Changes

December 2024 — reviewed. A literature search was conducted from November to December 2024 to identify evidence-based guidelines, UK policy, systematic reviews, and key randomized controlled trials published since the last revision of the topic. Recommendations have been updated in line with current evidence. Minor changes have been made with regards to referral in line with the latest NHS England guidance Newborn and infant physical examination (NIPE) screening programme handbook.

Update

Goals

To support primary healthcare professionals to:

• Be aware when to suspect undescended testes.
• Differentiate between an undescended testis and a retractile testis, where possible.
• Arrange prompt referral to secondary care for ongoing management.

Outcome measures

Audit criteria

QOF indicators

QIPP - Options for local implementation

NICE quality standards

What is it?

• Undescended testes, or cryptorchidism, is defined as the incomplete descent of one or both testes from the abdomen through the inguinal canal, with a resultant absence from the scrotum [AUA, 2018; Leslie, 2024; NHS England, 2024].
  • It may be bilateral in up to 30% of cases [EAU, 2024].
  • About 80% of all undescended testes are palpable [EAU, 2024].
• Undescended testes can be classified as [EAU, 2024]:
  • Palpable
    • True undescended testis — the testis lies along the normal path of descent in the abdomen or inguinal region but has never previously been present in the scrotum.
    • Ectopic testis — the testis lies outside of the normal path of descent and outside the scrotum, for example, in the femoral region, perineum, penile shaft, or opposite hemiscrotum. The most common position is the superficial inguinal pouch. Usually, if ectopic, the testis will not descend to the correct position spontaneously.
    • Retractile testis — the testis has completed the descent into the correct position but may be found above the scrotum along the normal path of descent. The testis can be manipulated easily down to the scrotum and remains there for some time.
  • Non-palpable
    • True undescended testis (inguinal or intra-abdominal).
    • Ectopic testis.
    • Absent or atrophic testis — the testis may be missing or 'vanishing' (seen in the scrotum at birth but later disappears), causing a non-palpable testis. Possible mechanisms include testicular atrophy after intrauterine torsion, and agenesis due to failed development of the testicular blood supply.
• Undescended testes may also be classified as [AUA, 2018; EAU, 2024]:
  • Congenital — testis not present from birth.
  • Acquired — the testis is intrascrotal at birth, but subsequently found in an extrascrotal position.
    • Ascending testis — the testis has previously been present in the scrotum but has then moved to a higher position over time, and no longer lies in the scrotum. This may be due to a persisting processus vaginalis (fibrous remnant), which prevents elongation of the testicular vessels and vas deferens, causing secondary ascent of the testis. It is also a possible complication of inguinal hernia surgery in children.

What causes it?

• The cause of undescended testes is currently not known, but it is believed to be due to a combination of genetic, maternal, and environmental factors, leading to a disruption in the normal hormonal and physical processes of testicular descent during gestation.
• • Normally, there is a migration of the testes from a retroperitoneal position near the kidneys to the final scrotal position. This normally occurs in two stages, firstly at 8–15 weeks gestation and subsequently at 25–35 weeks of gestation. The second stage is androgen-dependent.
  • Any abnormality in the hormonal control or anatomical processes involved may cause undescended testes.
  • Studies show familial clustering in some cases, suggesting that there may be an underlying genetic association.
  • A specific cause or defect is rarely identified.
• Rarely, it may be associated with a disorder of sexual development.
  • Chromosomal abnormalities that cause congenital hypogonadism and a lack of androgen production.
  • Mutations of the androgen receptor gene resulting in androgen insensitivity.

 [Yeap, 2019; BMJ Best Practice, 2022; Hutson, 2022; Leslie, 2024]

What are the risk factors?

