Comments on 'standard and reference-based conditional mean imputation': Regulators and trial statisticians be aware!

Accurate frequentist performance of a method is desirable in confirmatory clinical trials, but is not sufficient on its own to justify the use of a missing data method. Reference-based conditional mean imputation, with variance estimation justified solely by its frequentist performance, has the surprising and undesirable property that the estimated variance becomes smaller the greater the number of missing observations; as explained under jump-to-reference it effectively forces the true treatment effect to be exactly zero for patients with missing data.

Estimation of a treatment policy estimand for time to event data using data collected post discontinuation of randomised treatment

Discontinuation from randomised treatment is a common intercurrent event in clinical trials. When the target estimand uses a treatment policy strategy to deal with this intercurrent event, data after cessation of treatment is relevant to estimate the estimand and all efforts should be made to collect such data. Missing data may nevertheless occur due to participants withdrawing from the study and assumptions regarding the values for data that are missing are required for estimation. A missing-at-random assumption is commonly made in this setting, but it may not always be viewed as appropriate. Another potential approach is to assume missing values are similar to data collected after treatment discontinuation. This idea has been previously proposed in the context of recurrent event data. Here we extend this approach to time-to-event outcomes using the hazard function. We propose imputation models that allow for different hazard rates before and after treatment discontinuation and use the posttreatment discontinuation hazard to impute events for participants with missing follow-up periods due to study withdrawal. The imputation models are fitted as Andersen-Gill models. We illustrate the proposed methods with an example of a clinical trial in patients with chronic obstructive pulmonary disease.

Examining untreated and treated alcohol problem resolution in an Australian online survey sample

INTRODUCTION

While treatment is an effective way to resolve alcohol problems, many people resolve their alcohol problems in the absence of treatment. Just how many do so is not known and may vary based on the definition of treatment. Various estimates of untreated alcohol problem resolution were calculated in this study, and the differences between people who resolve their alcohol problems with or without treatment were explored in relation to sociodemographic variables, levels of alcohol consumption in the past 12 months and lifetime alcohol problem severity.

METHODS

A cross-sectional online survey was administered to 719 people who had resolved an alcohol problem in Australia. Convenience sampling was used through a recruitment strategy targeted towards the general population via Facebook.

RESULTS

Almost half (49.8%) of all people who resolved their alcohol problem did so in the absence of alcohol treatment, whether specialist alcohol treatment, mutual-aid services or digital support services. When accessing mental health treatment is included under the scope of 'treatment', this estimate dropped to 12.8%. The estimated odds of having accessed treatment increased with age and lifetime alcohol problem severity. Other sociodemographic variables, or levels of alcohol consumption in the past 12 months, were not significantly associated with treatment status.

DISCUSSION AND CONCLUSIONS

It might be beneficial to expand the scope of 'treatment' to include mental health services and focus on the development of cost-effective and less intrusive standalone activities, which can expedite and support alcohol problem resolution for those who choose not to access specialist treatment.

Impact of COVID-19 pandemic on a daily-based outpatient treatment routine: experience of a radiotherapy department of a tertiary public/university hospital in Brazil

OBJECTIVES

To report the impact of the COVID-19 pandemic on patient attendance at a radiotherapy department two months after the implementation of specific policies regarding the pandemic.

METHODS

The proposed treatment schemes, favoring hypofractionated schedules, and COVID-19 management strategies regarding irradiation are presented. Attendance after two months of implementation of these policies was measured and compared with that during the same period in 2019.

RESULTS

A 10% reduction in the number of treated patients and a 26% reduction in the number of sessions was observed. The main impact was a decrease in the treatment of benign diseases and gastrointestinal tumors, with a general increase in breast cancer treatments. Eighteen (1.7%) patients were confirmed as having COVID-19 during radiotherapy in April and May 2020, three of whom were hospitalized, and one patient died because of COVID-19. Among the 18 patients, 12 had their treatments interrupted for at least 15 days from symptom appearance.

CONCLUSION

There was a decrease in the number of treated patients in our radiotherapy department, with a greater decrease in the total number of sessions. This indicated, overall, a smaller number of fractions/patients treated, despite our efforts to maintain the treatment routine. We had several patients who were infected with COVID-19 and one related death during treatment in the first few months of the pandemic in São Paulo Brazil.

Primary pancreatic lymphoma: two case reports and a literature review

Primary pancreatic lymphoma (PPL) is an extremely rare disease, with only a few cases reported in the literature. Clinical manifestations of PPL are often nonspecific and may mimic other pancreatic diseases. Because of the limited experience of PPL, clinicopathological features, differential diagnosis, optimal therapy, and outcomes are not well defined. We described two cases diagnosed as PPL and confirmed by histological examination and immunohistochemical analysis. Case 1 was a young man with obstructive jaundice and upper abdominal malaise mimicking a pancreatic adenocarcinoma. A computed tomography (CT) scan revealed a diffuse heterogeneous mass in the head of the pancreas along with dilated bile ducts, no dilated pancreatic duct, no liver or splenic involvement, or evident retroperitoneal adenopathies. The patient underwent a pancreatico-duodenectomy, and the postoperative histopathology confirmed diffuse large B-cell non-Hodgkin lymphoma. Postoperatively, he received six courses of the CHOP regimen (cyclophosphamide, doxorubicin, vincristine, and prednisolone). Case 2 was an older man with left flank pain. A CT confirmed a mass with irregular margins at the tail of the pancreas and the hilum of the spleen. The mass was heterogeneous, with no clear boundary between lesions, spleen, stomach, and pancreas, with nearby blood vessels wrapped around it, and multiple enlarged lymph nodes in the abdominal cavity. A CT-guided biopsy was performed. The immunohistological findings of the specimen revealed a diffuse large B-cell lymphoma. The size of the tumor was significantly reduced after four cycles of the CHOP chemotherapy regimen. These two cases were different in clinical manifestation, location, and treatment. We reviewed the literature and discussed the clinicopathological features, differential diagnosis, optimal therapy, and outcomes of this neoplasm.

Low-grade nasopharyngeal papillary adenocarcinoma: a case report and review of the literature

Low-grade nasopharyngeal papillary adenocarcinoma is an extremely rare tumor, with only a limited number of cases reported in the literature. Some published studies have paid more attention to the clinicopathological features of nasopharyngeal adenocarcinoma, while little effort has been made to study the optimal therapeutic strategies. We report about a woman diagnosed with low-grade nasopharyngeal papillary adenocarcinoma. She received the treatment approach that combined transnasal endoscopic surgery to remove the lesion with postoperative radiotherapy for nasal cavity. There was no evidence of recurrence after 4 months of surgery, and further follow-up is being continued. Through this example, we wanted to explore the optimal therapeutic strategies for primary nasopharyngeal adenocarcinomas.