Double versus Single Primary Malignant Neoplasm of Breast and Colorectal Cancer: A Case-Control Study

Area of Science:

• Oncology
• Cancer Epidemiology
• Clinical Research

Background:

• Breast cancer (BC) and colorectal cancer (CRC) are prevalent malignancies in women.
• Understanding survival outcomes for patients with multiple primary cancers is crucial for clinical management.

Purpose of the Study:

• To compare survival duration between female patients diagnosed with both BC and CRC versus those with either BC or CRC alone.
• To investigate factors influencing survival in patients with multiple primary malignancies.

Main Methods:

• Retrospective review of medical records for patients diagnosed with both BC and CRC between June 2010 and June 2021.
• Age-matched control groups with single BC or single CRC were established.
• Kaplan-Meier survival analysis was employed to compare survival rates.

Main Results:

• The 5-year survival rate for the double cancer group (74.6%) was higher than the single cancer group (63.2%).
• Patients with double primary cancers (BC and CRC) demonstrated a trend towards longer survival than those with a single cancer (116.5 vs. 101.3 months, p=0.055).
• The occurrence of a second primary cancer was more common in the double cancer cohort (p=0.015), with detection intervals varying by cancer sequence.

Conclusions:

• Breast cancer and colorectal cancer can occur as multiple primary malignancies.
• Detecting more than one cancer does not necessarily reduce survival if the second cancer is identified and treated early.
• Longer surveillance periods are recommended, and early screening should be considered for individuals diagnosed with either BC or CRC, given the potential for later occurrence of a second cancer.