• Risk factors for undescended testes include:
  • A first-degree family history of undescended testes (baby's father or sibling). This may be present in up to 23% of cases.
  • Low birth weight (under 2.5 kg) and/or small for gestational age. 
  • Preterm delivery (earlier than 37 weeks gestation). Cryptorchidism at birth in premature babies may resolve when adjusted for gestational age.
  • Certain genetic syndromes, such as Prader-Willi syndrome, Prune belly syndrome, or congenital adrenal hyperplasia.
  • Disorders of sexual development.
• Weaker possible risk factors may include: 
  • Maternal smoking.
  • Maternal alcohol use during pregnancy.
  • Maternal diabetes (gestational or pre-gestational).
  • Environmental exposure to some chemicals (organochlorines, [such as polychlorinated biphenyls], environmental oestrogens, phthalate esters, bisphenol-A, pesticides, and analgesics.) Studies reporting these risks are conflicting and difficult to interpret with confidence. 
  • Previous inguinal hernia surgery — increased risk of ascending testis.
  • A history of retractile testis — increased risk of ascending testis.

[AUA, 2018; Cho, 2019; BMJ Best Practice, 2022; NHS England, 2024]

How common is it?

• Undescended testes are one of the most common congenital malformations of male neonates.
• Incidence varies depending on gestational age, but the condition appears to affect 1–4.6% of full-term and 1.1–45% of preterm neonates.
• Both sides are affected in up to 30% of cases.
• Around 80% of undescended testes are palpable.
• Monorchidism (one absent testis) is found in up to 4% of all boys with undescended testes, and anorchidism (bilateral absence) is found in less than 1%.
• The relative proportion of cases of true testicular ascent (acquired cryptorchidism) as opposed to congenital cases that were not identified at birth remains unclear in the literature.

[Sijstermans, 2007; AUA, 2018; EAU, 2024]

What are the complications?

Possible complications of undescended testes include:

• Impaired fertility
  • There is an association between a history of undescended testes and reduced fertility. The lower temperature of the scrotum allows normal testicular physiology after birth. Undescended testes that remain in the abdomen, inguinal canal, or groin at a higher temperature may result in germ cell damage. This affects their transformation into stem cells for subsequent spermatogenesis and may result in reduced fertility rates. The effect is greater if both testes are undescended, and multiple factors may be involved, including germ cell loss, impaired germ cell maturation, Leydig cell diminution, and testicular fibrosis.
  • The fertility rate (number of offspring born per mating pair) and paternity rate (percentage of men who successfully achieve conception) vary with the location and cause of undescended testis.
  • Boys with unilateral undescended testis have a subsequent lower fertility rate but a similar paternity rate to those with normally descended testes (approximately 90% vs 94%). Those with bilateral undescended testes have lower fertility rates and lower paternity rates later in life (paternity rates 33–53%).
  • Earlier surgical correction improves subsequent fertility potential. 
• Testicular cancer
  • Cryptorchidism is a significant risk factor for testicular cancer.
  • There is variation in the estimation of risk within the literature. Those who do not have surgical correction, or who are treated over the age of 10, have been found to have a six-fold increased risk of testicular cancer. Those who have had treatment before puberty still have approximately two-fold increased risk, but still significantly less than those who have not had early treatment.
  • The risk is higher in cases of bilateral undescended testes. The chance of later testicular cancer is around 1 in 120 for those born with unilateral undescended testes, and around 1 in 44 for those with the bilateral condition.
  • The risk is highest in those with intra-abdominal testes, and the risk increases with the height of the testis within the abdomen.
  • Evidence suggests that surgical correction in the first year of life is more protective than later treatment. The earlier before puberty the treatment, the more protective against malignancy.
• Testicular torsion
  • Undescended testes may be more likely to undergo torsion than scrotal testes.
• Inguinal hernia
  • An associated inguinal hernia may occur in some boys with undescended testes.

Successful surgical correction of undescended testes reduces the risk of, but does not prevent, these complications.

[AUA, 2018; BMJ Best Practice, 2022; Florou, 2023; EAU, 2024]

When should screening for undescended testes be performed?

• Screening for undescended testes should be carried out for male infants:
  • Within 72 hours of birth.
  • At 6–8 weeks of age.
• A re-examination should be carried out at 4–5 months of age if the testes have previously been found to be undescended, to assess for spontaneous descent.

How should I assess a suspected undescended testis?

