From the Guidelines
Neoadjuvant chemotherapy is indicated for locally advanced rectal cancer, specifically for T3-T4 tumors or node-positive disease (N+), as it can downstage tumors, reduce local recurrence rates, and improve resectability. The two key elements for staging rectal cancer are MRI of the pelvis and endorectal ultrasound, which help determine the depth of tumor invasion and lymph node involvement 1. Standard neoadjuvant treatment typically consists of long-course chemoradiation with 5-fluorouracil (5-FU) or capecitabine concurrent with radiation (45-50.4 Gy over 5-6 weeks), followed by surgery 6-10 weeks later. Alternatively, short-course radiation therapy (25 Gy over 5 days) followed by surgery within 1 week may be used in select patients. Total neoadjuvant therapy (TNT), which includes both chemoradiation and additional cycles of systemic chemotherapy (typically FOLFOX or CAPOX) before surgery, is increasingly used for high-risk tumors 1.
Some key points to consider when deciding on neoadjuvant chemotherapy for rectal cancer include:
- The patient's overall health status and tumor characteristics
- The risk of local recurrence and distant metastases
- The potential benefits of downstaging tumors and improving resectability
- The potential risks and side effects of neoadjuvant chemotherapy and radiation therapy
According to the most recent guidelines, total neoadjuvant therapy (TNT) is recommended for patients with high-risk locally advanced rectal cancer 1. Additionally, chemotherapy with neoadjuvant fluorouracil, leucovorin, and oxaliplatin (FOLFOX) and selective CRT is recommended for patients with lower risk locally advanced rectal cancer 1. The decision for neoadjuvant therapy should be made in a multidisciplinary tumor board setting, considering the patient's individual needs and circumstances 1.
From the Research
Indications for Neoadjuvant Chemotherapy in Rectal Cancer
The indications for neoadjuvant chemotherapy in rectal cancer are based on the stage and location of the tumor.
- Stage II and III rectal cancers are typically considered for neoadjuvant chemotherapy, as they have a higher risk of local recurrence and distant metastasis 2.
- Neoadjuvant chemotherapy can be used to downstage the tumor, making it more likely that sphincter-sparing surgery can be performed 3.
- The use of neoadjuvant chemotherapy alone, without radiation therapy, is being explored as an alternative to chemoradiotherapy in locally advanced rectal cancer 4, 5.
Staging for Rectal Cancer
Two important things for staging rectal cancer are:
- The depth of tumor invasion (T stage)
- The presence or absence of lymph node metastasis (N stage)
Neoadjuvant Chemotherapy Regimens
Different chemotherapy regimens have been studied for use in neoadjuvant therapy for rectal cancer, including:
- Fluoropyrimidine-based regimens, such as 5-FU or capecitabine, with or without oxaliplatin 6, 3.
- Combination regimens, such as FOLFOX (fluorouracil, leucovorin, and oxaliplatin) with or without bevacizumab 4.
- The choice of regimen depends on the individual patient's disease characteristics and overall health.