Final answer:
Chemotherapy causes systemic toxicities affecting rapidly dividing cells, leading to side effects like nausea and vomiting due to gastrointestinal damage. Mucositis, an inflammation of mucous membranes, arises because chemotherapy hampers cell regeneration in the digestive tract. The lack of drug specificity and potential for resistance necessitates the use of combination chemotherapy.
Step-by-step explanation:
Chemotherapy causes several types of systemic toxicities because it targets cells that are rapidly dividing. This is not specific only to cancerous cells but also affects healthy cells within the body that naturally have a high turnover, such as those in the skin, hair, gastrointestinal tract, and bone marrow. This non-specific action is why we see side effects like nausea and vomiting (N/V), which are triggered by the damage chemotherapy causes to the cells lining the gastrointestinal tract. The brain's chemoreceptor trigger zone (CTZ) is stimulated by these injured cells, which then activates the vomiting center to produce N/V.
Mucositis is an inflammation and ulceration condition that can occur along the entire digestive tract but is most commonly seen in the oral cavity as painful swelling, redness, and ulceration of the mucous membranes. This occurs because chemotherapy drugs hinder the regeneration of rapidly dividing mucosal cells. Replenishment of these cells is crucial for maintaining the integrity of the mucosal lining, and when these cells are affected by chemotherapy, mucositis can develop, leading to discomfort and an increased risk of infection.
The therapeutic aim of anticancer drugs is to reduce the growth of cancer cells; however, the lack of specificity means that normal cells are also harmed. This is further complicated by the potential for certain cancer cells to develop resistance to these drugs, making combination chemotherapy regimes using multiple drugs necessary for treatment efficacy. The impact on the rapidly dividing cells of the hair follicles, digestive system lining, and hematopoietic stem cells in bone marrow explains the common side effects associated with chemotherapy treatments.