**Core Concept**
Anaplastic carcinoma, also known as anaplastic thyroid carcinoma, is a rare and aggressive form of thyroid cancer. It accounts for approximately 1-2% of all thyroid cancer cases and is characterized by its rapid growth and resistance to treatment. The disease often presents with advanced local invasion and distant metastasis.

**Why the Correct Answer is Right**
Radiotherapy is a common treatment modality for anaplastic carcinoma, but it is not curative. The disease is often resistant to radiation therapy, and the primary goal of treatment is to palliate symptoms and improve quality of life. Surgery may be considered for patients with limited disease or as a palliative measure, but it is rarely curative.

**Why Each Wrong Option is Incorrect**
**Option A:** Anaplastic carcinoma is indeed more common in elderly patients, often presenting in individuals over the age of 60.
**Option B:** P53 mutations are associated with anaplastic thyroid carcinoma, contributing to its aggressive behavior and poor prognosis.
**Option C:** The disease often infiltrates surrounding neck tissues, including muscles, nerves, and blood vessels, leading to severe local invasion.

**Clinical Pearl / High-Yield Fact**
Anaplastic carcinoma is a highly malignant disease with a poor prognosis, and treatment options are often limited. Palliative care and symptom management are essential components of care, and patients should be referred to multidisciplinary teams for comprehensive management.

**✓ Correct Answer: D. Radiotherapy cures**