If there is a suspected undescended testis:

• Ask the parent/carer about:
  • The mother's medical and obstetric history, including whether the baby or infant was born at term or pre-term.
    • In pre-term infants the testis may still be descending at the time of delivery.
    • At term, about 50% of infants will complete testicular descent by 12 weeks after birth.
  • Any other known risk factors, including any family history of undescended testes, genetic or endocrine disorders, or history of previous inguinal hernia surgery.
  • Whether the testis has ever been palpable in the scrotum.
    • If the testis is palpable during a warm bath, this may suggest a retractile testis (normal variant).
    • If the testis was present in the scrotum at birth but is no longer palpable, this may suggest an ascending testis.
    • If any lump has been noticed in another location, this may suggest an ectopic testis.
• Examine the infant or male lying down in a warm room with warm hands, if possible.
  • Explain to the parent why you are examining the genitalia and how this will be done. Ask them to comfort the child while he is being examined. Expose from the umbilicus to the knees.
  • Inspect the scrotum for symmetry, size, and colour.
  • Inspect the external genitalia to assess for any abnormalities that could suggest a disorder of sex development, including:
    • Atypical genitalia.
    • Hypospadias (penile abnormality — check the position of the urethral meatus).
    • Micropenis (defined as a stretched penile length of less than 2.5 standard deviations from the mean; less than 2 cm in the newborn).
    • Bifid or unfused scrotum.
    • Bilateral impalpable undescended testes.
    • Examine for secondary sex characteristics/signs of puberty in those presenting with cryptorchidism at an older age.
  • Palpate the scrotal sac on each side to assess whether the testis is in the proper scrotal position, its size, and consistency.
  • If the testis is not located in the scrotal sac and there is a suspected undescended testis, use the fingers to 'milk' from the external inguinal ring to the scrotum along the inguinal canal to try to palpate the testis. A lubricant may be helpful to reduce friction and make the testis easier to detect. 
    • A possible inguinal testis may 'bounce' under the fingers. Once located, assess whether the testis can be moved to the scrotum.
    • If it cannot be palpated or manipulated into the base of the scrotum, this suggests an undescended testis.
    • If it can be manipulated into the base of the scrotum, but retracts back to an inguinal position after a variable time following manipulation, this suggests a retractile testis.
    • Note: a non-palpable testis when the person is lying down may become palpable in the sitting or squatting position.
  • If there is a suspected unilateral non-palpable testis, examine the contralateral testis.
    • If there is compensatory hypertrophy of the contralateral testis, this suggests testicular absence or atrophy.
    • This may be assessed by comparing the scrotal testis to the glans penis, which is usually approximately the same size. Compensatory hypertrophy is likely if the scrotal testis is larger than the glans penis.
    • Bilateral undescended testes may suggest a disorder of sex development.
  • If the testis is not present in the scrotum or inguinal region, examine for an ectopic testis in the femoral, penile, and perineal regions.
• Do not arrange imaging investigations such as ultrasound in primary care if the testis is not palpable.

Scenario: Undescended testes

From birth onwards (Male).

Search strategy

Scope of search

A literature search was conducted for guidelines and systematic reviews on primary care management of undescended testes.

Search dates

January 2020 - December 2024

Key search terms

The terms listed below are the core search terms that were used for EBSCOhost MEDLINE (searched 23rd January 2020. These were combined with filters to identify guidelines, systematic reviews and primary care relevant literature in EBSCOhost MEDLINE. The strategy was adapted for The Cochrane Library databases. 

S4    S1 OR S2 OR S3 
S3    AB ( ((undescended or maldescended or ascending or retractile or ectopic) N3 (testes or testis or testicle*)) ) OR TI ( ((undescended or maldescended or ascending or retractile or ectopic) N3 (testes or testis or testicle*)) ) 
S2    AB cryptorchid* OR TI cryptorchid* 
S1    (MH "Cryptorchidism")

