A 58-year-old woman presents to the Emergency Department with profound fatigue, mucositis, and profuse diarrhoea. She completed her last cycle of combination chemotherapy for breast cancer five weeks ago. On arrival she appears dehydrated and febrile with tachycardia. Her blood tests show neutropenia and rising creatinine.

The triage nurse reports she last contacted the oncology helpline three weeks ago due to mild nausea, which was managed at home.

You suspect severe systemic anti-cancer therapy (SACT) toxicity.

According to national guidance,toxicities from cytotoxic chemotherapy can occur up to how long after the last treatment is administered?