Treatment of Colorectal cancer
Different modalities to treat colorectal cancer include:
- Targeted therapy
These are used alone or in combination depending on the stage of the cancer, performance status of the patient, grade of the tumor and other factors.
Stage-wise treatment of colorectal cancer:
Treatment of colorectal cancer depends on the stage of the cancer.
Stage 0 colon/rectal cancer
Removal of a polyp which is called polypectomy, during the colonoscopy procedure is the treatment at this stage. If the polyp is not excised completely, additional surgery may be required. Rarely removing a part of the colon which is called partial colectomy may be required if a tumor is too big to be removed by local excision.
Stage I colon/rectal cancer
Surgical removal of the tumor and lymph nodes is usually the only treatment needed.
Partial colectomy- surgery to remove the section of colon that has cancer and nearby lymph nodes is the standard treatment. Additional treatment is usually not required.
Stage II colon/rectal cancer
Partial colectomy -surgery to remove the section of colon that has cancer and nearby lymph nodes is the standard treatment. Additional treatment in the form of chemotherapy or radiotherapy is indicated in certain conditions like: high grade tumor, high CEA (carcinoembryonic antigen) levels >5 ng/ml, if fewer than 12 lymph nodes are removed and examined and if the tumor had caused obstruction or perforation of the colon before surgery.
The various chemotherapy regimens used in treatment of colorectal cancer are given below.
Stage III colon/rectal cancer
Treatment usually involves surgical removal of the tumor followed by adjuvant chemotherapy. Patients with rectal cancer, radiation therapy may be used along with chemotherapy before or after surgery along with adjuvant chemotherapy.
Stage IV colon cancer
In this stage, surgery is not possible in majority of the cases considering the metastasis of the disease. However if the size of the metastasis is small and is excisable, surgery may be planned in such cases at the discretion of the surgeon.
Operations such as diverting colostomy may be required in patients with obstructed colon or perforated colon. In this procedure, the colon is cut above the level of the cancer and the end is attached to an opening in the skin on the abdomen to allow waste out.
CHEMOTHERAPY REGIMENS USED IN COLORECTAL CANCER
Some common treatment regimens include:
- 5-Flurouracil (5-FU)
- 5-FU with leucovorin
- Capecitabine which is an oral form of 5-FU
- 5-FU with leucovorin and oxaliplatin (FOLFOX)
- 5-FU with leucovorin and irinotecan (FOLFIRI)
- Irinotecan alone
- Capecitabine with either irinotecan or oxaliplatin
- Any of the above with either cetuximab, bevacizumab, or panitumumab
- FOLFIRI with ziv-aflibercept or ramucirumab
- Regorafenib alone
TARGETED THERAPY IN THE TREATMENT OF COLORECTAL CANCER
Targeted therapy targets the cancer’s specific genes, proteins, or the tissue environment that contributes to cancer growth and survival. Targeted therapy blocks the growth and spread of cancer cells while limiting damage to healthy cells.
Types of targeted therapy
It acts by stopping angiogenesis, which is the process of making new blood vessels. Few examples in this group include Bevacizumab, Ziv-aflibercept, Ramucirumab etc.
- Epidermal growth factor receptor (EGFR) inhibitors.
It acts by inhibiting the epidermal growth factor receptor. This may be effective for stopping or slowing the growth of colorectal cancer. Cetuximab, Panitumumab belong to this group of targeted therapy.