TY - JOUR
T1 - Comparison of survival of patients with metastases from known versus unknown primaries
T2 - Survival in metastatic cancer
AU - Riihimäki, Matias
AU - Thomsen, Hauke
AU - Hemminki, Akseli
AU - Sundquist, Kristina
AU - Hemminki, Kari
N1 - Funding Information:
This work was supported by Deutsche Krebshilfe and the Swedish Council for Working Life and Social Research. A.H. is K. Albin Johansson Research Professor of the Finnish Cancer Institute.
PY - 2013/1/28
Y1 - 2013/1/28
N2 - Background: Cancer of unknown primary site (CUP) is considered an aggressive metastatic disease but whether the prognosis differs from metastatic cancers of known primary site is not known. Such data may give insight into the biology of CUP and the metastatic process in general.Methods: 6,745 cancer patients, with primary metastatic cancer at diagnosis, were identified from the Swedish Cancer Registry, and were compared with 2,881 patients with CUP. Patients were diagnosed and died between 2002 and 2008. The influence of the primary site, known or unknown, on survival in patients with metastases at specific locations was investigated. Hazard ratios (HRs) of death were estimated for several sites of metastasis, where patients with known primary sites were compared with CUP patients.Results: Overall, patients with metastatic cancers with known primary sites had decreased hazards of death compared to CUP patients (HR = 0.69 [95% CI = 0.66-0.72]). The exceptions were cancer of the pancreas (1.71 [1.54-1.90]), liver (1.58 [1.36-1.85]), and stomach (1.16 [1.02-1.31]). For individual metastatic sites, patients with liver or bone metastases of known origin had better survival than those with CUP of the liver and bone. Patients with liver metastases of pancreatic origin had an increased risk of death compared with patients with CUP of the liver (1.25 [1.06-1.46]). The median survival time of CUP patients was three months.Conclusions: Patients with CUP have poorer survival than patients with known primaries, except those with brain and respiratory system metastases. Of CUP sites, liver metastases had the worst prognosis. Survival in CUP was comparable to that in metastatic lung cancer. The aggressive behavior of CUP may be due to initial immunosuppression and immunoediting which may allow accumulation of mutations. Upon escape from the suppressed state an unstoppable tumor spread ensues. These novel data on the epidemiology of the metastatic process at the population level demonstrated large survival differences in organ defined metastases depending on the original cancer.
AB - Background: Cancer of unknown primary site (CUP) is considered an aggressive metastatic disease but whether the prognosis differs from metastatic cancers of known primary site is not known. Such data may give insight into the biology of CUP and the metastatic process in general.Methods: 6,745 cancer patients, with primary metastatic cancer at diagnosis, were identified from the Swedish Cancer Registry, and were compared with 2,881 patients with CUP. Patients were diagnosed and died between 2002 and 2008. The influence of the primary site, known or unknown, on survival in patients with metastases at specific locations was investigated. Hazard ratios (HRs) of death were estimated for several sites of metastasis, where patients with known primary sites were compared with CUP patients.Results: Overall, patients with metastatic cancers with known primary sites had decreased hazards of death compared to CUP patients (HR = 0.69 [95% CI = 0.66-0.72]). The exceptions were cancer of the pancreas (1.71 [1.54-1.90]), liver (1.58 [1.36-1.85]), and stomach (1.16 [1.02-1.31]). For individual metastatic sites, patients with liver or bone metastases of known origin had better survival than those with CUP of the liver and bone. Patients with liver metastases of pancreatic origin had an increased risk of death compared with patients with CUP of the liver (1.25 [1.06-1.46]). The median survival time of CUP patients was three months.Conclusions: Patients with CUP have poorer survival than patients with known primaries, except those with brain and respiratory system metastases. Of CUP sites, liver metastases had the worst prognosis. Survival in CUP was comparable to that in metastatic lung cancer. The aggressive behavior of CUP may be due to initial immunosuppression and immunoediting which may allow accumulation of mutations. Upon escape from the suppressed state an unstoppable tumor spread ensues. These novel data on the epidemiology of the metastatic process at the population level demonstrated large survival differences in organ defined metastases depending on the original cancer.
KW - CUP
KW - Cancer of unknown primary
KW - Cancer survival
KW - Metastasis
KW - Regression analysis
UR - http://www.scopus.com/inward/record.url?scp=84872781432&partnerID=8YFLogxK
U2 - 10.1186/1471-2407-13-36
DO - 10.1186/1471-2407-13-36
M3 - Article
C2 - 23356713
AN - SCOPUS:84872781432
SN - 1471-2407
VL - 13
JO - BMC Cancer
JF - BMC Cancer
M1 - 36
ER -