Screening of prostate Ca commonly done bya) DRE (digital rectal exam)b) USGc) MRId) PSAe) CT scan

**Core Concept**
Prostate cancer screening involves a combination of clinical examination, imaging techniques, and biomarkers to detect abnormalities that may indicate cancer. The goal is to identify prostate cancer at an early stage when it is more treatable.

**Why the Correct Answer is Right**
PSA (Prostate-Specific Antigen) screening is widely used for prostate cancer detection. Elevated PSA levels can indicate prostate cancer, but they can also be caused by benign conditions such as prostatitis or benign prostatic hyperplasia (BPH). The PSA test measures the level of PSA in the blood, which is produced by the prostate gland. When prostate cancer is present, cancer cells can produce more PSA, leading to an elevated blood level.

**Why Each Wrong Option is Incorrect**
* **Option A:** DRE (digital rectal exam) is a clinical examination where a healthcare provider inserts a gloved finger into the rectum to feel the prostate gland. While DRE can help identify abnormalities, such as nodules or irregularities, it is not as sensitive as PSA screening for detecting prostate cancer.
* **Option B:** USG (ultrasound) can be used to visualize the prostate gland and detect abnormalities, but it is not typically used for screening.
* **Option C:** MRI (magnetic resonance imaging) can be used to evaluate the prostate gland in more detail, but it is not a primary screening tool.
* **Option D:** CT (computed tomography) scan is not typically used for prostate cancer screening.

**Clinical Pearl / High-Yield Fact**
The PSA test has limitations, and elevated levels can be caused by non-cancerous conditions. Therefore, a high PSA level should be followed by further evaluation, including DRE, USG, and biopsy, to confirm the diagnosis.

**Correct Answer: D. PSA**