Ito Yuri, Ohno Yuko, Rachet Bernard, Coleman Michel P, Tsukuma Hideaki, Oshima Akira
Graduate School of Medicine, Osaka University, Osaka, Japan.
Jpn J Clin Oncol. 2007 Jun;37(6):452-8. doi: 10.1093/jjco/hym047. Epub 2007 Jul 16.
Five-year survival is an important index for evaluating the overall effectiveness of cancer diagnosis and treatment. The aim of this study was to monitor trends in 5-year cancer survival in Osaka, Japan, during 1975-94, with adjustment for trends in age and stage at diagnosis.
Five-year crude survival was estimated for cancers of the stomach (39,697 patients), lung (17,400 patients) and breast (11,988 women) in four consecutive 5-year periods, with adjustment for age and/or stage, using the age and stage distribution of cases diagnosed during 1975-79 as standard weights. We estimated the impact of adjusting for either age or stage alone by their proportionate impact on the trend in fully (age- and stage-) adjusted survival.
The absolute increase in unadjusted 5-year survival over 20 years was about 20% for stomach cancer, 14% for breast cancer and 5% for lung cancer. Lack of age adjustment would have caused proportionate under-estimation of these trends by 13-14% (stomach), 7% (breast), 14% (lung, men) and 4% (lung, women). Lack of adjustment for the trend toward earlier stage would have caused proportionate over-estimation (152%, men: 133%, women) of stomach cancer survival trends, which seemed more influenced by earlier diagnosis than more effective treatment. For breast cancer, the 31% over-estimation of trend from lack of stage adjustment suggests the impact of earlier diagnosis, while the improvement of survival after additional adjustment for age may be due to more effective treatment. Failure to adjust for stage led to a proportionate 21% under-estimation of lung cancer survival trends for men, and 4% over-estimation for women.
This study confirms the importance of adjusting for trends in age and stage distribution when evaluating time trends in cancer survival.
五年生存率是评估癌症诊断和治疗总体效果的重要指标。本研究旨在监测1975 - 1994年期间日本大阪市五年癌症生存率的趋势，并对诊断时的年龄和分期趋势进行调整。
采用1975 - 1979年期间确诊病例的年龄和分期分布作为标准权重，对连续四个五年期内胃癌（39697例患者）、肺癌（17400例患者）和乳腺癌（11988例女性）的五年粗生存率进行估计，并对年龄和/或分期进行调整。我们通过单独调整年龄或分期对完全（年龄和分期）调整生存率趋势的比例影响，来估计其影响。
20年间，未经调整的胃癌五年生存率绝对增幅约为20%，乳腺癌为14%，肺癌为5%。未进行年龄调整会导致这些趋势被按比例低估13 - 14%（胃癌）、7%（乳腺癌）、14%（肺癌，男性）和4%（肺癌，女性）。未对分期提前的趋势进行调整会导致胃癌生存率趋势被按比例高估（男性152%，女性133%），这似乎更多地受到早期诊断而非更有效治疗的影响。对于乳腺癌，因未进行分期调整而导致趋势被高估31%，这表明了早期诊断的影响，而在进一步调整年龄后生存率的提高可能归因于更有效的治疗。未对分期进行调整导致男性肺癌生存率趋势被按比例低估21%，女性被高估4%。
本研究证实了在评估癌症生存率的时间趋势时，对年龄和分期分布趋势进行调整的重要性。
