AB0307 MERKEL CELL CARCINOMA RECURRENCE RISK IS LOWER IN PATIENTS WITH AUTOIMMUNE DISEASE THAN IN THOSE WITH OTHER TYPES OF IMMUNE SUPPRESSION

Background

Merkel cell carcinoma (MCC) is twice as likely to recur in immunosuppressed (IS) patients as in immunocompetent (IC) patients. Iatrogenic IS due to autoimmune disease (AD) may influence prognosis differently than intrinsic IS such as due to hematologic malignancy. Moreover, modification of IS medication may improve prognosis.

Objectives

Our objective was to evaluate the risk of MCC recurrence among patients with AD diseases relative to other immunosuppressive conditions among 762 MCC patients from an Institutional review board-approved registry.

Methods

We categorized patients into 3 groups: IS due to AD (ISAD); IS from other causes (lSnon-AD) such as hematologic malignancy, solid organ transplant, human immunodeficiency virus; or immune competent (n=31, 70, and 661 respectively). ISAD patients were subcategorized into rheumatoid arthritis (RA) (ADRA, n=13) vs. AD except for RA (ADnon-RA, n=18). Descriptive statistics were used to compare the features of different characteristics in each group. Kaplan-Meier survival curves were constructed to assess the cumulative incidence of recurrence in different patient groups. In order to estimate the associations between baseline patient characteristics and the risk of MCC recurrence, Fine and Gray regression models were used with death as a competing risk for recurrence. The multivariable models adjusted for age, sex, and extent of MCC at initial presentation.

Results

Patients with ISAD had lower stage disease (local disease: 58% vs. 36%, p = 0.003) and smaller primary tumors than ISnon-AD (<= 2 cm: 83% vs. 57%, p=0.023). After adjusting for age, sex, and stage, ISAD patients (ADRA and ADnon-RA) overall had a 54% higher recurrence rate (hazard ratio (HR): 1.54, p=0.21) than IC patients. In comparison, ISnon-AD group had a 165% higher recurrence rate (HR: 2.65, p<0.001) than IC patients (Figure 1). When considered separately, ADRA pts appeared to have a similar recurrence rate as IC pts (HR: 1.19, p=0.76) while ADnon-RA pts had a higher recurrence rate (HR: 1.83, p=0.16) relative to IC pts. At the time of MCC diagnosis, 80% (n=24) of AD pts were on IS medication including conventional disease modifying drugs, biologics, or oral steroids. After MCC diagnosis, 22% (5 patients) stopped all immunosuppressive medications. Among patients on biologics, 89% (8/9 pts) elected to stop the drug. Eleven pts with AD experienced recurrences. Our study was underpowered to demonstrate associations regarding use of a particular immunosuppressive medication and MCC recurrence.

Figure 1.

Cumulative incidence of Merkel cell carcinoma recurrence in different patient groups.

AD = autoimmune disease; IS = immunosuppressed; RA = rheumatoid arthritis.There were 4/13, 8/18, 49/70, and 217/661 recurrences in the RA, ADnon-RA, other immunosuppressed, and not chronically immunosuppressed groups, respectively. Follow-up time ranged from 26 days to 16 years, with median follow-up times of 4.7 years, 1.6 years, 1.6 years, and 3.9 years for the RA, ADnon-RA, other immunosuppressed and not chronically immunosuppressed groups, respectively.

Conclusion

In this cohort, pts with AD appeared to have a better prognosis than intrinsic IS, with RA conferring very little risk above that for immune competent pts.

Acknowledgements

I have no acknowledgements to declare.

Disclosure of Interests

None declared

Use of CTA Test Dose to Trigger a Low Cardiac Output Protocol Improves Acute Stroke CTP Data Analyzed with RAPID Software

BACKGROUND AND PURPOSE

Contrast curve truncation in CTP protocols may introduce errors. We sought to identify risk factors and design a protocol to avoid truncation while limiting radiation.

MATERIALS AND METHODS

In an initial fixed-timing cohort, patients underwent a 65-second CTP with 2-second delay postcontrast injection. Multivariable analysis identified factors associated with truncation. A later case-specific cohort underwent either the original protocol or a low cardiac output protocol with a 7-second delay and 75-second scanning window, with selection determined by CTA test-dose enhancement upswing delay. Time-density curves were assessed for truncation and compared between the 2 groups, and the radiation dose was evaluated.

RESULTS

From September 2017 through May 2018, one hundred fifty-three patients underwent the standard fixed-timing protocol. Age (OR, 1.82/10-year increase; P = .019), reduced left ventricle ejection fraction (OR, 9.23; P = .001), and hypertension (OR, 0.32; P = .06) were independently associated with truncation in an exploratory multivariable model. From May 2018 through April 2019, one hundred fifty-seven patients underwent either the standard (72 patients) or low cardiac output protocol (85 patients). The fixed-timing cohort had 15 truncations (9.8%) versus 4 in the case-specific cohort (2.5%; P = .009). If the low cardiac output protocol were applied to those with >10.6% predicted risk of truncation based on age, left ventricle ejection fraction, and hypertension, the number of truncations would have decreased from 15 to 4 in the fixed-timing cohort.

CONCLUSIONS

Older age, left ventricle ejection fraction, and the absence of hypertension increase the risk of time-density curve truncation. However, a CTA test-dose-directed case-specific protocol can reduce truncation to ensure accurate data while mitigating radiation dose increases.

Pro- and anti-apoptotic activities of protozoan parasites

During infection, programmed cell death, i.e. apoptosis, is an important effector mechanism of innate and adaptive host responses to parasites. In addition, it fulfils essential functions in regulating host immunity and tissue homeostasis. Not surprisingly, however, adaptation of parasitic protozoa to their hosts also involves modulation or even exploitation of cell death in order to facilitate parasite survival in a hostile environment. During recent years, considerable progress has been made in our understanding of apoptosis during parasitic infections and there is now convincing evidence that apoptosis and its modulation by protozoan parasites has a major impact on the parasite-host interaction and on the pathogenesis of disease. This review updates our current knowledge on the diverse functions apoptosis may fulfil during infections with diverse protozoan parasites including apicomplexans, kinetoplastids and amoebae. Furthermore, we also summarize common mechanistic themes of the pro- and anti-apoptotic activities of protozoan parasites. The diverse and complex effects which parasitic protozoa exert on apoptotic cell death within the host highlight fascinating interactions of parasites and their hosts. Importantly, they also stress the importance of further investigations before the modulation of host cell apoptosis can be exploited to combat parasitic infections.