## Core Concept
The disposal of cytotoxic drugs, especially outdated ones, is crucial for safety and environmental reasons. Cytotoxic drugs are hazardous materials that can pose significant risks to healthcare workers, patients, and the environment if not disposed of properly. Their disposal often requires special handling.

## Why the Correct Answer is Right
Incineration at high temperatures is considered an effective method for disposing of hazardous materials, including cytotoxic drugs. This process involves burning the waste at high temperatures, typically above 1000°C, in the presence of oxygen. This method can effectively destroy the chemical structure of the drugs, rendering them non-hazardous. The high temperature ensures that the cytotoxic drugs are broken down into less harmful substances, reducing the risk of environmental contamination and exposure to toxic substances.

## Why Each Wrong Option is Incorrect
- **Option A:** Simple disposal in a landfill is not suitable for cytotoxic drugs because they can contaminate soil and groundwater, posing long-term environmental and health risks.
- **Option B:** Disposal through a sewer system is not appropriate as it can lead to water pollution, affecting aquatic life and potentially entering the human water supply chain.
- **Option C:** Although recycling or reusing might be ideal for some materials, cytotoxic drugs cannot be safely reused or recycled due to their hazardous nature.

## Clinical Pearl / High-Yield Fact
A key point to remember is that the disposal of hazardous pharmaceutical waste, including cytotoxic drugs, is regulated by specific guidelines and laws that vary by country but often include incineration as a recommended method. Healthcare facilities must adhere to these guidelines to ensure safety and compliance.

## Correct Answer Line
**Correct Answer: D. Incineration.**