Sources of guidelines

• National Institute for Health and Care Excellence (NICE)
• Scottish Intercollegiate Guidelines Network (SIGN)
• Royal College of Physicians
• Royal College of General Practitioners
• Royal College of Nursing
• NICE Evidence
• World Health Organization
• Guidelines International Network
• TRIP database
• Agency for Healthcare Research and Quality
• Institute for Clinical Systems Improvement
• National Health and Medical Research Council (Australia)
• Royal Australian College of General Practitioners
• British Columbia Medical Association
• Canadian Medical Association
• Alberta Medical Association
• Michigan Quality Improvement Consortium
• Singapore Ministry of Health
• National Resource for Infection Control
• RefHELP NHS Lothian Referral Guidelines
• Medline (with guideline filter)
• Driver and Vehicle Licensing Agency
• NHS Health at Work (occupational health practice)

Sources of systematic reviews and meta-analyses

• The Cochrane Library:
  • Systematic reviews
  • Protocols
  • Database of Abstracts of Reviews of Effects
• Medline (with systematic review filter)
• EMBASE (with systematic review filter)

Sources of health technology assessments and economic appraisals

• NIHR Health Technology Assessment programme
• The Cochrane Library:
  • NHS Economic Evaluations
  • Health Technology Assessments
• Canadian Agency for Drugs and Technologies in Health
• International Network of Agencies for Health Technology Assessment

Sources of randomized controlled trials

• The Cochrane Library:
  • Central Register of Controlled Trials
• Medline (with randomized controlled trial filter)
• EMBASE (with randomized controlled trial filter)

Sources of evidence based reviews and evidence summaries

• Bandolier
• Drug and Therapeutics Bulletin
• TRIP database
• Central Services Agency COMPASS Therapeutic Notes

Sources of national policy

• Department of Health
• Health Management Information Consortium (HMIC)

Patient experiences

• Healthtalk
• BMJ - Patient Journeys

Sources of medicines information

The following sources are used by CKS pharmacists and are not necessarily searched by CKS information specialists for all topics. Some of these resources are not freely available and require subscriptions to access content.

• British National Formulary (BNF)
• electronic Medicines Compendium (eMC)
• European Medicines Agency (EMEA)
• LactMed
• Medicines and Healthcare products Regulatory Agency (MHRA)
• REPROTOX
• Scottish Medicines Consortium
• Stockley's Drug Interactions
• TERIS
• TOXBASE
• Micromedex
• UK Medicines Information

Stakeholder engagement

Our policy

The external review process is an essential part of CKS topic development. Consultation with a wide range of stakeholders provides quality assurance of the topic in terms of:

• Clinical accuracy.
• Consistency with other providers of clinical knowledge for primary care.
• Accuracy of implementation of national guidance (in particular NICE guidelines).
• Usability.

Principles of the consultation process

• The process is inclusive and any individual may participate.
• To participate, an individual must declare whether they have any competing interests or not. If they do not declare whether or not they have competing interests, their comments will not be considered.
• Comments received after the deadline will be considered, but they may not be acted upon before the clinical topic is issued onto the website.
• Comments are accepted in any format that is convenient to the reviewer, although an electronic format is encouraged.
• External reviewers are not paid for commenting on the draft topics.
• Discussion with an individual or an organization about the CKS response to their comments is only undertaken in exceptional circumstances (at the discretion of the Clinical Editor or Editorial Steering Group).
• All reviewers are thanked and offered a letter acknowledging their contribution for the purposes of appraisal/revalidation.
• All reviewers are invited to be acknowledged on the website. All reviewers are given the opportunity to feedback about the external review process, enabling improvements to be made where appropriate.

Stakeholders

• Key stakeholders identified by the CKS team are invited to comment on draft CKS topics. Individuals and organizations can also register an interest to feedback on a specific topic, or topics in a particular clinical area, through the Getting involved section of the Clarity Informatics website.
• Stakeholders identified from the following groups are invited to review draft topics:
  • Experts in the topic area.
  • Professional organizations and societies (for example, Royal Colleges).
  • Patient organizations, Clarity has established close links with groups such as Age UK and the Alzheimer’s Society specifically for their input into new topic development, review of current topic content and advice on relevant areas of expert knowledge.
  • Guideline development groups where the topic is an implementation of a guideline.
  • The British National Formulary team.
  • The editorial team that develop MeReC Publications.
• Reviewers are provided with clear instructions about what to review, what comments are particularly helpful, how to submit comments, and declaring interests.

