How Prior Malignancy Impacts Survival in Metastatic Colorectal Cancer

Individuals with metastatic colorectal cancer (mCRC) with prior malignancy may have a greater cancer-specific survival rate compared with those without, according to one study.¹ However, factors such as prior skin tumor or malignancy diagnosed more than 5 years earlier were linked to worse clinical outcomes.

These findings suggest the need for active, standardized treatment and broader clinical trial eligibility to ensure timely and effective management of mCRC. The population-based study is published in Scientific Reports.

New data finds that prior malignancy may influence survival outcomes in patients with metastatic colorectal cancer. | Image credit: mi_viri - stock.adobe.com

“Both patients and clinicians have long had pessimistic views regarding mCRC with a prior history of the disease,” wrote the researchers of the study. “Our data revealed that a history of prior malignancies did not negatively impact patient survival and might even contribute to prolonged survival. Surgical intervention, metastatic surgery, chemotherapy, and radiotherapy have emerged as protective factors for patients with a history of tumors.”

Colorectal cancer (CRC) is the second most-common cause of cancer-related mortality in the US and has the highest incidence among malignancies after lung cancer, breast cancer in women, and prostate cancer in men.² Therefore, CRC has become an increasingly important public health problem in the US and worldwide.

In the current study, the researchers aimed to highlight the factors that contribute survival risk in patients with mCRC with a previous history of tumors.¹

The study utilized data from the Surveillance, Epidemiology, and End Results (SEER) database to identify patients diagnosed with stage IV mCRC between 2004 and 2015, as defined by the American Joint Committee on Cancer (AJCC) 6th edition staging system.

Patients were divided into 2 groups: those with a history of prior malignancy and those without. To account for potential confounding factors, propensity score matching was applied to ensure balanced baseline characteristics between the groups. Survival outcomes were assessed, while multivariate analyses were used to evaluate the impact of prior malignancy on survival. Additionally, subgroup analyses were conducted to further explore how factors such as cancer type and time since prior malignancy influenced patient outcomes.

The study analyzed 54,365 eligible patients with mCRC of whom 4845 (8.9%) had a history of prior malignancy. The results showed that patients with a prior malignancy had a significantly greater cancer-specific survival rate compared with those without (adjusted hazard ratio [AHR], 0.49; 95% CI, 0.47-0.51).

However, subgroup analyses revealed that certain factors negatively impacted survival outcomes. Specifically, patients with a prior diagnosis of a skin tumor (AHR, 1.37; 95% CI, 1.11-1.69) and those whose prior malignancy had been diagnosed more than 5 years earlier (AHR, 1.39; 95% CI, 1.23-1.57) had worse clinical outcomes.

The researchers also acknowledged some limitations. First, the SEER database lacks quality control measures, which may have introduced bias into the results. Additionally, due to missing data, important risk factors such as nutritional status, carcinoembryonic antigen (CEA) levels, genetic testing status, and susceptibility factors could not be analyzed. Finally, since the study relied on data from a single database, further research across multiple centers is needed to confirm the generalizability of the findings.

Despite these limitations, the researchers believe the study suggests that patients with a prior malignancy diagnosis may experience prolonged cancer survival.

“Therefore, we advocate for active standardized treatment for these patients and propose expanding the range of prior malignancies included in clinical trials based on publication timelines, primary tumor locations, and genetic testing results,” wrote the researchers. “The objective is to facilitate timely and proactive treatment for patients following the disclosure of results, thereby instilling confidence in the management of mCRC.”

References

1. Qiu Y, Cao N, Meng D, et al. Survival and risk factors for metastatic colorectal cancer patients with a history of prior malignancy. Sci Rep. 2025;15(1):4045. Published Feb 3, 2025. doi:10.1038/s41598-025-88555-7

2. Menon G, Cagir B. Colon Cancer. [Updated December 21, 2024]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK470380/