20 | 43 | 50 | 54 | 1.0 | Referent | |
≥ 25 | < 5,600 | 10 | 21 | 15 | 16 | 1.3 | 0.4 to 3.6‖ | |
< 25 | ≥ 5,600 | 7 | 15 | 28 | 30 | 0.6 | 0.2 to 1.7 | |
≥ 25 | ≥ 5,600 | 10 | 21 | 0 | 0 | ∞ | 8.9 to ∞ | |
Interval from HL to stomach cancer < 15 years | .003 | |||||||
< 25 | < 5,600 | 15 | 37 | 42 | 55 | 1.0 | Referent | |
≥ 25 | < 5,600 | 6 | 15 | 13 | 17 | 1.5 | 0.4 to 5.6‖ | |
< 25 | ≥ 5,600 | 9 | 22 | 22 | 29 | 1.2 | 0.4 to 3.9 | |
≥ 25 | ≥ 5,600 | 11 | 27 | 0 | 0 | ∞ | 10.0 to ∞ | |
Interval from HL to stomach cancer ≥ 15 years | .02 | |||||||
< 25 | < 5,600 | 10 | 22 | 52 | 50 | 1.0 | Referent | |
≥ 25 | < 5,600 | 17 | 37 | 28 | 27 | 4.2 | 1.4 to 14.1‖ | |
< 25 | ≥ 5,600 | 5 | 11 | 22 | 21 | 1.2 | 0.3 to 4.2 | |
≥ 25 | ≥ 5,600 | 14 | 30 | 2 | 2 | 67.0 | 10.5 to 1,407 |
Abbreviations: ABV, doxorubicin, bleomycin, vinblastine; BEACOPP, bleomycin, etoposide, doxorubicin, cyclophosphamide, vincristine, procarbazine, prednisone; HL, Hodgkin lymphoma; OR, odds ratio.
Radiation dose was estimated to the specific site of the stomach tumor (matched location for controls).
Assuming a procarbazine dose of 1,400 mg/m2 per cycle (14 days × 100 mg/m2 per day), ≥ 5,600 mg/m2 corresponds to ≥ four cycles of MOPP or MOPP-like regimens. Other protocols (eg, MOPP-ABV, BEACOPP) include a procarbazine dose of 700 mg/m2 per cycle.
ORs and 95% CIs were adjusted for receipt of any dacarbazine and unknown radiation dose. Patients with unknown radiation dose were excluded from percentages.
Pinteraction between irradiation and procarbazine was calculated using a likelihood ratio test under the multiplicative model.
Stomach cancer risk among patients who received radiation to stomach tumor site ≥ 25 Gy but procarbazine < 5,600 mg/m2 was compared between patient subgroups using a likelihood ratio test. Age at HL diagnosis: OR < 30, 7.1 v OR ≥ 30, 1.5; Phomogeneity = .11. Age at stomach cancer diagnosis: OR < 50, 8.6 v OR ≥ 50, 1.3; Phomogeneity = .05. Interval from HL to stomach cancer: OR < 15, 4.2 v OR ≥ 15, 1.5; Phomogeneity = .30.