Chemo- or radiation-induced nausea and vomiting (CRVN) is one of the most frequent and feared side effects.

It is a symptom that is few or not at all evaluated. There is a significant discrepancy between the perception of the CRVN symptom by caregivers and the patient's own experience.

At present, there is no real consensus to manage CRVN with medication, and CRVN relief is also the subject of heterogeneous practices. The importance of primary prevention of CRVN, before starting the first treatment sequence, has been highlighted to optimize the action of antiemetic treatments and limit the risk of anticipated nausea and vomiting (NV).

The investigators' objective is to objectively assess the risk of CRVN in children/adolescents treated for cancer (and thus effectively prevent this symptom).

In France, around 2,500 cancers are diagnosed each year in children/adolescents (0-18 years) (INCa data for 2011-2014).

For around 90% of these cases, chemotherapy and/or radiotherapy are indicated. Today, pediatric onco-hematology teams are committed to both the efficacy of treatments (and continue the progress made over the last few the progress made in recent decades in terms of survival); and to optimize the quality of life. One of the key areas for improving patient experience is to reduce the toxicity of treatments, and to prevent and alleviate known side effects.

Among these toxicities, chemo- or radiation-induced nausea and vomiting (CRVN) are one of the most frequent and dreaded side effects.

In addition to the impact of nausea and vomiting (NV) on the quality of life of children/adolescents (possibly impacting therapeutic); CRVN can lead to serious metabolic complications (sometimes impacting optimal treatment).

Theoretical considerations:

Several publications have already described the mechanisms of CRVN. Various studies have highlighted individual factors (gender, age, etc.) influencing the occurrence of NV (including in children/adolescents); and a variable emetogenic potential depending on the type of chemotherapy or radiotherapy.

- Several studies have focused on the prevention and relief of CVRN, a major side effect of cancer treatment. The importance of primary prevention of CVRN, before starting the first treatment sequence, has been highlighted.

The interests are twofold: to optimize the action of antiemetic treatments (more effective preventively than after the onset of vomiting); and to limit the risk of anticipated NV during subsequent treatment sequences.

- Finally, several observations made in different pediatric oncohaematology units, have highlighted a significant discrepancy between caregivers' perception of the CVRN symptom and the patient's own experience. These studies also highlight the existence of NV assessment scales, validated in pediatrics, but little known by professionals and therefore rarely used.

In practice:

• Currently, in pediatric onco-hematology, there is no real management of CVRN. Each team refers to a "local" procedure, and its application is often "left" to the discretion of each caregiver (prescription "if necessary"). A review of practices and therapeutic recommendations of the Support Care Committee of the SFCE (Société Française de lutte contre les Cancers et Leucémies des Enfants et adolescents) have recently been published.
• Relief of CVRN using non-medicinal techniques (hypnosis, acupuncture, laser, aromatherapy...) is also a heterogeneous practice (depending on specific professional skills), not evaluated in pediatrics.

In this context, the investigators were interested in the primary prophylaxis of NV; and wondered how to objectively assess the risk of CVRN in children/adolescents treated for cancer (and thus effectively prevent this symptom).

To meet this need, the project aims to develop a multifactorial score for assessing the risk of CVRN in children/adolescents treated for cancer (PaNACHE score).

The questioning at the origin of this project focused on considering the "NV" symptom in its different dimensions (sensory- emotional-cognitive-behavioral), such as the "pain" symptom. This approach enables us to base on validated models for assessing and managing pain in children/adolescents, centered in particular on the self-assessment of "patient experience".

The PaNACHE score is based on :

Assessment of various factors (individual and/or treatment-related) influencing NV (some of which have already been described in the literature)

- Self-assessment of NV perceived by the children/adolescent using the BARF scale (BAxter Retching Faces). This scale, graded from 0 to 10, shows 6 increasingly nauseous faces. It has been validated in pediatrics.

It can be used by the child himself from the age of 4, or by a close adult who is usually present with the child during treatment.

Since several studies have highlighted a noticeable difference between the caregiver's perception of the CVRN symptom and the patient's own experience, the investigators feel it is important to take into account the child/adolescent's self-assessment of his or her feelings, and not simply the factual number of vomits and/or the caregiver's hetero-assessment of perceived nausea.

Inclusion Criteria:

• Treated in a pediatric onco-hematology center in the GOCE (Grand Ouest Cancer Enfant) inter-region;
• Receiving chemotherapy or radiotherapy;
• According to patient age :
• Minor (under 18 years): At least one parent has been informed of the protocol and has not expressed opposition to the child's participation in the study
• Adult (more than 18 years): Having received information about the protocol and not having expressed opposition to participating in the study

Exclusion Criteria:

• Patients or legal representatives with French understanding difficulties.
• Patients or legal representatives subject with legal protection (safeguard of justice, curatorship, guardianship) or deprived of liberty.

In the Grand Ouest region, around 400 children/adolescents (aged 0-18) are diagnosed with cancer every year.

A sample of 150 subjects is expected for this research (involving 5 of the 10 GOCE collaborating centers).

This sample will be used to create a score including around ten variables (Peduzzi 1995).

The distribution of the number of inclusions is adapted to the recruitment and activity (chemotherapy or radiotherapy) of each of the 5 centers participating in this study.