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The "CUBED" App - a tool to assist UK podiatrists.

  • Writer: Ivan Bristow
    Ivan Bristow
  • 7 days ago
  • 5 min read

Background



Melanoma arising on the foot is a rare but serious skin malignancy often associated with a poorer prognosis due to diagnostic delays. Building on established clinical guidelines, a team of podiatry colleagues has developed the CUBED App. This free, innovative tool helps practitioners rapidly apply the mnemonic to suspicious foot lesions, assist in scoring and generate a tailored letter for the patient's General Practitioner (GP) to facilitate timely referral and specialist assessment, if the CUBED score is two or greater.




The Critical Challenge of Foot Melanoma



Melanoma remains the fifth most common cancer in the UK, with nearly 18,000 new diagnoses expected this year (Cancer Research UK). While often associated with sun exposure, the tumour can arise anywhere on the skin, including less-exposed areas like the foot.



Why the Foot Warrants Special Attention



The foot accounts for a significant portion of cases, between 3–15% of all melanomas [1], making it the most common primary cancer arising on the foot [2]. Crucially, research consistently demonstrates that lesions found on the foot are often linked to a poorer prognosis compared to those elsewhere [3-5], a trend particularly noted in patients with skin of colour [6]. This disparity is primarily attributed to:


  • Late Patient Recognition: Patients often overlook lesions in this area [7].

  • Diagnostic Delay: Subsequent delays in diagnosis by healthcare practitioners [8].


A Foundation in Research: The Need for New Guidelines


Recognizing this critical challenge, I collaborated with a team of dermatologists to develop and publish specific guidelines for the recognition of foot melanoma [9, 10]. Published in the Journal of Foot and Ankle Research, this article became the journal's most-accessed publication, accumulating over 320,000 views (2025) and has been translated into multiple languages [11].


While undertaking this research, it became clear that the widely-used ABCDE mnemonic [12] was often not suitable for plantar lesions due to their frequently atypical presentation [13, 14]. Relying solely on ABCDE in the clinic risked missing potential melanomas on the foot. In response, the authors developed a new, simple, and effective tool: the CUBED mnemonic [9].


The CUBED acronym graphic

The Original CUBED acronym [10]


This mnemonic was specifically designed for clinical use, offering practitioners a straightforward scoring system to confidently determine when a lesion is potentially suspicious and requires referral.



The CUBED App



Following the successful adoption of the CUBED acronym in clinical practice, and leveraging modern, accessible app-building platforms, the decision was made in 2024 to create a dedicated application. The CUBED App allows practitioners to rapidly score any clinical lesion encountered during a patient consultation. The app is not AI based nor a diagnostic tool, it purely administers the CUBED acronym and can generate a PDF referral letter for editing and use by the podiatrist.



App Development and Functionality


The app was developed and beta-tested by the core group of podiatrists. This involved creating a digital prototype to gather crucial feedback before refining the core functionality. Furthermore, legal advice was secured to ensure full compliance with current UK regulations and GDPR standards.



A screenshot of the cubed App


A screenshot of the App in development



How the App Works



The CUBED App is designed exclusively for professional use. Its key functionality streamlines the assessment and referral process:


  1. Registration: Podiatrists register with the service.

  2. Assessment: The user answers a series of simple 'Yes/No' questions based on the CUBED acronym (Figure 2 in the original text).

  3. Scoring: The app calculates the CUBED score.

  4. Action Prompt: If the score reaches a threshold of 2 or more, the app prompts the podiatrist to input specific lesion details (e.g., location, size, duration).

  5. Image Upload: There is an option to directly add supporting photographs from the mobile or tablet device.

  6. Automated GP Letter: The app transforms this data into a downloadable, suitably worded referral letter for the patient's GP to request a prompt assessment.


The app also includes a feedback mechanism to gain valuable insight into its clinical applicability and ease of use, under a research project devised by the development team, which is approved by the University of Salford.



Accessibility



The CUBED App is FREE and available for download on both the Apple and Google Play app stores.


Further Information: www.cubed.website



Acknowledgements



The CUBED app development was generously supported by a grant from the Royal College of Podiatry Trust.



The CUBED App Development Team are:


  • Sarah Bradshaw, Manchester (App coding and programmer)

  • Ivan Bristow, Bournemouth

  • Michelle Reynolds, Stockport

  • Jennifer Andrews, Manchester

  • Michelle Cullen, Manchester



References



  1. Bristow I, Acland K: Acral lentiginous melanoma of the foot: a review of 27 cases. J Foot Ankle Res 2008,1:11.

  2. Barnes B, Seigler H, Saxby T, Kocher M, Harrelson J: Melanoma of the foot.J Bone Joint Surg Am 1994, 76:892–898.

  3. Kuchelmeister C, Schaumburg-Lever G, Garbe C: Acral cutaneous melanoma in caucasians: clinical features, histopathology and prognosis in 112 patients. 2000, 143: 275–280.

  4. Sondermann W, Zimmer L, Schadendorf D, Roesch A, Klode J, Dissemond J: Initial misdiagnosis of melanoma located on the foot is associated with poorer prognosis. Medicine (Baltimore) 2016,95:e4332.

  5. Teramoto Y, Keim U, Gesierich A, Schuler G, Fiedler E, Tüting T, Ulrich C, Wollina U, Hassel JC, Gutzmer R, et al: Acral lentiginous melanoma: a skin cancer with unfavourable prognostic features. A study of the German central malignant melanoma registry (CMMR) in 2050 patients. Br J Dermatol 2018, 178:443–451.

  6. Stubblefield J, Kelly B: Melanoma in non-caucasian populations. Surg Clin North Am 2014, 94:1115–1126, ix.

  7. Richard MA, Grob JJ, Avril MF, Delaunay M, Gouvernet J, Wolkenstein P, Souteyrand P, Dreno B, Bonerandi JJ, Dalac S, et al: Delays in diagnosis and melanoma prognosis (I): the role of patients. Int J Cancer 2000, 89:271–279.

  8. Richard MA, Grob JJ, Avril MF, Delaunay M, Gouvernet J, Wolkenstein P, Souteyrand P, Dreno B, Bonerandi JJ, Dalac S, et al: Delays in diagnosis and melanoma prognosis (II): The role of doctors. Int J Cancer 2000, 89:280–285.

  9. Bristow I, de Berker D: Development of a practical guide for the early recognition of malignant melanoma of the foot and nail unit. J Foot Ankle Res 2010, 3.

  10. Bristow IR, de Berker DA, Acland KM, Turner RJ, Bowling J: Clinical guidelines for the recognition of melanoma of the foot and nail unit. J Foot Ankle Res 2010, 3.

  11. Bristow IR: The origins and evolution of podiatric dermatology, PhD Thesis. University of Southampton, Faculty of Health Sciences; 2011.

  12. Friedman RJ, Rigel DS, Kopf AW: Early detection of malignant melanoma: the role of physician examination and self-examination of the skin. CA Cancer J Clin 1985, 35:130–151.

  13. Metzger S, Ellwanger U, Stroebel W, Schiebel U, Rassner G, Fierlbeck G: Extent and consequences of physician delay in the diagnosis of acral melanoma. Melanoma Res 1998, 8:181–186.

  14. Albreski D, Sloan SB: Melanoma of the feet: misdiagnosed and misunderstood. Clin Dermatol 2009,27:556–563.




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