A new study suggests that survivors of colorectal cancer (CRC) may have an elevated risk of second primary malignancies (SPMs). The study findings were reported in the journal Aging.

Curative resection and adjuvant chemotherapy have resulted in survival improvements for patients with CRC, while also raising concerns about the onset of SPMs, the study investigators explained in their report. “An increasing number of young CRC survivors are confronted with the threat of developing SPM,” the investigators wrote.

With this in mind, the investigators conducted a systematic review and meta-analysis by first searching PubMed, Embase, Cochrane Library, and Web of Science databases. Literature searches were aimed at studies reporting standardized incidence rates (SIRs) of SPMs after CRC, and the review included entries dated from database inception until August 2021. The investigators had a goal of pooling SIRs for both total and site-specific SPMs in survivors of CRC and with analyses conducted based on varying latency periods for the development of SPMs.

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The meta-analysis included 42 full publications, which reflected data for 1,524,236 survivors of CRC and a total of 166,210 survivors who had SPMs. Overall risk estimates for SPMs were based on 26 studies, and the remaining 16 articles were used to estimate site-specific SIRs.

SIRs were increased for total SPMs in CRC survivors across analyses by latency period. With a 1-year latency period, the SIR was 1.16 (95% CI, 1.10-1.23); with a 5-year latency, the SIR was 1.18 (95% CI, 1.09-1.28); and with a 10-year latency, the SIR was 1.24 (95% CI, 1.11-1.39). With no restriction by latency period, the SIR for SPMs was 1.15 (95% CI, 1.08-1.23).

CRC survivors had a higher risk of developing a second CRC (SIR, 1.59; 95% CI, 1.38–1.83), SPMs of the corpus uteri (SIR, 2.11; 95% CI, 1.62–2.76), and SPMs of the small intestine (SIR, 4.00; 95% CI, 2.91–5.49). Results for these cancers were similar regardless of lag times.

The researchers also found that CRC survivors were more likely to develop SPMs of the prostate, female breast, ovaries, stomach, urinary bladder, kidney, thyroid, bone, and soft tissue. However, results were not consistent when
analyses were stratified by different lag times.

“In summary, for the first time, we reported that CRC survivors are associated with an increased risk of SPMs, especially neoplasms of colorectum, corpus uteri, and small intestine,” the investigators concluded.


Du S, Li Y, Sun H, et al. The risk of developing second primary malignancies among colorectal cancer patients. Aging (Albany NY). Published online August 26, 2022. doi:10.18632/aging.204250

This article originally appeared on Oncology Nurse Advisor