Direct exposure to asbestos was determined from responses to three types of questions: specific queries as to any exposure to asbestos; occupational or non-vocational participation in any of nine specific activities thought to entail exposure to asbestos; and analysis of lifetime work histories. Indirect exposures were assessed through residential histories and reported contact with family members exposed to asbestos. Results-Among men with pleural mesothelioma the attributable risk (AR) for exposure to asbestos was 88% (95% confidence interval (95% CI) 76-95%).For men, the AR ofperitoneal cancer was 58% (95% CI 20-89%/6). For women (both sites combined), the AR was 23% (95% CI 3-72%). The large differences in AR by sex are compatible with the explanations: a lower background incidence rate in women, lower exposure to asbestos, and greater misclassification among women.Conclusions-Most of the pleural and peritoneal mesotheliomas in the men studied were attributable to exposure to asbestos. The situation in women was less definitive. (Occup Environ Med 1994;51:804-81 1)

Mortality through 1975 in US Army veterans released from prisoner-of-war camps following World War II (Europe, Pacific) and the Korean conflict and in several non-prisoner groups is compared using death rates and standard mortality ratios. The World War II Pacific and Korean conflict experience reveal increased risk of dying among former prisoners which, though diminishing with time, persist for 9 and 13 years, respectively. Mortality from tuberculosis and from trauma contributes to the increase among Pacific ex-prisoners, while for Korea the increase is limited to trauma. An excess of deaths due to cirrhosis of the liver in all three former prisoner groups appeared from about the 10th follow-up year. While the reported mortality experience for World War II spans 30 calendar years and for Korea 22 years, no evidence of increased aging among former prisoners of war is seen in mortality from the chronic and degenerative diseases.

In 1964 the Veterans Administration Surgical Adjuvant Group (VASAG) initiated a large-scale, controlled, randomized protocol to study the role of low-dose preoperative irradiation (2000-2500 rads/10fractions/12 days) in patients with operable adenocarcinoma of the sigmoid colon and rectum. This report analyzes the data in 700 patients, all at 5-year risk. There appears to be a definate benefit to irradiated patients who undergo abdominoperineal resections, when compared with the controls. This advantage is reflected in improvement of 5-year survival, and reduction in lymph node invasion, local recurrence, and distant metastases. A second protocol has been initiated in 30 VA hospitals employing a higher dose (3150 rads) to extended portals (toL2) to male patients who require abdominoperineal resections.

No abstract

We evaluated the risk of acute nonlymphocytic leukemia, acute myelodysplastic syndrome, and preleukemia in 3633 patients with gastrointestinal cancer who were treated in nine randomized clinical trials. Among 2067 patients given semustine (methyl-CCNU) as adjuvant therapy, leukemic disorders developed in 14, whereas only one leukemic disorder (acute nonlymphocytic leukemia) occurred among 1566 patients given other therapies (relative risk = 12.4; 95 per cent confidence interval = 1.7 to 250). The six-year cumulative mean risk (+/- S.E.) of acquiring a leukemic disorder after treatment with semustine was 4.0 +/- 2.2 per cent; the incidence rate was 2.3 cases per 1000 persons per year. Risk increased significantly with time after treatment. The risk of leukemic disorders did not differ according to sex, race, age at treatment, or initial tumor type, nor was it enhanced by concomitant radiotherapy or immunotherapy. In addition, no excess of acute nonlymphocytic leukemia was seen in 44,370 patients treated for gastrointestinal cancer in Connecticut during the period 1935 to 1974, before the advent of nitrosourea chemotherapy. This study provides quantitative evidence that nitrosoureas are leukemogenic in human beings and confirms previous observations that adjuvant chemotherapy with alkylating agents may increase the risk of leukemia.

In a prospective randomized trial, 700 patients with a confirmed histological diagnosis of adenocarcinoma of the rectum or rectosigmoid were randomized to receive radiotherapy prior to operation (2000 to 2500 rads in two weeks) or surgery alone. Five year observed survival in the 453 patients on whom "curative" resection was possible was 48.5% in the X-ray treated group compared with 38.8% in controls, while in the 305 having low lying lesions requiring abdominoperineal resection, survival in the treated group was 46.9% compared with 34.3% in controls. Although suggestive of a treatment benefit, neither is considered statistically significant. Histologically positive lymph nodes were found in 41.2% of the control group and in only 27.8% of the patients receiving radiotherapy. Reveiw of all patients who died during the study shows a consistently lower death rate from cancer in the radiotherapy group. Although this study suggests a treatment benefit from preoperative radiotherapy, further studies now in progress by this group and others are necessary to determine the optimal dose regimen.

No abstract

In a prospective randomized trial, 361 male patients with histologically proven adenocarcinoma of the rectum, judged preoperatively to require abdominoperineal resection (APR), were treated by surgery alone or were given 3,150 rads of preoperative radiotherapy. Surgical resection was done on 320 patients, 262 having "curative" APR. Only moderate symptoms from radiotherapy were noted and postoperative complications and 30-day mortality were similar in both groups. Five-year survival for curative APR was the same in both groups (50% for both treated and control patients). The incidence of positive lymph nodes in the resected specimens was 35% in treated and 41% in controls. In the first preoperative radiotherapy trial conducted by the group, 5-year survival in patients undergoing "curative" APR was 47% in treated versus 34% in control groups. Additionally, the difference in positive lymph nodes in the resected specimens was substantially greater in the first trial (26% in treated versus 44% in controls).