Various homogeneous and heterogeneous factors influence the risk for lung metastasis development and survival outcomes in patients with colorectal cancer (CRC), according to study findings published in BMC Gastroenterology.
Researchers acquired open public data from the US National Cancer Institute’s Surveillance, Epidemiology, and End Results database on 203,138 patients diagnosed with CRC between 2010 and 2016. Of these patients, 10,598 (5.2%) developed concurrent lung metastasis.
Most primary colorectal tumors occurred in the right colon (40.3%; n=81,903), followed by the left colon (33.3%; n=67,565) and the rectum (23.5%; n=47,660). Most patients received their diagnosis of CRC at grade 3 (59.1%; n=111,971), stage N0 (58.5%; n=118,929), and stage T3 (41.7%; n=84,747).
Homogeneous risk factors for lung metastasis included: older age; unmarried status; uninsured status; poor histological differentiation; increased presence of lymph, liver, bone, or brain metastasis; and carcinoembryonic antigen (CEA) positivity.
Heterogeneous risk factors included primary tumor site location and surgical resection. Patients with primary tumors in the left colon or rectum, African heritage, and T4 stage disease demonstrated increased risk for lung metastasis. Patients with primary tumors in the right colon, who did not receive surgical resection, demonstrated worse survival outcomes.
Median survival of patients with concurrent lung metastasis and CRC was 10.0 months (95% CI, 9.6-10.5 months) with 1-, 3-, and 5-year survival rates of 44.3%, 13.5% and 5.2%, respectively.
Primary tumors located in the right colon, CEA positivity, multiorgan metastasis, and poor histological differentiation worsened survival prognosis. CRC surgical resection lengthened survival times in patients with concurrent lung metastasis compared with those who did not undergo surgery (19.0 months vs 7.0 months; P <.001).
Study limitations included lack of generalizability to patients outside of synchronous lung metastasis and limited availability of chemotherapy and radiotherapy treatment information for patients with CRC, which may have influenced survival outcomes.
“In this study… a total of  homogeneous risk factors and several heterogeneous factors were identified,” the study authors concluded. “These results are helpful for clinicians to conduct clinical evaluations and individualize treatment strategies.”
Wang H, Shan X, Zhang M, Qian K, Shen Z, Zhou W. Homogeneous and heterogeneous risk and prognostic factors for lung metastasis in colorectal cancer patients. BMC Gastroenterol. 2022;22(1):193. doi:10.1186/s12876-022-02270-5