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The role of CT imaging in predicting neoadjuvant chemotherapy requirement in right colon cancer : a critical analysis
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O cancro colorretal (CCR) é uma das neoplasias malignas com maior incidência no mundo inteiro e acarreta uma elevada morbimortalidade. O cólon direito é responsável por aproximadamente um terço dos casos de CCR.
O tratamento standard do cancro do cólon localizado consiste na realização de cirurgia radical complementada com quimioterapia adjuvante se doença de estadios III ou II de alto risco. Recentemente, o estudo FOxTROT demonstrou um benefício significativo associado à realização de quimioterapia neoadjuvante (QTna) em tumores T4 e/ou N+, nomeadamente a redução de 28% da recorrência aos 2 anos.
A seleção de doentes para QTna é realizada com base no estadiamento clínico, obtido por Tomografia Computorizada (TC). No entanto, tem-se verificado grande variabilidade da sua performance na identificação de fatores tumorais de mau prognóstico, critérios para QTna. Adicionalmente, têm surgido preocupações quanto ao risco de overtreatment de tumores de baixo risco quando sobre-estadiados imagiologicamente.
Neste contexto, este estudo tem por objetivos analisar a performance da TC no estadiamento do cancro do cólon direito localizado e avaliar situações de over- e undertreatment em caso de realização de QTna em função do estadiamento obtido.
Os resultados demonstram baixa sensibilidade (26%), mas considerável especificidade (91%), da TC na deteção de tumores pT4, com tendência para o sub-estadiamento do parâmetro T. Relativamente ao parâmetro N, verifica-se considerável sensibilidade (87%) e baixa especificidade (45%).
Quando analisados os parâmetros locorregionais em conjunto, verifica-se que em apenas 57% dos tumores cT4 e/ou cN+ se confirma a presença de pelo menos um fator patológico desfavorável. A aplicação de QTna a todos os doentes definidos clinicamente como de alto risco associa-se a um risco inevitável de overtreatment de 43% dos casos. Dado que a TC continua a ser o método gold standard para estadiamento destes tumores, a decisão sobre realização de QTna deve ser feita com cautela.
Colorectal cancer (CRC) is one of the most common malignant neoplasms worldwide, resulting in high morbidity and mortality rates. The right colon accounts for approximately one-third of CRC cases. The standard treatment for localized colon cancer involves radical surgery, supplemented by adjuvant chemotherapy for stage III or high-risk stage II disease. Recently, the FOxTROT study demonstrated a significant benefit associated with neoadjuvant chemotherapy (NAC) in T4 and/or N+ tumours, particularly a 28% reduction in 2-year recurrence. The selection of patients for NAC is based on clinical staging obtained through Computed Tomography (CT). However, significant variability has been observed in CT's performance in identifying poor prognostic tumour factors, which are criteria for NAC. Additionally, concerns have arisen regarding the risk of overtreatment of low-risk tumours when overstaged by imaging. In this context, this study aims to analyse CT's performance in staging localised right colon cancer and evaluate over- and undertreatment when NAC is administered based on the obtained staging. The results demonstrate low sensitivity (26%) but considerable specificity (91%) of CT in detecting pT4 tumours, with a tendency towards understaging the T parameter. For the N parameter, considerable sensitivity (87%) and low specificity (45%) are observed. When local and regional parameters are analysed together, only 57% of cT4 and/or cN+ tumours confirm the presence of at least one unfavourable pathological factor. Applying NAC to all clinically high-risk patients is associated with an inevitable overtreatment risk in 43% of cases. Given that CT remains the gold standard method for staging these tumours, the decision to apply NAC should be made cautiously.
Colorectal cancer (CRC) is one of the most common malignant neoplasms worldwide, resulting in high morbidity and mortality rates. The right colon accounts for approximately one-third of CRC cases. The standard treatment for localized colon cancer involves radical surgery, supplemented by adjuvant chemotherapy for stage III or high-risk stage II disease. Recently, the FOxTROT study demonstrated a significant benefit associated with neoadjuvant chemotherapy (NAC) in T4 and/or N+ tumours, particularly a 28% reduction in 2-year recurrence. The selection of patients for NAC is based on clinical staging obtained through Computed Tomography (CT). However, significant variability has been observed in CT's performance in identifying poor prognostic tumour factors, which are criteria for NAC. Additionally, concerns have arisen regarding the risk of overtreatment of low-risk tumours when overstaged by imaging. In this context, this study aims to analyse CT's performance in staging localised right colon cancer and evaluate over- and undertreatment when NAC is administered based on the obtained staging. The results demonstrate low sensitivity (26%) but considerable specificity (91%) of CT in detecting pT4 tumours, with a tendency towards understaging the T parameter. For the N parameter, considerable sensitivity (87%) and low specificity (45%) are observed. When local and regional parameters are analysed together, only 57% of cT4 and/or cN+ tumours confirm the presence of at least one unfavourable pathological factor. Applying NAC to all clinically high-risk patients is associated with an inevitable overtreatment risk in 43% of cases. Given that CT remains the gold standard method for staging these tumours, the decision to apply NAC should be made cautiously.
Descrição
Trabalho Final do Curso de Mestrado Integrado em Medicina, Faculdade de Medicina, Universidade de Lisboa, 2024
Palavras-chave
Neoplasias do cólon Overtreatment Performance diagnóstica Quimioterapia neoadjuvante Tomografia computadorizada por raios X