Which are indicators of colorectal cancer? (Select all that apply.)

Colorectal cancer arises from the malignant transformation of adenomatous polyps within the colonic or rectal mucosa. As the tumor invades the intestinal wall, it causes vascular friability and luminal narrowing, leading to systemic and localized symptoms. Early detection via screening is critical because early-stage neoplastic growth often remains asymptomatic until significant tissue infiltration occurs. A. Anemia: Chronic, occult blood loss from the tumor surface leads to iron deficiency anemia, particularly in right-sided colonic lesions. Clients often present with fatigue, pallor, and exertional dyspnea before noticing changes in stool appearance. This systemic manifestation suggests persistent microscopic gastrointestinal hemorrhage. B. Rectal bleeding: Overt hematochezia or melena occurs when the tumor mass ulcerates and erodes into submucosal vessels. Bright red blood is more common with rectal or sigmoid lesions, whereas darker blood suggests a more proximal location. This is a primary warning sign for malignancy. C. Changing bowel habits: Tumor growth can partially obstruct the intestinal lumen, causing a noticeable shift in stool caliber or frequency. Clients may report "pencil-thin" stools, alternating constipation and diarrhea, or a feeling of incomplete evacuation. Persistent changes lasting more than 2 weeks require diagnostic investigation. D. Abdominal cramps: Partial bowel obstruction by the neoplastic mass increases intraluminal pressure as the intestine attempts to force contents past the blockage. This manifests as intermittent, colicky pain or persistent discomfort. Severe cramping may indicate a high-grade obstruction or impending perforation.