Tamoxifen treatment for breast cancer should continue. In addition, the relative risk of endometrial cancer observed in B-14 tamoxifen-treated patients is consistent with the twofold relative risk used in the initial risk-benefit computation for the NSABP breast cancer prevention trial.

We conducted a randomized, double-blind, placebo-controlled trial of postoperative therapy with tamoxifen (10 mg twice a day) in 2644 patients with breast cancer, histologically negative axillary nodes, and estrogen-receptor-positive (greater than or equal to 10 fmol) tumors. No survival advantage was observed during four years of follow-up (92 percent for placebo vs. 93 percent for tamoxifen; P = 0.3). There was a significant prolongation of disease-free survival among women treated with tamoxifen, as compared with those receiving placebo (83 percent vs. 77 percent; P less than 0.00001). This advantage was observed in both the patients less than or equal to 49 years old (P = 0.0005) and those greater than or equal to 50 (P = 0.0008), particularly in the former, among whom the rate of treatment failure was reduced by 44 percent. Multivariate analysis indicated that all subgroups of patients benefited. Tamoxifen significantly reduced the rate of treatment failure at local and distant sites, tumors in the opposite breast, and the incidence of tumor recurrence after lumpectomy and breast irradiation. The benefit was attained with a low incidence of clinically appreciable toxic effects. The magnitude of the improvement obtained does not preclude the need for future trials in which patients given tamoxifen could serve as the control group in an evaluation of potentially better therapies. Tamoxifen treatment is justified in patients who meet the eligibility criteria of the present study and who refuse to participate in those trials. Since patients with tumors too small for conventional analysis of estrogen-receptor and progesterone-receptor concentrations were not eligible for this study, no information is available to indicate that such patients should receive tamoxifen.

Summary A deletion on human chromosome 16p11.2 is associated with autism spectrum disorders. We deleted the syntenic region on mouse chromosome 7F3. MRI and high-throughput single-cell transcriptomics revealed anatomical and cellular abnormalities, particularly in cortex and striatum of juvenile mutant mice (16p11+/−). We found elevated numbers of striatal medium spiny neurons (MSNs) expressing the dopamine D2 receptor (Drd2+) and fewer dopamine-sensitive (Drd1+) neurons in deep layers of cortex. Electrophysiological recordings of Drd2+ MSN revealed synaptic defects, suggesting abnormal basal ganglia circuitry function in 16p11+/− mice. This is further supported by behavioral experiments showing hyperactivity, circling, and deficits in movement control. Strikingly, 16p11+/− mice showed a complete lack of habituation reminiscent of what is observed in some autistic individuals. Our findings unveil a fundamental role of genes affected by the 16p11.2 deletion in establishing the basal ganglia circuitry and provide insights in the pathophysiology of autism.

Data are presented from 1,166 patients with Dukes B and C carcinoma of the colon who were entered into the National Surgical Adjuvant Breast and Bowel Project (NSABP) Protocol C-01 between November 1977 and February 1983. Patients were randomized to one of three therapeutic categories: 1) no further treatment following curative resection (394 patients); 2) postoperative chemotherapy consisting of 5-fluorouracil, semustine, and vincristine (379 patients); or 3) postoperative BCG (393 patients). The average time on study was 77.3 months. A comparison between patients receiving postoperative adjuvant chemotherapy and those treated with surgery alone indicated that there was an overall improvement in disease-free survival (P = .02) and survival (P = .05) in favor of the chemotherapy-treated group. At 5 years of follow-up, patients treated with surgery alone were at 1.29 times the risk of developing a treatment failure and at 1.31 times the likelihood of dying as were similar patients treated with combination adjuvant chemotherapy. Comparison of the BCG-treated group with the group treated with surgery alone indicated that there was no statistically significant difference in disease-free survival (P = .09). There was, however, a survival advantage in favor of the BCG-treated group (P = .03). At 5 years of follow-up, patients randomized to the surgery-alone arm were at 1.28 times the risk of dying as were similar patients treated with BCG. Further investigation disclosed that this survival advantage in favor of BCG was a result of a diminution in deaths that were non-cancer related. When analyses were conducted on which events not related to cancer recurrence were eliminated, the survival difference between the BCG and control groups became nonsignificant (P = .40); the cumulative odds at 5 years decreased from 1.28 to 1.10. The findings from this study are the first from a randomized prospective clinical trial to demonstrate that a significant disease-free survival and survival benefit can be achieved with postoperative adjuvant chemotherapy in patients with Dukes B and C carcinoma of the colon who have undergone curative resection.

We studied the possibility that the addition of tamoxifen to L-phenylalanine mustard combined with 5-fluorouracil enhances the benefit from the latter two drugs that has been observed in women with primary breast cancer and positive axillary nodes. Recurrence of disease was reduced at two years in patients given the three-drug regimen whose tumor estrogen-receptor levels were greater than or equal to 10 fmol. Among patients greater than or equal to 50 years old treatment failure was significantly reduced (P less than 0.001): by 51 per cent in those with one to three positive nodes and by 64 per cent in those with four or more. Higher receptor levels were associated with a greater probability of disease-free survival. Patients less than or equal to 49 years old were less responsive: those with one to three positive nodes received no benefit from tamoxifen at any receptor level, whereas those with four or more appeared to have reduced treatment failure associated with higher receptor levels. This adjuvant chemotherapy is not indicated in patients less than or equal to 49 years old whose tumor receptor levels are below 10 fmol; there is a suggestion of benefit in patients greater than or equal to 50 years old whose levels are low.