Prevalence and Predictors of Sexual Dysfunction (SD) after Treatment of Localized Rectal and Anal Cancer (LRAC)

PURPOSE/OBJECTIVE(S)

SD is possible after treatment of LRAC and is associated with distress and impaired quality of life. We report the prevalence of SD in our LRAC patients treated with curative intent. We also evaluate patient/treatment-related factors associated with SD.

MATERIALS/METHODS

LRAC patients from 2010-2022 were identified. Consented patients were surveyed and patient/treatment factors were collated from medical records. Sexual function (SF) was measured using the Female Sexual Function Index (FSFI) and the International Index of Erectile Function (IIEF). The impact of disease/treatment on SF since treatment was measured using the SF Questionnaire Medical Impact Scale (SFQ-MIS). FSFI ≤ 19.2 and IIEF ≤ 32.2 were considered SD based on the mean scores of SD patients in the primary literature. SFQ-MIS ≥ 15.5 was used to dichotomize responses into "at least some impact" versus "at least no impact." Spearman rank correlations examined correlations between FSFI/IIEF and factors. Comparisons involving componential domains and factors were based on a two-sided Mann-Whitney test. RT dose, surgery, the extent of lymphadenectomy, T stage, and time since treatment were factors assessed in all patients. In females, dilator use during RT, tumor distance (TD) from the anterior vaginal wall and whole vagina, and V25Gy, V45Gy, and mean dose to the anterior vaginal wall and whole vagina were other factors assessed. In males, TD from the neurovascular bundle (NVB), V25Gy, V45Gy, and mean dose to NVB was used.

RESULTS

Forty-five patients (13.5% response rate) completed study surveys (62% males; 80% white; 71% rectal cancer patients). The median age and time since treatment were 63 and 4 yrs. respectively. RT doses ranged from 25 - 54Gy. The overall prevalence of SD was 58% (71% in females; 50% in males). The proportion of patients who reported at least some SF impact was 56% (53% in females; 57% in males). There was a marginal association between higher total IIEF and receipt of surgery (p = 0.059). A correlation of 0.44 was seen between total IIEF and TD from upper NVB-the strongest among all comparisons. In the domains of IIEF, statistically significant associations were found between intercourse satisfaction (ISAT) and TD from upper NVB (p = 0.004), overall satisfaction (OSAT) and TD from lower NVB (p = 0.040), and ISAT and T stage (p = 0.047). There were marginal associations between TD from upper NVB and OSAT (p = 0.052), orgasm (p = 0.063), and erectile dysfunction (p = 0.097). There was a marginal association between V25Gy to the anterior vaginal wall and pain during penetrative sex (p = 0.095). No other association with FSFI or its domains was significant.

CONCLUSION

SD is prevalent in a large majority of patients studied (58%). In males, higher TD from NVB was associated with better overall SF, better intercourse, and overall satisfaction. While a higher proportion of females had SD, no significant associations were found in females likely due to their small sample size.

Systematic Review of Comparisons Between Plastic and Silicone Dilators: Revealing a Knowledge Gap

INTRODUCTION

Vaginal stenosis is a distressing side effect of radiation therapy that can impair quality of life. Dilator therapy is an option for patients undergoing pelvic radiotherapy to mitigate vaginal stenosis. Currently, the dilators given to patients by most hospitals are made of plastic, compared to silicone dilators which are available on the market for purchase.

OBJECTIVES

We conducted a systematic literature review to find information to guide clinical recommendations to pelvic radiotherapy patients on potential differences regarding the use of plastic vs silicone dilators with regard to efficacy, cost, and patient preferences.

METHODS

A systematic literature review was conducted in Embase, MEDLINE, and PubMed using Emtree terms. To be included in the review, papers needed to: focus on female patients undergoing radiation therapy, assess a vaginal dilator, measure any dilator intervention outcome, and specifically compare plastic vs silicone dilators for any measured outcome (either qualitative or quantitative).

