Is intestinal obstruction a symptom of colon cancer?

No: Hopefully it is more rare with good family practitioners making their patients have adequate health surveillance. Typically they are picked up with these screening endoscopies, blood in stool, weight loss etc. Occasionally you will find a stoic individual who ignores symptoms, or avoids doctors, and thus presents with obstruction instead.

All too often: It is not uncommon for colon cancers to not cause symptoms until they reach a size sufficient to block the lumen of the colon; at this point, people will typically present with cramping abdominal pain, severe bloating, and vomiting. These findings often indicate an advanced cancer that may require emergency surgery (+/-stent). The goal of screening is to find cancers before any symptoms develop.