Table 2. Routes of delivery of oncolytic viruses: advantages, disadvantages, and tumors in which routed.

 OV: oncolytic virus, CNS: central nervous system, BBB: blood-brain barrier, LSCC: lung squamous cell carcinoma, GI: gastrointestinal

	Intertumoral route	Intravenous route	Intraperitoneal route	intrathecal route
Advantages	Higher concentration of OV in tumor site. Ability to control desirable concentration.	Good option in case of inaccessible tumors. Convenient and rapid.	Faster absorption. Relatively easy to be administrated. Targeting abdominal cavity organs.	Ideal for CNS tumors.
Disadvantages	Challenges in access deeper tumors. Difficult repeating doses in complex procedures.	Requires highly selective targets. Physiological barriers (e.g., BBB) and elimination by immune response. More toxicity.	Slower absorption than IV.	Limited to CNS.
Tumors	Melanoma Retinoblastoma Pancreatic carcinoma Astrocytoma Gliomas Breast cancer Colorectal cancer	Melanoma. Bladder cancer. LSCC Astrocytoma. Neuroblastoma. Ovarian cancer. Prostatic carcinoma. Glioblastoma	Angiosarcoma. Epithelioid sarcoma. Kaposi’s sarcoma. GI stromal cancer. Leiomyosarcoma. Liposarcoma. Pancreatic carcinoma	Glioblastoma. Glioma. Ependymoma. Primitive neuroectodermal tumor. CNS lymphoma