From the Guidelines
The 5-year disease-free survival rate for patients with pT3N0 colonic adenocarcinoma with poor differentiation and perineural invasion is approximately 60-70%. This estimate is based on the consideration of high-risk factors such as poor differentiation and perineural invasion, which are known to negatively impact survival outcomes 1. The presence of these factors may lead to the consideration of adjuvant chemotherapy, as suggested by the ASCO guideline update for stage II colon cancer, which recommends that patients with high-risk factors, including poorly differentiated tumor grade and perineural invasion, may be offered adjuvant chemotherapy 1.
The T3 classification indicates that the tumor has grown through the muscularis propria into the pericolorectal tissues, while N0 confirms the absence of regional lymph node metastasis, which is a positive prognostic factor. However, the adverse histological features of poor differentiation and perineural invasion outweigh this positive factor, necessitating a more aggressive treatment approach. Poor differentiation indicates aggressive tumor biology, and perineural invasion is associated with increased local recurrence and distant metastasis.
Given these high-risk pathological features, adjuvant chemotherapy with regimens such as FOLFOX (leucovorin, 5-fluorouracil, and oxaliplatin) for 6 months following surgical resection may be considered to improve survival outcomes, as informed by the ASCO guideline update 1. Key considerations in the decision-making process include the potential benefits of improved 5-year disease-free survival and the rate of adverse events, such as peripheral neuropathy, associated with oxaliplatin-containing chemotherapy 1.
From the Research
Survival Rates for pT3N0 Colonic Adenocarcinoma
- The 5-year free survival rate for patients with pT3N0 colonic adenocarcinoma is not directly stated in the provided studies.
- However, study 2 reports that histological grade III and mucinous histotype were found to impact on cumulative incidence of colon-related events, but does not provide specific survival rates for pT3N0 patients with poor differentiation and perineural invasion.
- Study 3 reports a 5-year overall survival (OS) rate of 83% for stage IIB colon cancer patients, but this study focuses on the impact of adjuvant oxaliplatin and tumor sidedness on OS, and does not provide specific data for pT3N0 patients.
- Studies 4, 5, and 6 do not provide relevant data for pT3N0 colonic adenocarcinoma with poor differentiation and perineural invasion.
Prognostic Factors
- Study 2 identifies histological grade III and mucinous histotype as predictors of worse outcome in pT3N0 colon cancer patients.
- Study 4 reports that tumor depth ≥10 mm was the only independent prognostic factor for 5-year local control, disease-free survival, and disease-specific survival in patients with pT3N0 oral cavity squamous cell carcinoma.
- Perineural invasion is not mentioned as a prognostic factor in the provided studies.
Adjuvant Therapy
- Study 2 reports that adjuvant chemotherapy did not show a significant impact on survival rate in pT3N0 colon cancer patients.
- Study 5 recommends adjuvant oxaliplatin-based chemotherapy for patients with high-risk stage III disease, but does not provide specific guidance for pT3N0 patients with poor differentiation and perineural invasion.
- Study 6 reports that the addition of oxaliplatin to adjuvant chemotherapy provides overall survival benefit for patients with stage III colon cancer, but does not provide specific data for pT3N0 patients.