Patient engagement

Clarity Informatics has enlisted the support and involvement of patients and lay persons at all stages in the process of creating the content which include:

• Topic selection
• Scoping of topic
• Selection of clinical scenarios
• First draft internal review
• Second draft internal review
• External review
• Final draft and pre-publication

Our lay and patient involvement includes membership on the editorial steering group, contacting expert patient groups, organizations and individuals.

Evidence exclusion criteria

Our policy

Scoping a literature search, and reviewing the evidence for CKS is a methodical and systematic process that is carried out by the lead clinical author for each topic. Relevant evidence is gathered in order that the clinical author can make fully informed decisions and recommendations. It is important to note that some evidence may be excluded for a variety of reasons. These reasons may be applied across all CKS topics or may be specific to a given topic.

Studies identified during literature searches are reviewed to identify the most appropriate information to author a CKS topic, ensuring any recommendations are based on the best evidence. We use the principles of the GRADE and PICOT approaches to assess the quality of published research. We use the principles of AGREE II to assess the quality of published guidelines.

Standard exclusions for scoping literature:

• Animal studies
• Original research is not written in English

Possible exclusions for reviewed literature:

• Sample size too small or study underpowered
• Bias evident or promotional literature
• Population not relevant
• Intervention/treatment not relevant
• Outcomes not relevant
• Outcomes have no clear evidence of clinical effectiveness
• Setting not relevant
• Not relevant to UK
• Incorrect study type
• Review article
• Duplicate reference

Organizational, behavioural and financial barriers

Our policy

The CKS literature searches take into consideration the following concepts, which are discussed at the initial scoping of the topic.

• Feasibility
  • Studies are selected depending on whether the intervention under investigation is available in the NHS and can be practically and safely undertaken in primary care.
• Organizational and Financial Impact Analysis
• Studies are selected and evaluated on whether the intervention under investigations may have an impact on local clinical service provision or national impact on cost for the NHS. The principles of clinical budget impact analysis are adhered to, evaluated and recorded by the author. The following factors are considered when making this assessment and analysis.
  • Eligible population
  • Current interventions
  • Likely uptake of new intervention or recommendation
  • Cost of the current or new intervention mix
  • Impact on other costs
  • Condition-related costs
  • In-direct costs and service impacts
  • Time dependencies
• Cost-effectiveness or cost-benefit analysis studies are identified where available. 

We also evaluate and include evidence from NICE accredited sources which provide economic evaluations of recommendations, such as NICE guidelines. When a recommended action may not be possible because of resource constraints, this is explicitly indicated to healthcare professionals by the wording of the CKS recommendation.

Declarations of interest

Our policy

Clarity Informatics requests that all those involved in the writing and reviewing of topics, and those involved in the external review process to declare any competing interests. Signed copies are securely held by Clarity Informatics and are available on request with the permission of the individual. A copy of the declaration of interest form which participants are asked to complete annually is also available on request. A brief outline of the declarations of interest policy is described here and full details of the policy is available on the Clarity Informatics website. Declarations of interests of the authors are not routinely published, however competing interests of all those involved in the topic update or development are listed below. Competing interests include:

• Personal financial interests
• Personal family interest
• Personal non-financial interest
• Non-personal financial gain or benefit

Although particular attention is given to interests that could result in financial gains or losses for the individual, competing interests may also arise from academic competition or for political, personal, religious, and reputational reasons. An individual is not obliged to seek out knowledge of work done for, or on behalf of, the healthcare industry within the departments for which they are responsible if they would not normally expect to be informed.

Who should declare competing interests?

Any individual (or organization) involved in developing, reviewing, or commenting on clinical content, particularly the recommendations should declare competing interests. This includes the authoring team members, expert advisers, external reviewers of draft topics, individuals providing feedback on published topics, and Editorial Steering Group members. Declarations of interest are completed annually for authoring team and editorial steering group members, and are completed at the start of the topic update and development process for external stakeholders.

Competing interests declared for this topic:

None.