Under what circumstances, if any, do you offer treatment holidays when treating patients with metastatic HER2+ breast cancer?

Under what circumstances, if any, do you offer treatment holidays when treating patients with metastatic HER2+ breast cancer?

• I never offer treatment holidays
• I offer treatment holidays if cumulative toxicity develops
• I offer treatment holidays if Stage IV NED after oligometastatic definitive treatment
• I offer treatment holidays if the patient maintains a CR for prolonged period of time
• Other