P–433 Pregnancy and livebirth after fertility preservation in cancer patients

Study question

What do we know about pregnancy and livebirth after IVF- fertility preservation treatment in women with cancer?

Summary answer

Most women conceived spontaneously (60%) and more than 50% of those who returned to use their cryopreserved reproductive material have delivered at least one child.

What is known already

Diminishing ovarian reserve and declining future reproductive potential are important issues in cancer survivors after anti-cancer treatment exposure. Publications on pregnancy and livebirth after fertility preservation in women with cancer are sparse. Studies report most cancer patient who underwent fertility preservation do not come back and use their frozen reproductive material. The purpose of this study was to investigate the fertility preservation outcome among cancer survivors.

Study design, size, duration

A retrospective cohort study was conducted at a single academic fertility center from including 336 cancer patients who underwent IVF-fertility preservation from January 2009 to June 2020.

Participants/materials, setting, methods

We included all women with cancer aged ≤40 years old who were referred for fertility preservation treatment prior to chemotherapy.

Primary outcome: Number of pregnancies and livebirths after spontaneous conception and/or using their stored frozen material.

Secondary outcomes: We also evaluated the utilization rate of the stored reproductive material and mortality rate among those with follow up data.

Main results and the role of chance

Of 336 patients who underwent IVF-fertility preservation, 214 (63.69%) elected oocyte cryopreservation, 86 (25.5%) underwent both embryo and oocyte cryopreservation and 36 (10.7`%) underwent embryo cryopreservation. Follow up data were available in 198 (58.9%) patients with a mean follow up of 3.2 years. Of 198, 16 (8%) patients died, 40 (20%) became pregnant. Of those pregnant patients, 24 (60%) became spontaneously pregnant and 16 (40%) became pregnant after frozen oocyte or frozen embryo treatment cycles. Almost a quarter (72.5%) of the pregnancies resulted in livebirths. In total, only 23 (7%) patients had returned for frozen oocyte or frozen embryo treatment cycle, of which 16 (70%) achieved a pregnancy and 10 (63%) achieved at least one live birth. Of 142 patients who were still alive at follow up but did not get pregnant, 51 (39%) were in remission from their cancer but had not chosen to use their stored reproductive material; 44 (31%) were still on anti-cancer treatment and had not started trying yet; 13 (9%) were suffering from the end-stage cancer disease; and 7 (5%) had used their stored reproductive material but failed and stopped trying to get pregnant.

Limitations, reasons for caution

The main limitation was the retrospective cohort study design which could introduce unidentified selection biases.

Wider implications of the findings: Of women who underwent IVF-fertility preservation for cancer, most did not come back for treatment for a variety of reasons. Of those who became pregnant, 60% conceived spontaneously. Of those who used their cryopreserved reproductive material, 63% delivered at least one child.

Trial registration number

2021/6935

Application of a prediction model for work-related sensitisation in bakery workers

Identification of work-related allergy, particularly work-related asthma, in a (nationwide) medical surveillance programme among bakery workers requires an effective and efficient strategy. Bakers at high risk of having work-related allergy were indentified by use of a questionnaire-based prediction model for work-related sensitisation. The questionnaire was applied among 5,325 participating bakers. Sequential diagnostic investigations were performed only in those with an elevated risk. Performance of the model was evaluated in 674 randomly selected bakers who participated in the medical surveillance programme and the validation study. Clinical investigations were evaluated in the first 73 bakers referred at high risk. Overall 90% of bakers at risk of having asthma could be identified. Individuals at low risk showed 0.3-3.8% work-related respiratory symptoms, medication use or absenteeism. Predicting flour sensitisation by a simple questionnaire and score chart seems more effective at detecting work-related allergy than serology testing followed by clinical investigation in all immunoglobulin E class II-positive individuals. This prediction based stratification procedure appeared effective in detecting work-related allergy among bakers and can accurately be used for periodic examination, especially in small enterprises where delivery of adequate care is difficult. This approach may contribute to cost reduction.

Wheat allergen exposure and the prevalence of work-related sensitization and allergy in bakery workers

BACKGROUND

Occupational airway diseases are common among bakers. The present study describes the association between exposure to wheat allergen levels and sensitization to wheat allergens, work-related upper and lower respiratory symptoms and asthma in bakery workers.

