Exact Sciences Corp. , maker of a colon cancer test, had shares surge 11% in extremely heavy Wednesday trade after the American Cancer Society recommended screening for colon cancers starting five years earlier, at age 45. Colon cancers, which begin in the colon or rectum, are the second leading U.S. cancer killer, according to the Centers for Disease Control and Prevention, and screenings can catch precancerous growths early. The ACS said that its new recommendation, published on Wednesday, was a “qualified” recommendation, meaning that there is evidence of benefit but less certainty about the benefits relative to the harms. The group continues to strongly recommend that adults ages 50 years and older get regularly screened, the frequency of which depends on the test used. Because the ACS recommendation was qualified, not strong, it may not translate to other national recommendations. For Exact Sciences, “we see this event as only directionally positive and unlikely to become reality in the near-term,” said Leerink Partners analyst Puneet Souda. “Still, ACS had a larger loudspeaker and the message is more likely than not to catalyze action at other guiding societies,” Souda said. Colon cancer screening tests include stool-based tests, such as Exact Sciences’ Cologuard, as well as exams like a colonoscopy. Exact Sciences shares have surged 31% over the last three months, compared with a 0.5% rise in the S&P 500 and a 1.3% decline in the S&P 500 .