Oncofertility and Cancer Statistics in Canada

Oncofertility

• Cancer treatment can impact fertility
• Fertility was overlooked in cancer patients previously
• Oncofertility is a new interdisciplinary field
• It bridges oncology and reproductive medicine
• Oncology deals with cancer prevention, diagnosis, and treatment
• Reproductive medicine deals with reproductive health
• Cancer is abnormal and malignant cell growth
• Cancer cells are difficult to distinguish from normal cells
• Cancer treatment often affects normal cells, tissues, and organs
• Malignant tumors aggressively invade other tissues
• Benign tumors do not spread

Cancer Statistics in Canada

• 206,200 new cancer cases
• 80,800 cancer deaths in 2017
• Prostate cancer accounts for 21% of new cases in men
• Breast cancer accounts for 25% of new cases in women
• 1 in 2 people are expected to develop cancer in their lifetime

Impact of Childhood Cancer

• Childhood cancer accounts for less than 1% of all new cancer cases
• Top 3 types are leukemia, brain/CNS cancer, and lymphoma
• It's the leading cause of disease-related death in children
• Treatments have a significant impact on future fertility
• Clinicians balance treatment benefits with future wellbeing

Effect of Cancer Treatments on Fertility

• Treatment choices depend on cancer type and individual factors
• Combination therapy is common
• Surgery can damage reproductive organs
• Chemotherapy can damage DNA (temporary or permanent)
• Radiation damages DNA, causing cell necrosis
• Hormone therapy may cause temporary fertility loss
• Immunotherapy and targeted therapy have unknown long-term fertility effects

Fertility Preservation in Cancer Patients

• Patients sometimes choose less effective cancer treatments to reduce infertility risk
• Methods to preserve fertility involve gonadal shielding and cryopreservation
• Gonadal shielding protects reproductive organs during radiation
• Cryopreservation freezes gametes or embryos for later use
• Assisted reproductive technologies (ARTs) are used for fertility restoration

Cryopreservation Damage

• Dehydration/osmotic damage: Increased solute concentration and ion exchange disruption
• Mechanical changes: Membrane folding, electrochemical gradient alterations, and enzyme activity changes
• Rehydration damage: Lysis of damaged cells and electrolyte loss
• Oxidative stress: Free radical damage and lipid peroxidation
• Temperature stress: Protein denaturation and ice crystal formation

Ovarian tissue cryopreservation

• Preservation of ovarian tissue, follicles, or strips of tissue
• Tissue transplantation, or IVF-follicle maturation
• Less preferred approach, risk of reintroducing cancer cells

Oocyte Cryopreservation

• Hormonal stimulation before oocyte retrieval
• Oocytes collected via transvaginal oocyte retrieval
• Cryopreserved oocytes can be thawed and fertilized
• Ideal when no sperm donor/partner is available
• More complex approach

Embryo Cryopreservation

• Hormonal stimulation for multiple oocyte maturation
• Collected oocytes are fertilized in vitro
• Embryos are cryopreserved
• Ideal for post-pubertal women

Cryopreservation in Males

• Sperm retrieval methods
• Useful for pre-pubertal boys
• Sperm preservation is less complex than in women

Guidelines for Oncologists

• 2016 guidelines from The American Society of Clinical Oncology
• Aim to provide oncologists with best practices for fertility preservation in cancer patients

Latest Advances in Oncofertility

• Consistent reports of insufficient information about fertility given to patients
• Only 18-26% of at-risk adolescents cryopreserve sperm
• Survivor care plans often lack comprehensive counseling
• The Oncofertility Consortium advocates for improved fertility support

Embryo Editing Technologies

• Assisted reproductive technologies (ARTs) allow for embryo access/manipulation before implantation
• Ethical concerns have arisen surrounding embryo editing technologies
• Issues include recurrent miscarriage rates, aneuploidy concerns, and the selection of embryos without hereditary diseases
• Techniques used include preimplantation genetic diagnosis (PGD) and preimplantation genetic screening (PGS)
• PGD and PGS select embryos with normal genetic makeup, rather than modifying them directly

Direct Genome Editing with CRISPR/Cas9

• CRISPR/Cas9 is a powerful genome editing tool
• It's more efficient and precise than previous methods
• Potential for gene editing in embryos
• Significant ethical concerns, including large-scale consequences and misuse of the technology

Ethics of Embryo Manipulation

• Ethical considerations surrounding reproductive technologies, including selection and modification of embryos
• Concerns about the impact on subsequent generations
• Issues include selection of traits, reinforcement of prejudice, and human genome modification

Transgenerational Health

• Assisted reproductive technologies affect health in subsequent generations
• Influence of uterine environment on future health
• Barker's Hypothesis: Birth weight and heart disease in adulthood
• DOHaD Theory: Influences of the uterine environment on future health

This quiz explores the intersection of cancer treatment and fertility, an emerging field known as oncofertility. It highlights important cancer statistics in Canada, including prevalent types of cancer and their impact on patients. Additionally, the implications of childhood cancer are discussed, providing a comprehensive overview of cancer effects on reproductive health.