METHODS

As part of a Health Surveillance System for early detection of (allergic) occupational airway diseases a so-called 'validation study' was performed among Dutch bakers for validation of a diagnostic model that predict the likelihood of sensitization to specific workplace allergens. The present study used serology and questionnaire results of a subgroup of 860 bakers participating in the validation study. An earlier developed job-exposure matrix was used to predict average and cumulative personal exposure to wheat allergens.

RESULTS

The prevalence of wheat sensitization, work-related respiratory symptoms and asthma increased till average wheat exposure levels of approximately 25-30 microg/m3, leveled off and decreased at higher exposure concentrations. Exposure-response curves showed a stronger pronounced bell-shape with cumulative exposure. Associations were strongest for asthma and work-related lower respiratory symptoms (PR approximately 2 and PR approximately 3.5-4.5 for average and cumulative exposure, respectively). Associations were only found in atopics. Wheat sensitization was an important factor in the prevalence of respiratory symptoms.

CONCLUSION

In accordance with earlier studies, the present study showed a bell-shaped exposure-response relationship especially for cumulative wheat allergen exposure with sensitization, allergic respiratory symptoms and asthma. The healthy worker effect may be the possible explanation for the bell-shaped relationship.

Risks for the development of outcomes related to occupational allergies: an application of the asthma-specific job exposure matrix compared with self-reports and investigator scores on job-training-related exposure

BACKGROUND AND AIM

Risks for development of occupational sensitisation, bronchial hyper-responsiveness, rhinoconjunctival and chest symptoms at work associated with continued exposure to high molecular weight (HMW) allergens were estimated with three exposure assessment methods.

METHODS

A Cox regression analysis with adjustment for atopy and smoking habit was carried out in 408 apprentices in animal health technology, pastry making, and dental hygiene technology with an 8-year follow-up after training. The risk of continued exposure after training, estimated by the asthma-specific job exposure matrix (JEM), was compared with self-reports and investigator scores on job-training-related exposure. Associations between outcomes and work duration in job(s) related to training were also evaluated.

RESULTS

Exposure to animal-derived HMW allergens, subsequent to the apprenticeship period, as estimated by the JEM, was associated with a significantly increased risk for occupational sensitisation (hazard ratio (HR) 6.4; 95% CI 2.3 to 18.2) and rhinoconjunctival symptoms at work (HR 2.6; 95% CI 1.1 to 6.2). Exposure to low molecular weight (LMW) agents significantly increased the risk of developing bronchial hyper-responsiveness (HR 2.3; 95% CI 1.1 to 5.4). Exposure verification appeared to be important to optimise the sensitivity and the specificity, as well as HRs produced by the JEM. Self-reports and investigator scores also indicated that further exposure to HMW allergens increased the risk of developing occupational allergies. The agreement between self-reports, investigator scores, and the JEM were moderate to good. There was no significant association between respiratory outcomes and work duration in jobs related to training.

CONCLUSION

The asthma-specific JEM could estimate the risk of various outcomes of occupational allergies associated with exposure to HMW and LMW allergens, but it is relatively labour intensive. Exposure verification is an important integrated step in the JEM that optimised the performance of the matrix.

Which tools best predict the incidence of work-related sensitisation and symptoms

BACKGROUND/AIM

This study used information from the questionnaire alone or in conjunction with clinical tests, such as skin-prick testing (SPT) and bronchial responsiveness (BR) testing at entry, to develop models for estimating the probability of the occurrence of specific IgE-sensitisation to and respiratory symptoms in contact with laboratory animal (LA) allergens after 32 months' training in an animal health technology programme.

METHODS

Four multivariable logistic regression models were developed for each endpoint, consisting of: (1) questionnaire; (2) questionnaire and SPT; (3) questionnaire and BR testing; and (4) questionnaire, SPT and BR testing. The prognostic models were derived from a cohort of Canadian animal health technology apprentices. The models' internal validity and diagnostic accuracy were evaluated and compared.

RESULTS

Symptoms indicative of asthma and allergic symptoms at baseline composed the final questionnaire model for the occurrence of occupational sensitisation and symptoms. Both questionnaire models showed a good discrimination (area under the receiver operating characteristics curve were 0.73 and 0.78, respectively) and calibration (Hosmer-Lemeshow test p value >0.10). Addition of SPT and/or BR testing increased the specificity of the questionnaire model for LA sensitisation, but not for symptoms at work. To facilitate their application in practice, the final questionnaire models were converted to easy-to-use scoring system.

CONCLUSIONS

Questionnaire is an easy tool that can give accurate prediction of the incidence of occupational sensitisation and symptoms.