**Question:** Earliest symptom of carcinoma rectum is

A. Change in bowel habits
B. Anal itching
C. Localized pain
D. Change in stool consistency

**Core Concept:** Carcinoma rectum is a malignant tumor that develops in the rectum, a part of the gastrointestinal tract. Early symptoms may indicate the presence of this cancer and prompt further diagnostic evaluation.

**Why the Correct Answer is Right:**

The correct answer is A: Change in bowel habits. Early symptoms of carcinoma rectum often involve gastrointestinal disturbances. Change in bowel habits, such as constipation or diarrhea, along with altered stool consistency (option D), are common presentations of rectal cancer. Anal itching (option B) may also occur due to local inflammation or irritation, but it is not specific to carcinoma rectum. Localized pain (option C) can be present but is not the earliest symptom in most cases.

**Why Each Wrong Option is Incorrect:**

Option B (anal itching) is not specific to carcinoma rectum but can be caused by other conditions like hemorrhoids, anal fissure, or infectious diseases.

Option C (localized pain) may be present in later stages of carcinoma rectum but is not the earliest symptom.

Option D (change in stool consistency) is similar to option A but focuses more on the alteration in stool consistency, which is also a common symptom early in the disease process.

**Clinical Pearl:** Early recognition of these symptoms is crucial for prompt diagnosis and improved prognosis of carcinoma rectum. Patients with persistent gastrointestinal disturbances should be evaluated for possible rectal cancer to prevent delays in appropriate treatment.