## Epidemiology of Colorectal Cancer in India **Key Point:** The rectosigmoid region (including the rectum and sigmoid colon) accounts for approximately 60–70% of all colorectal cancers in India, making it the most common site. ### Geographic and Anatomic Distribution | Site | Frequency in India | Frequency in West | | --- | --- | --- | | Rectosigmoid + Rectum | 60–70% | 40–50% | | Caecum + Ascending colon | 15–20% | 20–25% | | Transverse colon | 5–10% | 10–15% | | Descending colon | 5–10% | 5–10% | **High-Yield:** The predominance of left-sided (rectosigmoid) cancers in India differs from the Western pattern, where right-sided cancers are increasingly common. This is attributed to: - Dietary factors (low fibre intake, high refined carbohydrates) - Genetic predisposition in Indian populations - Screening practices (colonoscopy detects proximal lesions earlier in the West) **Clinical Pearl:** Rectosigmoid cancers present earlier with symptoms (bleeding per rectum, change in bowel habits) compared to right-sided cancers, which may present late with anaemia or obstruction. **Tip:** When asked about colorectal cancer site in an Indian context, always think **rectosigmoid first**. This is a high-yield fact for NEET PG.
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