Pooled analysis of recent studies on magnetic fields and childhood leukaemia.

BACKGROUND: Previous pooled analyses have reported an association between magnetic fields and childhood leukaemia. We present a pooled analysis based on primary data from studies on residential magnetic fields and childhood leukaemia published after 2000. METHODS: Seven studies with a total of 10,865 cases and 12,853 controls were included. The main analysis focused on 24-h magnetic field measurements or calculated fields in residences. RESULTS: In the combined results, risk increased with increase in exposure, but the estimates were imprecise. The odds ratios for exposure categories of 0.1-0.2 µT, 0.2-0.3 µT and ≥0.3 µT, compared with <0.1 µT, were 1.07 (95% CI 0.81-1.41), 1.16 (0.69-1.93) and 1.44 (0.88-2.36), respectively. Without the most influential study from Brazil, the odds ratios increased somewhat. An increasing trend was also suggested by a nonparametric analysis conducted using a generalised additive model. CONCLUSIONS: Our results are in line with previous pooled analyses showing an association between magnetic fields and childhood leukaemia. Overall, the association is weaker in the most recently conducted studies, but these studies are small and lack methodological improvements needed to resolve the apparent association. We conclude that recent studies on magnetic fields and childhood leukaemia do not alter the previous assessment that magnetic fields are possibly carcinogenic.

Surgical strategy for pheochromocytoma: emphasis on the pledge of flank extraperitoneal approach in selected patients.

BACKGROUND: Anterior transabdominal exploration has traditionally been advocated as the standard procedure for pheochromocytoma. However, some authors claim that a flank extraperitoneal approach with accurate unilateral localization is justifiable. METHODS: Retrospective analysis was performed on 87 patients with pheochromocytoma to determine the appropriateness of extraperitoneal exploration. RESULTS: There were 45 men and 42 women with a mean age of 44.7 years (range, 16 to 83 years). Fifteen patients (17.5%) had pheochromocytoma as a part of multiple endocrine neoplasia (MEN) type 2A, and four had familial pheochromocytoma, von Hippel-Lindau disease, or von Recklinghausen's disease. All tumors detected by preoperative localization studies were correctly identified and were resected through flank extraperitoneal (45 patients), transabdominal (28), thoracoabdominal (13), and posterior (1) approaches. Tumors were extraadrenal in 14, multiple in 22, bilateral in 12, and unequivocally malignant in 2 patients at the initial operation. Two patients died during the immediate postoperative period, giving an operative mortality of 2.3%. Two patients had persistent disease. During follow-up within a mean period of 5 years (range, 1 month to 13.7 years) 8 patients (9.1%) experienced recurrence or metastasis. Other than the patients with MEN 2, recurrence was not attributable to the operative approach. CONCLUSIONS: If a preoperative localization study is accurate, an extraperitoneal approach is justifiable for many patients with pheochromocytomas.

Extremely low-frequency magnetic fields and survival from childhood acute lymphoblastic leukemia: an international follow-up study.

A previous US study reported poorer survival in children with acute lymphoblastic leukemia (ALL) exposed to extremely low-frequency magnetic fields (ELF-MF) above 0.3 µT, but based on small numbers. Data from 3073 cases of childhood ALL were pooled from prospective studies conducted in Canada, Denmark, Germany, Japan, UK and US to determine death or relapse up to 10 years from diagnosis. Adjusting for known prognostic factors, we calculated hazard ratios (HRs) and 95% confidence intervals (CI) for overall survival and event-free survival for ELF-MF exposure categories and by 0.1 µT increases. The HRs by 0.1 µT increases were 1.00 (CI, 0.93-1.07) for event-free survival analysis and 1.04 (CI, 0.97-1.11) for overall survival. ALL cases exposed to >0.3 µT did not have a poorer event-free survival (HR=0.76; CI, 0.44-1.33) or overall survival (HR=0.96; CI, 0.49-1.89). HRs varied little by subtype of ALL. In conclusion, ELF-MF exposure has no impact on the survival probability or risk of relapse in children with ALL.