Chemotherapy for Colorectal Cancer

Of the many cancer treatments available, chemotherapy is known for its prominent side effects. Despite this, chemotherapy remains an important and effective treatment for colorectal cancer. Being prepared for its potential side effects is crucial and can help you better mentally and physically prepare for each treatment cycle.

Often called ‘chemo’ for short, chemotherapy relies on the use of drugs to kill cancerous cells and prevent them from growing and spreading to other parts of the body. More specifically, chemotherapy drugs are usually non-specific drugs that target cells undergoing cell division and disrupt the process by damaging cellular DNA. When irreparable DNA damage is sustained, the cells enter programmed cell death or apoptosis.

While there are different methods for chemo drugs to be administered, such as through oral medication or through infusion via a skin patch, colorectal cancer chemo drugs are usually injected intravenously, i.e. into a vein. The injection can be done over a few minutes or through an IV over a longer period of time. When the drugs are injected through the vein, it travels through the bloodstream to reach dividing cells throughout the body, and is thus referred to as systemic chemotherapy.

Regional chemotherapy, on the other hand, is more targeted as the name suggests. This involves injecting the chemotherapy drug into an artery instead, so that the drug is carried towards the target organ where the cancer is localized and can minimize the reach and consequently the harmful effects of the drug on the rest of the body.

Chemotherapy can be administered at different stages of a patient’s cancer journey. At times when the tumors are large, neoadjuvant chemotherapy before the primary treatment is given with the objective of reducing the size of the tumor. This helps maximize the effectiveness of the primary treatment, which can come in the form of surgery, immunotherapy, targeted therapy, or other treatments.

Following the primary treatment to remove any detectable cancer, adjuvant chemotherapy is sometimes administered to eliminate any remaining cancer in the body and reduce the chance of relapse.

In advanced cancer, chemotherapy is sometimes used to treat a patient who suffers from metastasized cancer. While the treatment may not be able to completely remove the cancer, it may help to prolong life as well as improve quality of life.

Chemotherapy is also typically administered in cycles. These cycles can vary; in some cases, only one dose of the drug is given at the start of the cycle. In other instances, the drug could be given a few days in a row. A rest period usually follows to allow time for the body to recover from the drug’s side effects.

At the moment, different drugs have been approved for use by the US FDA. These include:

• Capecitabine
• Fluorouracil
• Irinotecan
• Folinic acid
• Oxaliplatin
• Trifluridine and Tipiracil Hydrochloride

These drugs are used to treat different stages of colorectal cancer, and are sometimes used in the treatment of other cancers as well. Many of these are administered on their own, while others may be used in combination to treat colorectal cancer in different ways.

Because chemotherapy drugs do not specifically target cancer cells and instead target cells that are dividing, this also means that normal healthy cells in the body that are undergoing cell division are susceptible to the effects of the drugs. This is the main reason why many cancer patients undergoing chemo experience alopecia or hair loss, as the healthy, but rapidly-dividing hair follicle cells are killed as a result of the drug.

Chemotherapy can also impact the immune system when it affects blood stem cells in the bone marrow. This can lead to:

• Poor immunity and increased susceptibility to infections due to a low white blood cell count
• Anemia and fatigue due to low red blood cell count
• Easy bruising and bleeding due to low platelet count

Chemotherapy can also cause other side effects, including mouth sores, nausea and vomiting, weight loss due to loss of appetite, diarrhea, nail and skin changes.

Before embarking on your cancer treatment, ensure to speak with your doctors regarding the plan that is best suited for your needs. Seek a second opinion if you are unsure about the recommended treatment plan. Enlist the support of your loved ones and rely on resources offered by your healthcare providers, as the journey can be challenging to the mind and body. Staying informed about the chemotherapy process and its side effects may help you maintain a sense of control throughout the treatment.