Primary brain tumours as second primary: a novel association between meningioma and colorectal cancer

In a previous study, a decreased risk for first degree relatives of patients with astrocytoma has been observed for breast and colorectal cancer. The aim of this study was to examine the associations between breast and colorectal cancer as first primary cancer and the risk of developing astrocytoma and meningioma as a second primary cancer. Two cohorts were constructed, one from all cases with breast cancer (1,036,466 person-years) and one from all cases of colorectal cancer (572,422 person-years) in Sweden during the period 1958-1994. The risk of developing astrocytoma and meningioma after breast or colorectal cancer was calculated. A significant increased risk for developing meningioma was seen after colorectal cancer, standardized incidence ratio (SIR) 1.60 confidence interval (CI; 1.32-1.94) and after breast cancer, SIR 1. 57 CI (1.36-1.81). The previously observed decreased risk for astrocytoma could not be verified in this study. A novel association between meningioma and colorectal cancer, particularly in females, was observed, which justifies further studies to evaluate common aetiological factors.

Familial aggregation of astrocytoma in northern Sweden: an epidemiological cohort study

This population-based cohort study investigated the occurrence of familial astrocytoma among first-degree relatives of patients with astrocytoma diagnosed between 1985 and 1993 in the northern region of Sweden. The 432 cases received a questionnaire. They were asked to provide names and cancer diagnoses of first-degree relatives. Of the 297 answering, a cohort was constructed of their 1,890 first-degree relatives (FDR). A significantly increased risk [standardized incidence ratio, SIR = 2.12, 95% confidence interval (CI) = 1.18-3.49] was shown for developing primary brain tumors (PBT). In 4.7% (14/297) of the families, a PBT was found. Interestingly, the increased risk was for astrocytoma only (SIR = 3.12, 95% CI 1.42-5.92), and not for other PBT (SIR 0.90, 95% CI 0.18-2.64). When the cohort was divided according to the median age of proband, most of the increased risk was restricted to the younger cohort (SIR = 4.71, 95% CI 1.52-10.99). Surprisingly, a significantly decreased risk for breast cancer and colon cancer was shown. The finding that the increased risk is restricted to astrocytoma only is a novel one. This study implies that familial aggregation of astrocytoma exists; the familial clustering occurs in a small fraction of astrocytoma, and might be explained by inherited factors.

Can alpha-tocopherol and beta-carotene supplementation reduce adverse radiation effects on salivary glands?

In this study, we evaluated whether supplementation with antioxidant vitamins can reduce the adverse effects of irradiation on the salivary glands in the rat. Four groups of adult Sprague-Dawley rats were given a basic diet providing 0.6 mg alpha-tocopherol and no beta-carotene per day. In two groups the basic diet was supplemented with 3.4 mg alpha-tocopherol and 6 mg beta-carotene per day from 14 days before irradiation until 12 days after completed irradiation. One group of rats given basic diet and one group given supplemented diet were irradiated with 7 Gy daily for five consecutive days. Isoproterenol and pilocarpine-stimulated whole saliva was collected from all rats 2, 4 and 26 weeks after irradiation. Vitamin-supplemented irradiated rats had higher secretion rates on all three occasions compared with those of irradiated rats given basic diet. The changes in saliva composition seen in irradiated rats were less accentuated in vitamin-supplemented, irradiated rats. The proportions of acinar cells were significantly decreased both in parotid and submandibular glands 26 weeks after irradiation. Supplementation with alpha-tocopherol and beta-carotene did not alter the morphology of the glands.