Benzene exposure and risk of lymphohaematopoietic cancers in 25 000 offshore oil industry workers

BACKGROUND

The aim of this work was to examine the risk of lymphohaematopoietic (LH) cancer according to benzene exposure among offshore workers.

METHODS

Cancer registry data were used to identify 112 cancer cases diagnosed during 1999-2011 in a cohort of 24 917 Norwegian men reporting offshore work between 1965 and 1999. Analyses were conducted according to a stratified case-cohort design with a reference subcohort of 1661 workers. Cox regression was used to estimate hazard ratios with 95% confidence intervals, adjusted for other benzene exposure and smoking.

RESULTS

Most workers were exposed to benzene for <15 years. The upper range values of average intensity and cumulative exposure were estimated to 0.040 p.p.m. and 0.948 p.p.m.-years, respectively. Risks were consistently elevated among exposed workers for all LH cancers combined and for most subgroups, although case numbers were small and yielded imprecise risk estimates. There was evidence of dose-related risk patterns according to cumulative exposure for acute myeloid leukaemia (AML), multiple myeloma (MM) (P trends 0.052 and 0.024, respectively), and suggestively so for chronic lymphocytic leukaemia (CLL) according to average intensity (P trend 0.094).

CONCLUSIONS

Our results support an association between cumulative and intensity metrics of low-level benzene exposure and risk for AML, MM, and suggestively for CLL.

Short-term survival of ovarian cancer patients waiting more than six weeks after surgery before chemotherapy is given

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Background: To investigate the impact on short-term survival of time between surgery and start of first chemotherapy cycle in patients with advanced ovarian cancer. Methods: This prospective, population-based study comprised 371 patients with epithelial ovarian, tubal or peritoneal cancer diagnosed in 2002–2003. All patients underwent primary surgery, followed at different intervals by chemotherapy. The data were derived from notifications to the Norwegian Cancer Registry and included medical, surgical and histopathological records. Kaplan-Meier plots were used to show differences in survival, and Cox regression analysis was used to show the effect of prognostic factors on survival, expressed as hazard ratios (HRs). Results: No difference in survival between patient groups was seen when time between surgery and start of chemotherapy was divided into quartiles. The group of patients with interval between surgery and chemotherapy less than six weeks had inferior survival if they had residual disease after surgery. Adjusted HR = 2.36 (95% CI, 1.22–4.57). However, in the patient groups with interval more than six weeks, there was no significant difference in survival between patients without and with residual disease. Adjusted HR = 1.35 (0.51–3.56) versus HR = 1.64 (0.76–3.57). Conclusions: The interval between surgery and start of chemotherapy had no major impact on short-term survival after ovarian cancer. Patients might be included in chemotherapy trials when interval between surgery and start of chemotherapy is more than six weeks.

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No significant financial relationships to disclose.

Improved short-term survival for advanced ovarian, tubal, and peritoneal cancer patients operated at teaching hospitals

The aim of this study was to study the impact of hospital level and surgical skill on short-term survival of advanced ovarian, tubal, and peritoneal cancer patients in a prospective population-based study. All 198 women with a diagnosis of advanced epithelial invasive ovarian, tubal, and peritoneal cancer in Norway who underwent surgery during 2002 were included in this study. The data were derived from notifications to the Norwegian Cancer Registry and from medical, surgical, and histopathologic records. The hospitals were grouped into teaching and nonteaching hospitals (NTH), and the operating physicians were classified according to specialty (specialist gynecologist, gynecologist, and surgeon). The follow-up period was from 455 to 820 days. The short-term survival at 450 days was 79% for women operated at teaching hospitals (TH) and 62% at NTH (P= 0.02). After simultaneous adjustment for seven prognostic factors and residual disease, the risk of death within 600 days at NTH was unchanged compared to TH, hazard ratio 1.83. The women operated on by specialist compared to general gynecologists had a 20% increased short-term survival (P < 0.0001). TH and specialist gynecologists achieved better short-term survival of patients operated for advanced ovarian, tubal, and peritoneal cancer. Centralization and specialization of ovarian cancer surgery might improve the outcome for this patient group.