Standard palliative radiotherapy regimens may provide limited durability of response in large tumors. Thus, there is a clinical need for a new approach. The Lattice SBRT approach will deliver 20 Gy in 5 fractions with partial volume simultaneous integrated boosts to 66.7 Gy. This is hypothesized to improve symptom response, local control, and better prime the tumor microenvironment for immune response compared with standard palliative radiotherapy doses. It is also hypothesized that this will be associated with less toxicity than the traditional homogenous SBRT plan delivered to a large tumor. Blood will be collected before and after Lattice SBRT for evaluation of the peripheral blood immune microenvironment.

Inclusion Criteria:

• Histologically or cytologically confirmed cancer.
• Planning to undergo palliative radiotherapy to a lesion ≥ 4.5 cm as measured with radiographic imaging or with calipers by clinical exam.
• ECOG performance status ≤ 2
• At least 18 years of age.
• Radiotherapy is known to be teratogenic. For this reason, women of childbearing potential 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. Should a woman become pregnant or suspect she is pregnant while participating in this study, she must inform her treating physician immediately. Men treated or enrolled on this protocol must also agree to use adequate contraception prior to the study, for the duration of the study, and 6 months after completion of the study
• Ability to understand and willingness to sign an IRB approved written informed consent document (or that of legally authorized representative, if applicable).

Exclusion Criteria:

• Prior radiotherapy that overlaps with any planned site of protocol radiotherapy.

• Patients with tumors in need of urgent surgical intervention, such as life-threatening bleeding or those at high risk for pathologic fracture.

• Currently receiving any cytotoxic cancer therapy regimens or VEGF inhibitors that will overlap with the Lattice SBRT administration.

  *Cytotoxic chemotherapy and VEGF inhibitors prior to radiotherapy or planned after radiotherapy delivery are allowed at the discretion of the treating radiation oncologist. This includes continuing a treatment plan which was initiated prior to the start of radiotherapy. A 2 week washout is recommended, but not required.

• Pregnant and/or breastfeeding. Women of childbearing potential must have a negative pregnancy test within 20 days of study entry.

• Patients with HIV are eligible unless their CD4+ T-cell counts are < 350 cells/mcL or they have a history of AIDS-defining opportunistic infection within the 12 months prior to registration. Concurrent treatment with effective ART according to DHHS treatment guidelines is recommended. Recommend exclusion of specific ART agents based on predicted drug-drug interactions (i.e. for sensitive CYP3A4 substrates, concurrent strong CYP3A4 inhibitors (ritonavir and cobicistat) or inducers (efavirenz) should be contraindicated).

Adverse events were collected from start of treatment through 90 days following completion of treatment.