What is the treatment for Stage T3 (Tumor invading through the muscularis propria into perirectal tissue) rectal cancer?

From the Guidelines

Treatment for T3 rectal cancer should involve a multimodal approach combining neoadjuvant chemoradiation therapy, total mesorectal excision (TME) surgery, and adjuvant chemotherapy to minimize the risk of local recurrence and distant metastasis, as recommended by the most recent guidelines 1. The standard treatment begins with neoadjuvant (pre-surgical) chemoradiation therapy, usually consisting of 5-fluorouracil (5-FU) or capecitabine administered concurrently with radiation therapy over 5-6 weeks. Some key points to consider in the treatment of T3 rectal cancer include:

• The use of preoperative chemoradiotherapy as the standard treatment for locally advanced mid-low rectal cancer (stage II, III) 1
• The importance of total neoadjuvant therapy (TNT) approach, which includes concurrent chemoradiotherapy followed by sequential systemic chemotherapy, to enhance tumor regression and improve pathological complete response (pCR) rates 1
• The recommendation to start postoperative adjuvant treatment as early as possible, and no later than 8 weeks after surgery, with a total treatment duration of 6 months 1
• The consideration of a "watch and wait" strategy for patients achieving clinical complete response (cCR) based on digital rectal examination (DRE), rectal MRI, and direct endoscopic evaluation, which should be conducted in experienced multidisciplinary centers 1 The surgical approach may be either low anterior resection with anastomosis or abdominoperineal resection depending on tumor location. After surgery, adjuvant chemotherapy is typically recommended for 4-6 months, often using FOLFOX (5-FU, leucovorin, and oxaliplatin) or CAPOX (capecitabine plus oxaliplatin) regimens. This comprehensive approach is necessary because T3 rectal cancer has penetrated through the muscularis propria into the perirectal tissues, increasing the risk of local recurrence and distant metastasis, as noted in previous guidelines 1. The neoadjuvant therapy helps downstage the tumor before surgery, while adjuvant chemotherapy addresses potential micrometastatic disease. Regular follow-up with physical examinations, CEA testing, and imaging studies is essential for monitoring recurrence for at least 5 years after treatment completion.

From the Research

Treatment Options for T3 Rectal Cancer

• The treatment of T3 rectal cancer often involves a combination of chemotherapy, radiation therapy, and surgery 2, 3, 4, 5.
• Neoadjuvant chemoradiation has become a widely accepted strategy for treating locally advanced rectal cancer, including T3 tumors 2, 3.
• Studies have shown that the addition of oxaliplatin to the neoadjuvant chemoradiation regimen may benefit T3+ and T4 rectal cancer patients 5.
• Transanal excision after neoadjuvant chemoradiation is a safe alternative to radical resection in a highly select group of patients with T2 and T3 rectal cancers 4.

Chemoradiation Regimens

• Different chemoradiation regimens have been used, including capecitabine and oxaliplatin (CORE), capecitabine only (CAP), and 5-FU and leucovorin (5FUBolus) 5.
• The CORE scheme has been shown to be the most effective regimen for locally advanced rectal cancer tumors, with better downstaging and resectability rates 5.

Personalized Treatment Approach

• Recent studies suggest that not all T3 rectal cancer patients may benefit from preoperative radiotherapy, and a subset of patients with good prognosis may be treated with surgery alone 6.
• The rationale for selecting good prognosis T3 rectal cancer for surgery alone is based on the broad range of prognosis within T3 rectal cancer and the potential for overtreatment with long-term toxicity related to radiotherapy 6.