EP.FRI.121 Unusual sites of colorectal cancer metastases – A complete systematic review

Background While colorectal cancer (CRC) usually metastasizes to liver, lungs and central nervous system, spread to more unusual sites is rarely reported in literature. We aimed to investigate unusual colorectal metastases (UCRM), their clinical course and disease progression. Methods MEDLINE, EMBASE and Cochrane Library were searched by independent reviewers to identify clinical studies to date that reported UCRM and relevant demographic/clinical data were extracted. Results We identified 349 patients, involving 28 sites (bone, musculo-skeletal, skin, brain/spinal cord, head, eye, oral mucosa, thyroid, mediastinum, heart, bronchus, breast, biliary/GI tract, stomach, pancreas, spleen, adrenal, urinary tract, inguinal canal, ovaries, vagina, vulva, testes, spermatic cord, prostate, penis) with male preponderance and median age of 59 years (IQR=54.5-65). These were diagnosed at a median interval of 18 months (IQR=6-36)) after a median follow-up of 12 months (IQR=6-22.5). More were metachronous (n = 210) with recurrence rate of 15.75%. Primary CRC staging revealed T3 in 61% (28%-T4), equal distribution of N0/N1 (38%/37%) and M0 in 85%. 74% of primaries were surgically resected (96%=adenocarcinomas) and 54% underwent adjuvant therapy. UCRM were resected in 45% of cases and showed same histology as primary. 30% had chemotherapy. Only 8% were palliated. Overall morality was 35.24%. Conclusion This is the first comprehensive review looking at clinical course and outcomes of patients with UCRM. Most of these developed in patients with primary T3/N0 staging. Outlook of these patients is comparable to those with usual metastatic disease. Judicious and rigorous surveillance is the key to early detection and timely management.