Does a 53-year-old female patient with a pathological stage of pT3N0M0 (American Joint Committee on Cancer (AJCC) 8th edition) moderately differentiated adenocarcinoma (Grade 2) of the sigmoid colon require adjuvant chemotherapy?

From the Guidelines

Based on the pathological findings of a pT3N0M0 moderately differentiated sigmoid colon adenocarcinoma, adjuvant chemotherapy may be considered for this patient, but the decision should be individualized and based on a discussion of the benefits and risks of chemotherapy, considering the patient's age, performance status, and comorbidities. The patient's tumor has several high-risk features, including a large size (9 cm), proximity to the serosal surface (within 2 mm), and the presence of a mucinous component (~15-20%) [ 1 ]. However, the absence of lymphovascular invasion and low tumor budding score are favorable factors. The preferred regimen for adjuvant chemotherapy in stage II colon cancer is not well established, but options include 5-fluorouracil (5-FU)/leucovorin (LV) or capecitabine, with or without oxaliplatin [ 1 ]. A medical oncology consultation should be arranged promptly to discuss the benefits versus risks of chemotherapy and determine the best course of treatment for this patient. Some studies suggest that adjuvant chemotherapy may be beneficial in reducing recurrence risk by approximately 10-15% in patients with stage II colon cancer [ 1 ]. However, the decision to administer adjuvant chemotherapy should be based on a comprehensive evaluation of the patient's individual risk factors and overall health status [ 1 ]. In this case, the patient's age, performance status, and comorbidities should be carefully considered when making a decision about adjuvant chemotherapy. Ultimately, the decision to administer adjuvant chemotherapy should be made on a case-by-case basis, taking into account the patient's unique characteristics and the potential benefits and risks of treatment.

From the FDA Drug Label

The efficacy of oxaliplatin in combination with fluorouracil (FU)/leucovorin (LV) was evaluated in an international, multicenter, randomized (1:1) trial (The Multicenter International Study of Oxaliplatin/5-Fluorouracil/Leucovorin in the Adjuvant Treatment of Colon Cancer [MOSAIC], NCT00275210) in patients with stage II (Dukes' B2) or III (Dukes' C) colon cancer who had undergone complete resection of the primary tumor.

Eligible patients were between 18 and 75 years of age, had histologically proven stage II (T3 to T4 N0 M0; Dukes' B2) or III (any T N1-2 M0; Dukes' C) colon carcinoma

In the overall and the stage III colon cancer populations, DFS was statistically significantly improved in the oxaliplatin-containing arm compared to fluorouracil/leucovorin alone; however, a statistically significant improvement in DFS was not observed in Stage II patients.

The patient has pT3N0M0 disease, which corresponds to Stage II (Dukes' B2) colon cancer. According to the study, there was no statistically significant improvement in DFS with the addition of oxaliplatin in Stage II patients. Therefore, based on this information, adjuvant chemotherapy with oxaliplatin may not be necessary for this patient 2.

From the Research

Patient Information and Diagnosis

• The patient is a 53-year-old female with a known case of sigmoid colon mass.
• She underwent an extended sigmoidectomy, and the specimens submitted included distal and proximal resection donut margins and the sigmoid colon mass.
• The diagnosis is moderately differentiated adenocarcinoma (Grade 2) with a focal mucinous component (~15–20%).
• The tumor invasion is through the muscularis propria into pericolonic adipose tissue.
• All surgical margins are free of tumor, with the closest margins being proximal = 15 cm, distal = 8 cm, and serosal = within 2 mm.
• No lymphovascular or perineural invasion, tumor deposits, or distant metastasis were found.

Staging and Prognosis

• The final pathologic stage is pT3N0M0.
• The patient's tumor is classified as stage II colon cancer, which is considered high-risk due to the tumor's invasion through the muscularis propria and its proximity to the serosal surface.
• Studies have shown that adjuvant chemotherapy may improve prognosis in patients with high-risk stage II colon cancer, particularly those with lymphovascular invasion or other high-risk features 3.
• However, the patient in this case does not have lymphovascular invasion, which is a key factor in determining the need for adjuvant chemotherapy.

Adjuvant Chemotherapy

• The decision to administer adjuvant chemotherapy depends on various factors, including the patient's overall health, tumor characteristics, and the presence of high-risk features.
• Studies have shown that adjuvant chemotherapy can improve overall survival and disease-free survival in patients with high-risk stage II colon cancer, but the benefit is not uniform and depends on individual patient characteristics 3, 4.
• In this case, the patient's tumor is moderately differentiated, and there is no lymphovascular invasion or other high-risk features.
• Based on the available evidence, it is unclear whether adjuvant chemotherapy would provide a significant benefit for this patient, and the decision should be made on a case-by-case basis, taking into account the patient's individual characteristics and preferences 5, 6, 7.