Radiation therapy uses high-energy radiation to shrink tumors and kill cancer cells (1). X-rays, gamma rays, and charged particles are types of radiation used for cancer treatment.
1 Lymph nodes of the armpit and neck may also be involved. 2  Viral infections such as infectious mononucleosis may affect the whole body and cause generalized lymph node swelling in various parts of the body, such as neck, armpit or groin.
Groin lymph nodes get lympha from external urogenital organs and skin of the rectum so it is possible that this lymph node enlargement is caused by hemorrhoid which has gotten infected. Painful, movable lymph nodes with regular shapes are most likely caused by inflammation. However groin enlarged lymph node can indicate some cancerous process. That is why, it should not be neglected. It is also possible that this is not a lymph node, but a inguinal hernia. You can perform a simple test.