Corticosteroids are used to relieve dyspnea in patients with cancer. They could be effective in treating dyspnea in patients with cancer caused by specific pathological conditions such as lymphangitis carcinomatosa, central airway obstruction, and superior vena cava syndrome [6], but the effect has not yet been elucidated [12] [13].
We believe that prognostic predictions might reflect the effects of corticosteroids [7], because healthcare professionals believe that corticosteroids are ineffective in patients with cancer considered to have a short survival [14], and its effects generate a good survival [8]. However, as far as we know, no finding clarifies these facts. Thus, this is the first study to clarify the relationship between the effects of corticosteroids on dyspnea in patients with cancer, prognostic indicators, and actual survival.
From our findings, actual survival was the best predictor of corticosteroid effects compared to other factors. Generally, corticosteroids are drugs administered to relieve symptoms, not with the intention of prolonging patient survival. However, dyspnea in patients with cancer is a factor that affects their survival, and various indicators reveal it as a prognostic factor [9] [10] [15]. A previous report also showed that corticosteroid administration may be associated with patient prognosis [16]. In addition, many central airway obstruction and lymphangitis carcinomatosa are considered to have a strong effect on patients’ survival, and relief of such life-threatening conditions may directly lead to prolonged life [17] [18].
If the effect of corticosteroids on dyspnea is related to patient survival, it may be predicted by the prognosis prediction index before its administration. Although various indices are used for prognostic prediction, the PaP score is a universal prognostic index. Although this score is difficult to use in the clinical or palliative medicine because of the need for blood sampling, prognostic indicators including blood tests are more accurate in predicting accurate survival [19]. In this study, the actual survival could be accurately stratified by the PaP score, and it functioned well as a prognostic index. However, the PaP score and corticosteroid effects were not correlated [7], while the actual survival was accurately reflected in corticosteroid effects. This suggests that the PaP score was still insufficient as a prognostic predictive tool, and it may be possible to predict the effect of corticosteroids on dyspnea if a more accurate prognosis can be predicted. We also examined other factors that may predict the effects of corticosteroids. However, the actual survival of the patient was the most predictable of the effect of corticosteroids compared to the factors shown so far. It is possible that this was because previous studies did not investigate actual survival.
This data was less effective for corticosteroids on dyspnea than reported previously [13]. It was considered that the effects of corticosteroids were insufficient because the dose of corticosteroids used was less than usual. However, there is no clear standard for the dose of corticosteroids for dyspnea, and in clinical practice, the dose is often lower than the usual dose, especially when administered to patients with a short-term survival such as a palliative care unit. The dose of corticosteroid used was approximately the same as the dose used in other Japanese palliative care units [14], and the efficacy was similar to the experienced efficacy rate [4]. Furthermore, in this study, there was no correlation between the initial dose of corticosteroids and their effect [20]. In addition, the effect of corticosteroids might be low in patients with short survival, so it was considered that the response rate was low when there were many patients with short survival, as in this case.
There were several limitations to our study. First, this was a retrospective study. Since the effect of corticosteroids on dyspnea was not scored on a subjective scale but from the perspective of the medical staff, there might be an overdiagnosis bias thereby suggesting that corticosteroids are effective. However, the PaP score, which is a subjective evaluation, was evaluated at the time of corticosteroid administration, and the bias was minimized as much as possible. In addition, suggestions reveal the difficulty to evaluate terminal dyspnea symptoms on a subjective scale [21]; therefore, in this study, an objective evaluation was performed by medical professionals.
Although the presence or absence of lung lesions was analyzed, we did not investigate the details associated with these lesions, such as central airway obstruction and lymphangitis carcinomatosa. This was because many investigated cases had lung abnormalities, in addition to cancer, chronic obstructive pulmonary disease, and interstitial pneumonitis, as well as drug-induced pneumonitis and radiation pneumonitis associated with cancer treatment. In this study, as many thoracic lesions were not organized in grades, it was difficult to evaluate each of them, though the presence or absence of lung lesions was evaluated. Similarly, abdominal lesions were evaluated including liver metastasis and peritoneal dissemination. Moreover, for end-of-life patients with a mixture of various lesions, we could presume such an evaluation as more suitable for actual clinical practice.
In conclusion, patients with long-term survival were more likely to expect the effect of corticosteroids, though difficult to accurately predict it with the prognosis prediction still in use. With the development of a more accurate prognosis prediction method, it may be possible to predict the effect of corticosteroids on dyspnea by using it before administration.