Prediction of Late Breast Cancer-Specific Mortality in Recurrence-Free Breast Cancer Survivors Treated for Five Years with Tamoxifen

Prediction of cancer survivors' mortality risk in Korea: a 25-year nationwide prospective cohort study

OBJECTIVES

This study aimed to investigate the factors affecting cancer survival and develop a mortality prediction model for Korean cancer survivors. Our study identified lifestyle and mortality risk factors and attempted to determine whether health-promoting lifestyles affect mortality.

METHODS

Among the 1,637,287 participants in the Korean Cancer Prevention Study (KCPS) cohort, 200,834 cancer survivors who were alive after cancer diagnosis were analyzed. Discrimination and calibration for predicting the 10-year mortality risk were evaluated. A prediction model was derived using the Cox model coefficients, mean risk factor values, and mean mortality from the cancer survivors in the KCPS cohort.

RESULTS

During the 21.6-year follow-up, the all-cause mortality rates of cancer survivors were 57.2% and 39.4% in men and women, respectively. Men, older age, current smoking, and a history of diabetes were high-risk factors for mortality, while exercise habits and a family history of cancer were associated with reduced risk. The prediction model discrimination in the validation dataset for both KCPS all-cause mortality and KCPS cancer mortality was shown by C-statistics of 0.69 and 0.68, respectively. Based on the constructed prediction models, when we modified exercise status and smoking status, as modifiable factors, the cancer survivors' risk of mortality decreased linearly.

CONCLUSIONS

A mortality prediction model for cancer survivors was developed that may be helpful in supporting a healthy life. Lifestyle modifications in cancer survivors may affect their risk of mortality in the future.

Competing Nomogram for Late-Period Breast Cancer-Specific Death in Patients with Early-Stage Hormone Receptor-Positive Breast Cancer

BACKGROUND

More than half of early breast cancer recurrences occur after 5 years from the initial diagnosis. An individualized estimate of the risk of late-period breast cancer-specific death (LP-BCSD) after 5 years of endocrine therapy (ET) can improve decision-making for extended endocrine therapy (EET).

MATERIALS AND METHODS

A total of 147,059 eligible patients with breast cancer who survived 5+ years after diagnosis between 1990 and 2007 were identified from the Surveillance, Epidemiology, and End Results (SEER) database. Univariate and multivariate analyses based on the competing risk regression model were used to evaluate predictive factors for high risk of LP-BCSD or late-period non-breast cancer-specific death (LP-non-BCSD). Significant factors were used to build a nomogram to individualize estimates of LP-BCSD or LP-non-BCSD.

RESULTS

The 5- and 10-year LP-BCSD rates were 5.7% and 10.1%, respectively, and the 5- and 10-year LP-non-BCSD rates were 6.7% and 15.5%, respectively. Young age, black race, single marital status, poor differentiation, large tumor size, lymph node metastasis, and estrogen receptor-positive/progesterone receptor-negative (ER+/PR-) status were independent predictive factors for high risk of LP-BCSD. Age was the most important factor for predicting high risk of LP-non-BCSD. The nomograms, which were based on significant factors identified by the competing risk regression model. A risk score system based on the competing risk nomogram was established to describe the relative risk of LP-BCSD and LP-non-BCSD.

CONCLUSION

This study explored the novel endpoint of LP-BCSD for further clinical trials. The risk score system might be highly useful for patient counseling, especially in discussing EET options with elderly or comorbid patients.