**Core Concept**
Papillary thyroid carcinoma (PTC) is a common type of thyroid cancer that can metastasize to cervical lymph nodes. The management of cervical lymph node involvement in PTC is a critical aspect of treatment, as it affects the prognosis and survival of the patient.

**Why the Correct Answer is Right**
Cervical lymph node involvement in PTC is typically managed with radioactive iodine therapy, which is a form of internal radiation therapy. Radioactive iodine is taken up by thyroid cells and their metastases, allowing for targeted destruction of cancer cells while minimizing damage to surrounding tissues. This treatment approach is particularly effective in PTC, as thyroid cells concentrate iodine, making them susceptible to radioactive iodine therapy.

**Why Each Wrong Option is Incorrect**
* **Option A:** Surgery alone may not be sufficient to treat cervical lymph node involvement in PTC, as it may not address the entire extent of the disease.
* **Option B:** External beam radiation therapy may be used in some cases, but it is not the primary treatment for cervical lymph node involvement in PTC.
* **Option C:** Chemotherapy is not typically used as a primary treatment for PTC, especially in cases with cervical lymph node involvement.

**Clinical Pearl / High-Yield Fact**
Remember that radioactive iodine therapy is a key component of treatment for cervical lymph node involvement in PTC, and it is essential to consider the patient's overall clinical picture, including the extent of disease, to determine the most appropriate treatment approach.

**Correct Answer:** B. External beam radiation therapy may be used in some cases, but it is not the primary treatment for cervical lymph node involvement in PTC.