Conditions › Melanoma stage 1A / 1B
Stage 1A & 1B Melanoma Diagnosis and Monitoring in London
Stage 1A and 1B melanoma represent the earliest invasive stages of skin cancer, where abnormal melanocytes have spread into the dermis but remain thin and usually without significant spread. With timely diagnosis and complete surgical removal, prognosis is excellent. At Skinhorizon Dermatology London, we provide expert mole checks, excision, and ongoing monitoring to detect melanoma early and reduce future risks.
Call Us Book ConsultationUnderstanding Stage 1A / 1B melanoma
Stage 1 melanoma is considered early invasive melanoma. Unlike melanoma in situ, cancer cells have grown into the dermis but remain relatively thin and have not spread to lymph nodes or distant organs. Detecting melanoma at this stage offers the best chance of cure through surgical removal.
Differences between Stage 1A and 1B
- Stage 1A: The melanoma is ≤1.0 mm thick and shows no ulceration. The mitotic rate (cell division activity) is usually low.
- Stage 1B: The melanoma is either:
- 0.8–1.0 mm thick with ulceration, OR
- 1.0–2.0 mm thick with or without ulceration.
These distinctions are important because ulceration and greater thickness slightly increase the risk of recurrence and progression, influencing treatment and follow-up plans.
Symptoms of Stage 1A & 1B Melanoma
Stage 1 melanoma often presents as a suspicious mole or pigmented patch. Warning signs include:
- Changes in size, shape, or colour of a mole
- Irregular or blurred borders
- Variegated colours (brown, black, red, blue, or white)
- Asymmetry between two halves of the mole
- Itching, bleeding, or crusting
- A mole that looks different from the rest (“ugly duckling sign”)
Stage 1A & 1B Melanoma Diagnosis
Diagnosis requires:
- Dermatology assessment: Clinical examination and dermoscopy.
- Excision biopsy: Complete removal of the suspicious mole for histological examination.
- Pathology analysis: Determines Breslow thickness, ulceration, and mitotic activity, which guide staging.
Treatment of Stage 1A & 1B Melanoma
The cornerstone of treatment is surgery. This includes:
- Wide local excision: The melanoma is removed with a margin of normal skin (1 cm for most Stage 1 cases).
- Sentinel lymph node biopsy (SLNB): Considered for some Stage 1B melanomas, especially if other risk factors are present.
- No systemic therapy: Immunotherapy or targeted therapy is not usually required at this stage.
Prognosis of Stage 1A & 1B Melanoma
Stage 1 melanoma has an excellent outlook. The 5-year survival rate exceeds 95%, especially when treated promptly. The risk of recurrence or spread is low but not zero, which is why follow-up is important.
Living with Stage 1 melanoma
After treatment, most patients lead normal lives. Key aspects of long-term care include:
- Regular skin checks with a dermatologist
- Monthly self-examination of skin and lymph nodes
- Sun safety: daily sunscreen, protective clothing, avoiding sunburns
- Awareness of new or changing lesions
- Psychological support, as a cancer diagnosis can cause anxiety
Your first visit — what to expect
- History: Assessment of mole changes, sun exposure, and family history.
- Examination: Full-body skin check with dermoscopy.
- Investigations: Excision biopsy of any suspicious mole.
- Management plan: Wide excision and advice on follow-up.
- Long-term care: Education on self-monitoring and scheduled reviews.
Reviewed by: Dr Mohammad Ghazavi, Consultant Dermatologist
Skinhorizon Clinic, 4 Clarendon Terrace, Maida Vale, London W9 1BZ
Last reviewed: 22 August 2025
Early diagnosis of Stage 1 melanoma saves lives. Book your mole check at Skinhorizon Dermatology London for expert assessment and treatment.
Call Us Book ConsultationMelanoma Stage 1A / 1B FAQs
What is the survival rate for Stage 1 melanoma?
Stage 1 melanoma has an excellent prognosis, with over 95% 5-year survival when treated promptly.
Do I need chemotherapy for Stage 1 melanoma?
No. Chemotherapy, immunotherapy, or targeted therapy are not needed for Stage 1 melanoma. Surgery alone is curative in most cases.
How often should I have follow-up checks after Stage 1 melanoma?
Most patients are reviewed every 3–12 months for the first 2–3 years, then annually. Your dermatologist will personalise your schedule.
Can Stage 1 melanoma come back?
Recurrence is uncommon but possible. Regular follow-up and sun safety significantly reduce risk.
How is Stage 1B different from Stage 1A?
Stage 1A tumours are ≤1 mm thick without ulceration. Stage 1B tumours are slightly thicker (0.8–2 mm) and may show ulceration, which carries a higher recurrence risk.
