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.
1 A generalized allergic reaction to drugs particularly to penicillin, iodine, sulfa drugs and other medications can initiate enlargement of the lymph nodes. The groin area appears to be swollen, red, warm and tender.  Lymphedema. The lymph channels are blocked causing the lymph fluids to accumulate along the body tissue.