RESULTS

The initial search yielded 195 articles. Two area experts, with a third expert for arbitration, read each article and found that none met all review inclusion criteria. No studies were found that compared silicone to plastic dilators with regard to efficacy in treating vaginal stenosis due to radiation therapy, no studies were found that compared cost or cost-effectiveness of the 2 dilator types, and no studies were found comparing patient preferences or experiences (eg, comfort, adherence, ease of use) between the 2 dilator types.

CONCLUSION

The materials used to create dilators have never been rigorously compared in the context of radiotherapy-related vaginal stenosis. Institutions and patients have no data to guide their choice. Significantly more research at the patient and institutional level is needed to explore the potential long-term quality of life and cost benefits of improved adherence with silicone dilator use, and to guide shared decision-making regarding dilator choice. Morgan O, Lopez MD, Martinez AJC, et al. Systematic Review of Comparisons Between Plastic and Silicone Dilators: Revealing a Knowledge Gap. Sex Med Rev 2022;10:513-519.

Development of formulations to improve the controlled-release of linalool to be applied as an insecticide

In recent studies, insecticide activity of a monoterpene, linalool, has been demonstrated, finding, however, limitations in application because of its rapid volatilization. Potential effectiveness of microcapsules and effects of various types of matrices on its stability as controlled-release systems for the slow volatilization of linalool to be applied as insecticide were evaluated. To study controlled-release, linalool was entrapped into microcapsules, inclusion complexes, and beads, obtained by different methods, inverse gelation (IG1, IG2, IG3, IG4, and IG5), oil-emulsion-entrapment (OEE), interfacial coacervation (INCO), and chemical precipitation (Cyc5 and Cyc10). The encapsulation yield turned out to be different for each formulation, reaching the maximum retention for IG1 and OEE. In controlled-release, OEE followed by INCO presented a long time necessary for releasing as a result of the presence of glycerol or chitosan. These results pointed out remarkable differences in the release behavior of linalool depending on matrix composition and the method of encapsulation.

Temperature-dependent production of marine copepods: a global synthesis

Estimating the production of marine copepods depends on measuring two key variables: biomass and growth rate. The major difficulty in estimating production of marine copepods and other zooplankton has been the inability to obtain precise, rapid measurements. In practice the variability in measurement of biomass greatly exceeds that in growth rate. It is shown here that individual growth rates of copepods can be accurately estimated from data on generation times and the weights of eggs and adults. Analysis of 181 separately published estimates of generation time for 33 species of copepods at environmental temperatures ranging from -1.7 degrees to 30.7 degrees C shows that temperature alone explains more than 90% of the variance in growth rate. Temperature dependence of growth rate transcends species differences. Weight-specific growth rate appears to be independent of body size. We hypothesize that food may not be limiting to growth in nature; the impression that food is limiting may be due to sampling at the wrong scales. Another possible cause of the apparent maximum growth rates of copepods in nature is predation mortality, which could selectively remove slower-growing individuals from the population. The temperature-dependent model developed here predicts the phenomenon of decreasing body size with increasing environmental temperature, often observed for single species of copepods. A method is suggested for making more accurate estimates of secondary production by using modern instrumentation to make quasi-synoptic measurements of biomass and temperature and using the temperature-dependent model to estimate individual growth rates.

Top predators in the Southern ocean: a major leak in the biological carbon pump

Primary productivity in the Southern Ocean is approximately 3.5 gigatons of carbon per year, which accounts for nearly 15 percent of the global total. The presence of high concentrations of nitrate in Antarctic waters suggests that it might be possible to increase primary production significantly and thereby alleviate the net accumulation of atmospheric carbon dioxide. An analysis of the food web for these waters implies that the Southern Ocean may be remarkably inefficient as a carbon sink. This inefficiency is caused by the large flux of carbon respired to the atmosphere by air-breathing birds and mammals, dominant predators in the unusually simple food web of Antarctic waters. These top predators may transfer into the atmosphere as much as 20 to 25 percent of photosynthetically fixed carbon.