Targeted cancer drugs are one of the great hopes for pharmaceutical companies, but a business survey says cancer doctors are limiting visits by sales representatives more than most medical specialists. Whether this is good or bad depends, of course, on your perspective or how you make money. ZS Associates, a global sales and marketing firm, published its spring 2012 AccessMonitor report this week and it says about 61 percent of oncologists placed moderate-to-severe restrictions on visits from pharmaceutical sales reps. The report says oncologists were the most restrictive of the 20 most common medical specialties measured. About 47 percent of cardiologists and 38 percent of primary care physicians restricted sales representative access to the same degree, according to the report.