Metastatic Colorectal Cancer in Young Adults: A Study From the South Australian Population-Based Registry.
BACKGROUND
Colorectal cancer (CRC) is a common malignancy. There is growing evidence that CRC incidence is increasing in the younger population. There is controversy surrounding the prognosis of young patients with CRC. In this study we reviewed Australian patients with metastatic CRC (mCRC) who were younger than 40 years of age at the time of diagnosis of metastatic disease. To our knowledge this is the first study to focus on this age group with mCRC.


METHODS
This was a retrospective study using data from the South Australian Metastatic Colorectal Cancer database. We compared patient and disease characteristics, management approaches, and outcomes for age groups < 40 and ≥ 40. A multivariate Cox proportional hazards model was fitted to compare the survival outcomes (death from all causes) between the 2 groups.


RESULTS
From 3318 patients, 46 (1.4%) were younger than 40 years of age. In a comparison of patients in the younger than 40-year-old group with the older group, a greater proportion had synchronous metastatic disease (80.4% vs. 64.4%, respectively; P = .04) and disease originating from the left colon (71.7% vs. 61.7%, respectively; P = .035); also a larger proportion in the younger than 40-year-old group received chemotherapy compared with the older group (82.6% vs. 58.7%, respectively; P < .01). In the adjusted multivariate model, survival was not significantly different between the 2 groups (hazard ratio, 0.81; 95% confidence interval, 0.56-1.16; log rank P = .25).


CONCLUSIONS
Young-onset mCRC patients, when defined as aged younger than 40 years, have equivalent survival compared with their older counterparts. This is despite differences in disease characteristics and management approach between the 2 groups.
Department of Medical Oncology, Flinders Medical Centre, Adelaide, South Australia, Australia; Flinders Centre for Innovation in Cancer, Flinders University, Adelaide, South Australia, Australia. Electronic address: Sina.Vatandoust@health.sa.gov.au.
Sina
S
Vatandoust
Department of Medical Oncology, The Queen Elizabeth Hospital, Adelaide, South Australia, Australia; The University of Adelaide, Adelaide, South Australia, Australia.
Timothy J
TJ
Price
Flinders Centre for Epidemiology and Biostatistics, School of Medicine, Flinders University, Adelaide, South Australia, Australia.
Shahid
S
Ullah
Department of Medical Oncology, Flinders Medical Centre, Adelaide, South Australia, Australia; Flinders Centre for Innovation in Cancer, Flinders University, Adelaide, South Australia, Australia.
Amitesh C
AC
Roy
Flinders Centre for Innovation in Cancer, Flinders University, Adelaide, South Australia, Australia.
Carole
C
Beeke
The University of Adelaide, Adelaide, South Australia, Australia; Basil Hetzel Institute for Translational Health Research, The Queen Elizabeth Hospital, Adelaide, South Australia, Australia.
Joanne P
JP
Young
Department of Medical Oncology, The Queen Elizabeth Hospital, Adelaide, South Australia, Australia; The University of Adelaide, Adelaide, South Australia, Australia.
Amanda
A
Townsend
Flinders Centre for Innovation in Cancer, Flinders University, Adelaide, South Australia, Australia; Department of Surgery, Flinders Medical Centre, Adelaide, South Australia, Australia.
Robert
R
Padbury
University of South Australia, Adelaide, South Australia, Australia.
David
D
Roder
Department of Medical Oncology, Flinders Medical Centre, Adelaide, South Australia, Australia; Flinders Centre for Innovation in Cancer, Flinders University, Adelaide, South Australia, Australia.
Christos S
CS
Karapetis
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D015179:Colorectal Neoplasms / Q000235:genetics / Q000401:mortality* / Q000473:pathology* / Q000628:therapy; D005260:Female; D006801:Humans; D008297:Male; D053842:Microsatellite Instability; D015999:Multivariate Analysis; D009154:Mutation; D011379:Prognosis; D016016:Proportional Hazards Models; D048493:Proto-Oncogene Proteins B-raf / Q000235:genetics; D016283:Proto-Oncogene Proteins p21(ras) / Q000235:genetics; D012042:Registries; D012189:Retrospective Studies; D013021:South Australia; D015996:Survival Rate; D055815:Young Adult
C117307:KRAS protein, human; C482119:BRAF protein, human; D048493:Proto-Oncogene Proteins B-raf; D016283:Proto-Oncogene Proteins p21(ras)
Cancer; Colorectal cancer; Metastasis; Prognosis; Young-onset cancer