Fertility-Preserving Treatments and Patient- and Parental Satisfaction on Fertility Counseling in a Cohort of Newly Diagnosed Boys and Girls with Childhood Hodgkin Lymphoma

Purpose: The purpose of this study is to evaluate the use of fertility-preserving (FP) treatments and fertility counseling that was offered in a cohort of newly diagnosed children with classical Hodgkin lymphoma (cHL). Methods: In this observational study, boys and girls with cHL aged ≤ 18 years with scheduled treatment according to the EuroNet-PHL-C2 protocol were recruited from 18 sites (5 countries), between January 2017 and September 2021. In 2023, a subset of Dutch participants (aged ≥ 12 years at time of diagnosis) and parents/guardians were surveyed regarding fertility counseling. Results: A total of 101 boys and 104 girls were included. Most post-pubertal boys opted for semen cryopreservation pre-treatment (85% of expected). Invasive FP treatments were occasionally chosen for patients at a relatively low risk of fertility based on scheduled alkylating agent exposure (4/5 testicular biopsy, 4/4 oocyte, and 11/11 ovarian tissue cryopreservation). A total of 17 post-menarchal girls (20%) received GnRH-analogue co-treatment. Furthermore, 33/84 parents and 26/63 patients responded to the questionnaire. Most reported receiving fertility counseling (97%/89%). Statements regarding the timing and content of counseling were generally positive. Parents and patients considered fertility counseling important (94%/87% (strongly agreed) and most expressed concerns about (their child’s) fertility (at diagnosis 69%/46%, at present: 59%/42%). Conclusion: Systematic fertility counseling is crucial for all pediatric cHL patients and their families. FP treatment should be considered depending on the anticipated risk and patient factors. We encourage the development of a decision aid for FP in pediatric oncology.</p

Infinite regular games in the higher-order pushdown and the parametrized setting

Higher-order pushdown systems extend the idea of pushdown systems by using a "higher-order stack" (which is a nested stack). More precisely on level 1 this is a standard stack, on level 2 it is a stack of stacks, and so on. We study the higher-order pushdown systems in the context of infinite regular games. In the first part, we present a k-ExpTime algorithm to compute global positional winning strategies for parity games which are played on the configuration graph of a level-k higher-order pushdown system. To represent those winning strategies in a finite way we use a notion of regularity for sets of higher-order stacks that relies on certain ("symmetric") operations to build higher-order stacks. The construction of the strategies is based on automata theoretic techniques and uses the fact that the higher-order stacks constructed by symmetric operations can be arranged uniquely in a tree structure. In the second part, we study the solution of games in the sense of Gale and Stewart where the winning condition is specified by an MSO-formula phi(P) with a parameter P subset of N. This corresponds to a three player game where the i-th round between the two original players is extended by the choice of the bit 1 or 0 depending on whether i is in P or not. We consider the case that the parameter can be constructed by some deterministic machine, a "parameter generator". We solve the parametrized regular games for parameters P given by two kinds of such generators, namely: higher-order pushdown automata and collapsible pushdown automata. In the third part, we study higher-order pushdown systems and higher-order counter systems (where the stack alphabet contains only one symbol), by comparing the language classes accepted by corresponding automata. For example, we show that level-k pushdown languages are level-(k+1) counter languages

Positional Strategies for Higher-Order Pushdown Parity Games

International audienc

Positional Strategies for Higher-Order Pushdown Parity Games

Abstract. Higher-order pushdown systems generalize pushdown systems by using higher-order stacks, which are nested stacks of stacks. In this article, we consider parity games defined by higher-order pushdown systems and provide a k-Exptime algorithm to compute finite representations of positional winning strategies for both players for games defined by level-k higher-order pushdown automata. Our result is based on automata theoretic techniques exploiting the tree structure corresponding to higher-order stacks and their associated operations.