Prophylactic Antiviral Therapy in Patients With Current or Past Hepatitis B Virus Infection Receiving Anti-Cancer Therapy for Solid Tumors

Inclusion Criteria:

* Patients must be diagnosed with stage I-III solid tumor malignancy; patients with only carcinoma in situ or with stage IV disease are excluded
* Patients must not have lymphoma, leukemia, or myeloma
* Patients must not have primary liver cancer, known cirrhosis, or evidence of any malignancy that involves the liver
* Patients must be planning to receive systemic anti-cancer therapy (either single agent or some combination of systemic cytotoxic therapy, systemic immunotherapy or systemic targeted therapy) for this solid tumor
* Patients must not have been previously treated with the same anti-cancer therapy regimen that is now anticipated; the anti-cancer therapy does not have to be first-line therapy; prior and/or concurrent radiotherapy is allowed
* Patients must be registered \<= 28 days prior to the planned start date of anti-cancer therapy; if the patient has started systemic anti-cancer therapy, patient must be registered \<= 42 days after the initiation of first cycle of anti-cancer therapy
* Patients who have received prior anti-cancer therapy must have discontinued all previous therapies (excluding planned anti-cancer therapy to occur in conjunction with this study) \>= 1 day prior to registration to this study
* Patients must not have had any cancer therapy regimen that includes anti-CD20
* Patients must not be receiving antiviral medications active against HBV, including: adefovir, entecavir, lamivudine, telbivudine, tenofovir disoproxil fumarate, tenofovir alafenamide (TAF), or any other Food and Drug Administration (FDA) approved agents for the treatment of hepatitis B; patients who have previously received antiviral medication must not have required any antiviral medication active against HBV \>= 90 days prior to registration to this study
* Patients must not have had hematopoietic stem cell transplantation therapy
* Patients must not be taking or planning to take warfarin
* Patients who will be treated with TAF must not be taking or planning to take oxcarbazepine, phenobarbital, phenytoin, rifabutin, rifampin, rifapentine, or St. John's Wort
* Patients who will be treated with TAF and are concomitantly taking or plan to take carbamazepine must be given an increased dose of TAF or alternatively be given ETV or TDF
* Patients must have results for the following HBV tests done within 28 days prior to registration: HBsAg AND anti-HBc (total immunoglobulin \[Ig\] or IgG, but not IgM only) AND hepatitis B surface antibody (anti-HBs); for the anti-HBs test, quantitative or qualitative (including "indeterminate") results are allowable
* Patients must have tested positive for HBsAg or anti-HBc (total Ig, IgG, but not IgM) and must have baseline HBV deoxyribonucleic acid (DNA) completed \<= 42 days prior to registration
* Complete blood count (CBC) must be completed \<= 28 days prior to registration; results do not need to be in the institutional limits of normal
* International normalized ratio (INR) must be completed \<= 28 days prior to registration; results must \<= 1.2 x institutional limits of normal
* Alanine aminotransferase (ALT) must be obtained \<= 28 days prior to registration; ALT must be \< 1.5 x institutional ULN
* Total bilirubin must be obtained \<= 28 days prior to registration; total bilirubin must be \< 1.5 x institutional ULN
* Creatinine results must be obtained \<= 28 days prior to registration
* Patients must not have known current active hepatitis C infection (HCV); active HCV is defined by a detectable HCV ribonucleic acid (RNA) level; Note: HCV testing is not required for eligibility
* Patients must not have a history of human immunodeficiency (HIV) infection; patients with unknown HIV status must have HIV testing completed \<= 365 days prior to registration
* Patients must have Zubrod performance status of 0-2
* Patients must not be pregnant or nursing, as the safety of the study drug in pregnant and nursing women has not been established; women/men of reproductive potential must have agreed to use an effective contraceptive method; a woman is considered to be of "reproductive potential" if she has had menses at any time in the preceding 12 consecutive months; in addition to routine contraceptive methods, "effective contraception" also includes heterosexual celibacy and surgery intended to prevent pregnancy (or with a side-effect of pregnancy prevention) defined as a hysterectomy, bilateral oophorectomy or bilateral tubal ligation; however, if at any point a previously celibate patient chooses to become heterosexually active during the time period for use of contraceptive measures outlined in the protocol, he/she is responsible for beginning contraceptive measures
* Patients must have specimens collected for submission as outlined
* Patients must be offered the opportunity to participate in optional translational medicine studies as outlined
* Patients with impaired decision-making capacity are eligible as long as their neurological or psychological condition does not preclude their safe participation in the study (e.g., tracking pill consumption and reporting adverse events to the investigator)
* Patients may have concurrent participation in other clinical trials that entail cytotoxic, immunotherapy, targeted therapy; surgical treatment; radiotherapy treatment; or any combination thereof
* Patients must be informed of the investigational nature of this study and must sign and give written informed consent in accordance with institutional and federal guidelines
* As a part of the Oncology Patient Enrollment Network (OPEN) registration process the treating institution's identity is provided in order to ensure that the current (within 365 days) date of institutional review board approval for this study has been entered in the system