Should I decline to treat a patient with a first site of metastasis who refuses a biopsy?

Ideally, all patients with a first site of metastatic disease should have a biopsy. However, the details are critical. Is the location amenable to a bx? Is the patient's performance status poor? Has it been an extended period of time since treatment for the primary disease? Is it a solitary metastasis, or are there metastases everywhere? Will the biopsy determine the recommend course of treatment (EGFR, ER, ALK1, ...)? These questions and others will determine the importance of a biopsy.