As with many cancers, the prognosis for older patients with HCC is worse than for younger patients as elderly patients are often found to have more comorbidities such as cardiovascular disease, nutritional and metabolic disorders, conditions that can lead to the development of primary cancer(Kendal 2008). At the meantime, due to the lack of effective surveillance, older patients are often diagnosed at an advanced stage(Bakogeorgos, Mountzios et al. 2013, Strøm, Bremnes et al. 2015, Sun, Liu et al. 2022). Coupled with the current international environment of an aging population, this article hence focuses on the prognostic factors affecting hepatocellular carcinoma in the elderly.The main method for assessing HCC disease progression, treatment options, and prognosis is the TNM staging system released by the American Joint Committee on Cancer (AJCC), but this staging system contains fewer clinical parameters and is applied to all cancer populations, which is not targeted enough to predict the prognosis of HCC, especially in elderly patients with HCC. Nomogram based on AJCC staging combined with other clinical parameters, demographic characteristics have been widely used as a convenient and effective tool for prediction of survival time, and their accuracy and validity have been validated in other cancers (Mao, Fu et al. 2021, Tong, Li et al. 2021, Wang, Zhanghuang et al. 2022).In this article, we successfully attempted to predict OS in elderly patients with hepatocellular carcinoma using the construction of a combined nomogram with the above parameters, in combination with clinical parameters(Pathologic grading and TNM staging), demographic characteristics(Age), and treatment information(surgery, radiation and chemotherapy).OS decreases significantly with the increase of age. Therefore, more attention should be paid to elderly patients with hepatocellular carcinoma in clinical.However, unlike the findings of Xu(Xu, Qin et al. 2023), in this paper, PVTT was not statistically significant to OS. Our results suggest that this nomogram has satisfactory accuracy and discriminative ability in predicting 1-year OS, but poorer efficacy in predicting 3- and 5-year OS, which may be related to the fact that our study population was an elderly group, whose own characteristics determine that their long-term survival is affected by numerous factors, all of which may contribute to the decline in the predictive efficacy of the nomogram.In addition, we used calibration curves in the training and validation cohorts to verify whether there is a good agreement between the predicted and actual observed survival rates of nomogram, and the results presented good prediction accuracy.Next, we introduce a scoring system based on nomograms, which calculates the contribution of each variable in the nomogram to OS according to the equation to obtain a point, and the score of each patient is equal to the sum of the points of these variables.Patients were then divided into high-risk and low-risk groups based on the scores, and this distinction was confirmed in the training cohort and validation cohort to be significant for OS.With the assistance of this risk stratification system methodology, risk stratification of patients can be achieved in the clinic to increase the attention to the high-risk group and to improve the poor prognosis of these patients by taking active interventions as early as possible.
We also considered the drawbacks of using the SEER database and remedied them:(1) (1)Because the database collects information on cancer patients in the United States, the variable of race is somewhat biased, so race information was not used to create the regression equation.(2)Since the treatment of HCC patients is determined by the physician based on the patient's condition, i.e., the decision for a patient to undergo surgery/radiation/chemotherapy is the result of the physician's careful patient selection.This non-randomization bias may affect the comparison of overall survival between patients, this limitation can only be tackled by the RCT approach, but based on ethical considerations, we cannot randomize patients’ treatment modalities in order to carry out a research without taking into account their specific conditions.To minimize data bias and interference by confounding factors, we grouped patients with surgery, chemotherapy, and radiotherapy separately, and then used PSM to match other variables, fully considering the independent correlations of all other variables with the grouped variables, to further compare the differences in patient survival between treatment modalities more accurately,which can help in the selection of optimal clinical treatment decisions for patients.
In this part of the results we found that (1) Dividing the patients into radiotherapy and non-radiotherapy groups, PSM controlled for bias and the results showed that although the median overall survival was significantly higher in the radiotherapy group (12–15 months) than in the non-radiotherapy group (6–9 months, Fig. 6C).However, when subgroups were analyzed, it was found that in the T4 subgroup, radiotherapy patients had a worse prognosis than those who did not receive radiotherapy, and the same results were found in the Grade IV subgroup.This is different from the findings of Xu et al(Xu, Qin et al. 2023). In response to this result, we have two considerations .Firstly, it may suggest that in elderly patients with poorly staged hepatocellular carcinoma, radiotherapy causes destruction of surrounding normal tissues and may not be conducive to long-term prognosis, especially in the elderly group(Seong 2009).Moreover, in recent years, many studies have shown that many cancer patients end up dying not from the primary cancer but from complications after radiotherapy, the most common complications being severe infections secondary to immunocompromised, radioactive ulcers(Seong 2009, Peixoto, Hammond et al. 2014).The second is that this study did not continue to group the patients according to the radiotherapy method, and the effect of different types of radiotherapy on the prognosis may be different. In recent years, many studies have confirmed that stereotactic radiotherapy, compared with conventional radiotherapy, permits a higher dose of treatment to the tumor site, and plays a more favorable role in the long-term prognosis of patients with hepatocellular carcinoma than conventional radiotherapy(Ohri, Dawson et al. 2016). The specific radiotherapy modality of the patients in the radiotherapy group in our paper is not clear, which may also cause some bias to the results.(2) As with other findings,among the surgery and no-surgery groups, we found that the overall survival of patients in the surgery group was significantly longer than that of no-surgery patients(Hu, You et al. 2019, He, Chen et al. 2021, Su, Shen et al. 2023). Subgroup analyses also showed that surgery was not only beneficial for patients aged 65–75 years, with well-differentiated tumors, and who had been treated with radiotherapy, but also had a positive impact on patients with poor prognostic factors (including age ≥ 75 years and poorly-differentiated tumors), and could improve the survival of this group of patients; therefore, it is worthwhile to further explore the possibility of expanding the indications for surgery in a follow-up study.Although this article develops the first nomogram on OS prediction in elderly HCC patients, its limitations should be noted. Firstly, this paper has not been externally validated. Further external validation using a multicenter cohort with a large sample size is necessary to confirm the performance of nomogram. Secondly, we did not specific analyze the effect of different surgical modalities and different radiotherapy regimens on the prognosis of HCC, which still has a certain degree of bias. Finally, the SEER database lacks some other prognostic factors, such as surgical margin status, laboratory data (bilirubin, albumin, AFP, etc.), which are not included in the nomogram and may also be a certain degree of decline in the nomogram efficacy, all of which should be evaluated in future studies.Conclusion
The nomogram constructed in this article based on demographic characteristics, clinical parameters and treatment information effectively fills the gap in prognosis prediction of elderly HCC patients, and the risk stratification system can effectively identify high-risk patients for early intervention to improve their poor prognosis. Therefore, this nomogram can be used as an effective tool to guide the individualized treatment and follow-up management of elderly HCC patients.