This is a bonus story from Adam Feuerstein, whose biotech coverage usually runs only on RealMoney . We're offering it today to TheStreet.com readers. To read Adam's commentary every day, click here for information on a free trial to RealMoney. NEW ORLEANS -- ImClone Systems' ( IMCL) cancer drug Erbitux, when added to radiation therapy, nearly doubles survival for patients with advanced head and neck cancer, according to results from a phase III study made public Saturday at the annual meeting of the American Society of Clinical Oncology (also known as ASCO). It's not yet clear whether the positive data from this study will prompt ImClone and partner Bristol-Myers Squibb ( BMY) to seek an expansion of Erbitux's label from the Food and Drug Administration. But the fact that Erbitux appears to help some patients with head and neck cancer live longer -- the most important test of a cancer drug's efficacy, generally speaking -- will likely convince oncologists to begin using the drug "off label" to treat this form of cancer. Erbitux is already approved and marketed as a treatment for advanced colon cancer. There are about 40,000 people in the U.S. diagnosed each year with head and neck cancer. Of these, about 30% are currently treated with radiation alone and would therefore be candidates for the addition of Erbitux, according to a recent survey from investment bank SG Cowen. This equates to a $150 million market opportunity for ImClone, estimates Cowen, adding that sales could quadruple if doctors use Erbitux more broadly in head and neck cancer, just as they have started to do in colon cancer. (Cowen doesn't have an investment banking relationship with ImClone.) The 424 patients enrolled in this phase III study were all diagnosed with advanced head and neck cancer that had not yet spread, or metastasized, to other parts of the body. About half the patients were treated with a combination of high-dose radiation plus Erbitux, the remaining half with high-dose radiation alone. Patients receiving radiation and Erbitux had a median survival of 54 months, compared to a median survival of 28 months for patients receiving radiation alone. These results were statistically significant.