Topical Tazarotene Vs Placebo In Hand-Foot-Skin Reactions

Inclusion Criteria: * Participants must have histologically or cytologically confirmed solid tumors with a plan to initiate regorafenib, or having started regorafenib in the last 48 hours, via dose escalation protocol describe in the ReDOS study in CRC. The ReDOS study recommends this dose escalation of regorafenib:80mg daily x 1 week, 120mg daily x 1 week, 160mg daily times one week, off week, then 160mg daily goal, or maximum tolerated dose thereafter. This is not a separate study; this is the current standard of care for regorafenib dosing. In addition, to compare across the cohorts, patients must be ambulatory with full use of all 4 distal extremities. * Age ≥ 18 * ECOG performance status ≤2 (Karnofsky ≥60%, see Appendix A) * Participants must have sufficient organ and marrow function in the opinion of the treating investigator. This can be based on lab reports from an outside facility. * Women of child-bearing potential (WOCBP) and men must agree to use adequate contraception (hormonal or barrier method of birth control; abstinence) prior to study entry and for the duration of study participation Tazarotene is known to be teratogenic, although the dose required with topical application to affect the developing human fetus is unknown. Should a woman become pregnant or suspect she is pregnant while she or her partner is participating in this study, she should inform her treating physician immediately. Men treated or enrolled on this protocol must also agree to use adequat…