Among the highlights in the June 1999 Cancer Watch issue are: Bladder Tumor Associated Antigen (BTAA), Sunscreen Use Linked to Naevi in Children, Fos Expression and Resistance in Breast Cancer, The Pure Antiestrogen ICI 182, 780 is also an Antiprogestin, The Role of Aging in Carcinogenesis, Occupational Solvent Exposure Linked to Kidney Cancer, Low-potency Estrogen and Risk of Endometrial Cancer, Tamoxifen in New Adjuvant Treatments for Breast Cancer, Tamoxifen Reduces Cardiac Risk Factors in Healthy Women, Tamoxifen Benefit is Cost-Effective, With History of LCIS or Atypical Hyperplasia Tamoxifen Benefit is Greater, Hormone Replacement Therapy and Risk of Breast Cancer, Breast Cancer Prevention Study Seeks Volunteers and Chemoprevention of Cancer: Coming of Age?

• Bladder Tumor Associated Antigen (BTAA)
• Sunscreen Use Linked to Naevi in Children
• Fos Expression and Resistance in Breast Cancer
• The Pure Antiestrogen ICI 182, 780 is also an Antiprogestin
• The Role of Aging in Carcinogenesis

• Trichloroethylene, an important industrial solvent is a potent carcinogen and long-term exposure to high dose is linked to mutation of a tumor suppressor gene for kidney cancer.
  

• Low-potency estrogen formulation such as estriol, when administered orally or vaginally may alleviate certain symptoms related to menopause. The low-potency estrogens, previously thought to have few adverse effects on endometrium is found to increase risk of cancer of this tissue.

• For more than 10 years, physicians have known that both chemotherapy and ovarian ablation are effective adjuvant treatments for some premenopausal breast cancer patients. But the combination of the two techniques has not been well studied, at least until final results of several long-term studies appeared at the recent 35th Annual Meeting of the American Society of Clinical Oncology (ASCO) in Atlanta. There, physicians heard results of one study showing that tamoxifen added to a chemohormonal treatment regimen decreased the risk of cancer recurrence, sometimes quite significantly. Also, ovarian ablation achieved with goserelin instead of surgery is reversible in some women, but the resultant disease-free survival time was far less significant than that produced by adding tamoxifen. Since some groups of patients benefited more than others, research continues probing for the optimal target population(s), dosages and drug combinations..

• Tamoxifen, in addition to reducing breast cancer may also prevent heart disease in healthy women by reducing cholesterol, C-reactive protein, and fibrinogen. C-reactive protein is a nonspecific marker of inflammation, and has been linked to increased risk of heart attack and stroke.

• The reduced risks of developing breast cancer (49% and 50% for invasive and noninvasive, respectively) seen for tamoxifen therapy reported in the National Surgical Adjuvant Breast and Bowel Project (NSABP) P-1 Breast Cancer Prevention Trial come with trade offs, both in greater risk of endometrial cancer and in higher costs. Analysts can derive "a cost of life year" saved, however, through economic modeling taking into account savings from disease avoided and additional costs associated with administration of therapy plus potential side effects. That cost can then be compared with that of other therapies already accepted as being cost-effective.

• Tamoxifen therapy can substantially reduce the excess breast cancer risk conferred by prior history of either lobular carcinoma in-situ (LCIS) or atypical hyperplasia, according to a subgroup analysis of the BCPT (Breast Cancer Prevention Trial).

• Long-term use of postmenopausal hormone replacement therapy may increase the risk of breast cancer but this increased risk seems to be confined to histologic type with favorable prognosis.

• Raloxifene, a designer estrogen, shows many beneficial effects of tamoxifen and may not have the adverse effects of the latter. Tamoxifen is used for breast cancer treatment and is being tried in chemoprevention. The National Cancer Institute is launching a clinical trial to compare the effects of tamoxifen and raloxifene in preventing breast cancer among postmenopausal women.

• While there are many promising results in the prevention of experimental tumors in animals, chemoprevention of human cancer is still in its infancy. The development of truly effective compounds require perfect understanding of the cancerogenic processes and the inhibitory or reversing interactions of such agents with malignant transformation. The sometimes long latency of the latter and the still poorly understood role of the individual genetic make-up, together with possible side-effects or even toxicity of "preventive" compounds, all this makes their long-term administration a difficult balancing act between risk and benefits. The interest in improved prevention strategies is growing for obvious reasons: once cancer occurs, it is still a mainly lethal disease. Populist pressure demanding preventive advice results in often semi- or unscientific recommendations of various diets, herbal and "natural" remedies, even meditation, to name a few. On the other hand, innumerable substances have a good track record for their apparent ability to interfere with cancerogenic pathways – albeit in experimental settings; their inconsistent success in human trials is the result of frequently flawed designs and interpretations.

Glossary

• A glossary of unfamiliar words and jargons in Cancer Watch, January-June 1999.