Targeted Therapy for Head and Neck Cancer. This mode of treatment involves the use of systemic chemotherapy drugs which target specific areas where cancer cells grow. Dr Ranga Rao Rangaraju is one of the best cancer specialist doctors in Delhi NCR. World-Class Cancer treatment facilities. Dr Ranga Rao Rangaraju, the reputed cancer specialist (medical oncologist) in Gurugram. He is extensively trained in management of all cancers with great skills and deals with chemotherapy, hormonal therapy, targeted therapy and the recently introduced immunotherapy.