Here, we examined the antiemetic status for CINV among 1,082 newly diagnosed and treated lung cancer patients receiving carboplatin-based chemotherapy between 2016 and 2017 in the Hokushin region based on the Hokushin Ganpro dataset 2 consisting of HBCRs and DPCs. We found that prophylactic antiemetics were prescribed in all patients in accordance with the guidelines. The rate of double antiemetic therapy was slightly higher than triple antiemetic therapy, but the distribution and use of palonosetron were quite different between the four prefectures.
There have been several real-world cohort studies regarding the adherence to international clinical guidelines for CINV. Multiple prospective observational studies in the USA showed that the prevalence of guideline-consistent CINV prophylaxis was 73.1% in MEC regimens including carboplatin . Aapro et al.  summarized the data in Global Oncology Monitor database (Ipsos Healthcare, London, UK), which collected patients’ medical charts from 610 representative physicians in five counties (France, Germany, Italy, Spain, and the UK). They showed that only 15% of all patients treated with HEC and carboplatin-based chemotherapy received guideline-recommended triple antiemetic prophylaxis. On the other hand, multicenter, prospective, observational studies in Japan showed that approximately 95% of patients treated with MEC (including carboplatin) received antiemetic therapy in compliance with the guidelines . Based on these reports, double and triple antiemetics were prescribed in 67% and 28% of cases receiving MEC, respectively . Subsequently, Okuyama et al.  summarized combined health service utilization and HBCR data and reported that 59.1% and 24.0% of patients treated with intravenous MEC received double and triple antiemetic prophylaxis, respectively, in Japan. Our results were focused on carboplatin-based chemotherapy and lung cancer. However, we found that 100% of patients were treated with prophylactic antiemetics in accordance with the guidelines. In addition, triple antiemetic therapy was prescribed in 46% of enrolled subjects in Hokushin region, which was a higher rate than in previous Japanese studies [8–10]. Recently, Iihara et al.  summarized the CINV pattern and status in patients treated with carboplatin-based chemotherapy and performed a comparison between double and triple antiemetic prophylaxis groups (69.4% and 30.6%, respectively). They suggested that triple antiemetic therapy was appropriate for antiemetic prophylaxis in patients with carboplatin-induced CINV because double antiemetic therapy was a risk factor for incomplete response of CINV. However, they also reported that there was no significant difference in control of CINV between double and triple antiemetic regimens in lung cancer patients . Several studies showed that adding neurokinin-1 receptor antagonist improved carboplatin-induced CINV [6, 16], but the results were not consistent with other studies [17–19], including in lung cancer [9, 18, 19]. Therefore, although we found a relatively high rate of triple antiemetic regimen use in Hokushin region compared with other studies [8–10], further studies are needed regarding the effects of adding neurokinin-1 receptor antagonist to each carboplatin-based regime and different types of cancer.
Palonosetron is preferred to first-generation 5-hydroxytryptamine-3 receptor antagonists, such as granisetron or ondansetron, for MEC or HEC, and has proven useful for preventing both acute and delayed CINV . Palonosetron was used dominantly in both double and triple antiemetic regimens in the present study. In addition, although double antiemetic therapy was prescribed frequently in Toyama and Fukui prefectures, palonosetron was mainly selected as the 5-hydroxytryptamine-3 receptor antagonist in these prefectures, which was reasonable for better prophylaxis for CINV. In contrast, palonosetron was used less often in Nagano prefecture. Although the reasons were not clear, but these real-world data were informative for reviewing cancer management in this region.
It is noteworthy that 39 patients (3.6%) changed from double to triple antiemetic therapy after the second cycle of carboplatin treatment in the present study. In contrast, 41 patients changed from triple to double antiemetic therapy after the second cycle of carboplatin treatment, but six of these patients returned to the triple regimen at subsequent cycles. We were unable to evaluate the severity of CINV in each patient, but these data suggested that possibly maximal CINV prevention was required even in cases of carboplatin-based chemotherapy. It was reported that the carboplatin + pemetrexed regimen, which is commonly used in lung cancer, had a higher risk of causing delayed nausea than the carboplatin + paclitaxel regimen that is widely used in various cancers . Therefore, the optimal antiemetic therapy for lung cancer patients should be determined carefully, even for carboplatin-based chemotherapy. The optimal preventive antiemetic regimen for lung cancer patients receiving carboplatin remains unclear. However, optimal antiemetic prophylaxis should be considered according to the cancer type and regimens in patients treated with carboplatin-based chemotherapy.
The present study had some limitations. First, this was a retrospective review with a relatively small population and we were unable to evaluate the baseline characteristics, including patient performance status, comorbidities, etc. In addition, this study did not assess the status and/or frequency of CINV in each patient. The Hokushin Ganpro Database does not necessarily contain all HBCR data for the Hokushin region. Therefore, care should be taken in comparing double and triple antiemetic prophylaxis between prefectures. Nevertheless, our survey data corresponding to each registered case in the Hokushin Ganpro dataset provided the details of real-world practice and could be helpful in understanding the real-world clinical situation regarding treatment and management of lung cancer in the Hokushin region.
In conclusion, we described clinical practice for prevention of CINV related to carboplatin chemotherapy in patients with lung cancer in the Hokushin region, Japan. This area showed an extremely high adherence to antiemetic guidelines. However, antiemetic patterns differed between the four prefectures in Hokushin region. The cancer registry system, including health care utilization data, is a valuable resource for obtaining useful information about treatment and management of patients with lung cancer.