The debate for thermal ablation of colorectal cancer pulmonary metastases is heating up

Abstract

Colorectal cancer (CRC) is the third most common cancer worldwide and the fourth most common cause of cancer death. The number of deaths is expected to rise in all countries until 2035, for both colon and rectal cancer by 60% and 71% respectively, mainly due to population growth and ageing (1). The highest CRC incidence rates are in Australia, New Zealand, Europe, and North America, and the lowest rates are found in Africa and South-Central Asia. These geographic differences appear to be attributable to differences in socioeconomic status, and to dietary and environmental exposures imposed upon a background of genetically determined susceptibility (2).Death from CRC is usually a result of metastatic spread. Lung is the second most common site for metachronous CRC metastatic spread, liver being the first. About 20% of patients present with synchronous metastases, most commonly in the liver, and up to 60% of the remaining patients develop metastases within 5 years (3). Rectal cancer and left-sided colon cancer are associated with significantly higher rates of lung-only metastases, seen in 10-20% of patients (4,5). The prognosis of untreated stage IV disease is poor, with an average lifespan of 5-6 months (4). There is extensive data showing survival benefit for metastasectomy for CRC lung metastases, favourable factors being a maximum of 3 metastases, unilateral lesions, lack of thoracic nodal involvement, long disease-free interval (DFI) and no elevated carcinoembryonic antigen (CEA) pre thoracotomy (6). A history of resected liver metastases did not reach statistical significance for poorer outcome, provided there was no evidence of hepatic metastatic involvement at the time of pulmonary metastasectomy (6).Disease recurrence is common after pulmonary metastasectomy-with 69% of patients showing new metastases in lung, liver or both; repeat resection carries a better survival than other treatments or palliative care (7,8). The addition of targeted therapy to conventional chemotherapy has been a recent valuable adjunct to the neoadjuvant or adjuvant treatment of the primary colorectal site. However, pulmonary metastases do not respond well to chemotherapy (9).Recent data on stereotactic body radiation therapy (SBRT) of pulmonary oligometastatic disease shows a significantly lower local control rate for CRC primaries compared to other primary sites with 24-month cumulative incidence rates of local failure above 40% (10-12).Heat based thermal ablation for both primary and secondary lung malignancies has been performed since

Curative‐intent treatment of pulmonary metastases from colorectal cancer: A comparison between imaging‐guided thermal ablation and surgery

“…24 Regards RFA, DFI <12 months, elevated CEA level, absence of neoadjuvant chemotherapy, uncontrolled extra-PM, PM >2 cm, and number of PM >3 were poor prognostic factors for OS. 13,25,26 Unfortunately, our study failed to confirm these prognosis factors for both OS and PFS.…”

“…Poor prognosis factors associated with PM resection are elevated CEA level, short DFI, multiple PM, and chest lymph nodes involvement 24 . Regards RFA, DFI <12 months, elevated CEA level, absence of neoadjuvant chemotherapy, uncontrolled extra‐PM, PM >2 cm, and number of PM >3 were poor prognostic factors for OS 13,25,26 . Unfortunately, our study failed to confirm these prognosis factors for both OS and PFS.…”