Anal Cancer Treatments

While Anal Cancer is a serious disease, patients can feel confident in the high cure rates (over 90% for early-stage anal cancer). Working with a world-leading Clinical Oncologist like Dr Andy Gaya can provide access to all the vital tools needed to fight cancer. He specialises in the treatment of gastrointestinal cancer, including anal cancer, and has access to the most advanced oncology treatments in the world.

Dr Gaya gives his anal cancer patients a highly comprehensive and completely personalised oncological care plan. Treatments in cancer are advancing rapidly and even for those diagnosed with late-stage anal cancer, Dr Gaya can discuss participation in clinical trials for innovative treatments like immunotherapy.

Open communication with your healthcare team is key to managing side effects and symptoms, which can be challenging for anal cancer patients. Dr Gaya is here to support patients in achieving the best outcomes

Taking control of Anal Cancer

When it comes to cancer treatment it is not a ‘one size fits all’ approach. Just as every person has a fingerprint unique to them, every patient’s cancer has its own unique “genetic fingerprint”. The first step in optimising cancer treatment is to understand the cancer’s “genetic fingerprint”.

Dr Gaya will organise a tumour analysis to uncover the unique genetic profile of the patient’s cancer. From here Dr Gaya can recommend – from the entire spectrum of conventional cancer treatments, newer advanced treatments, other medications, supplements and lifestyle modifications – to positively impact the patient’s quality of life and overall survival.

The treatment of anal cancer depends on its stage, size, and whether it has spread (learn more about how anal cancer is staged here ‘link back to ‘about anal cancer’’). The goal is to cure the cancer while preserving normal bowel and anal function as much as possible.

Stage 0 Anal Cancer treatments

Stage 0 anal cancer is also called Anal Intraepithelial Neoplasia (AIN). It refers to abnormal cells in the lining of the anus and is not technically cancer (but these abnormal cells have the potential to develop into cancer in the future).

Surgery (where the doctor removes the cancerous cells, often endoscopically) is the most common option for patients with AIN. For cancers that are only in one layer the procedures are called ‘Endoscopic Mucosal Resection’ or ‘Endoscopic Submucosal Dissection. This is usually all that is needed alongside ‘surveillance’ monitoring of the patient afterwards.

Stage I, II or III Anal Cancer treatments

Chemoradiotherapy (CRT) is the primary approach for cancers in stages 1, 2 or 3. The aim is to cure the cancer by targeting the primary tumour and lymph nodes. CRT means a combination of chemotherapy (anti-cancer drugs) and radiation therapy (high-energy rays) that work together to destroy cancer cells. Chemotherapy makes cancer cells more sensitive to radiation, increasing its effectiveness.

In fact, CRT is so effective in curing anal cancer, that surgery is rarely needed. There is a huge body of medical evidence that reinforces the superiority of CRT alone in fighting anal cancer – maximising cure rates with minimal impact on quality of life.

Chemotherapy drugs

Mitomycin is a type of chemotherapy drug used to treat various types of cancer, including anal cancer, in combination with other chemotherapy drugs and radiotherapy. It is given as an injection on the first day of treatment and enhances the effect of radiation

5FU – Administered through an IV infusion over several days (or tablets – capecitabine, taken twice a day on days of radiotherapy). It blocks cancer cell growth by interfering with DNA synthesis
Cisplatin – Administered through an IV infusion, typically in combination with other chemotherapy drugs like 5FU. Cisplatin works by forming cross-links in DNA, which prevents cancer cells from dividing and growing. It is often used in combination with radiation therapy to enhance the effectiveness of treatment.
Radiation Therapy (in CRT) is delivered externally to target the tumour and nearby tissues. It is typically given in daily sessions (Monday to Friday) over 5-6 weeks. It focuses on the anal tumour and regional lymph nodes to prevent recurrence. The key benefits of radiation therapy are that it preserves the anal sphincter, avoiding the need for major surgery and has proven high cure rates in localised anal cancer

Radiotherapy

There are two types of radiotherapy commonly given to anal cancer patients:

IMRT (Intensity-Modulated Radiation Therapy) is an advanced type of radiation therapy used to treat cancer. It delivers very precise radiation doses to a malignant tumour or specific areas within the tumour. A higher radiation dose is focused on a smaller area, minimising harm to surrounding (healthy) tissues
VMAT (Volumetric Modulated Arc Therapy): This is a newer form of IMRT that delivers the radiation dose continuously as the treatment machine rotates around the patient. VMAT can deliver the dose to the entire tumour in single or multiple arcs of the machine around the patient. This technique allows for precise targeting of the tumour while sparing healthy tissue.

Advanced radiotherapy is a term used to describe the most cutting-edge machines in the world to deliver radiotherapy to cancer patients. Cromwell Hospital, where Dr Andy Gaya is based, has a range of leading technologies in radiotherapy such as Gamma Knife Icon, Varian Edge, Cyberknife and MRIdian MR Linac

In summary

CRT achieves complete response rates of ~90% for localised anal cancer and 5-year survival rates of up to 80% for Stages I-III. It also usually preserves anal sphincter function, unless the sphincters are already damaged, avoiding the need for permanent colostomy in most cases. CRT is supported by decades of research and remains the cornerstone of treatment, with refinements in radiation delivery (e.g. IMRT) further improving outcomes and reducing toxicity.

Summary of evidence supporting Chemoradiotherapy (CRT) in anal cancer

Nigro Protocol (1974) demonstrated that combining 5-FU, mitomycin C, and radiation could achieve high rates of tumour regression and sphincter preservation, making it the foundation of treatment for anal cancer and a viable non-surgical option for squamous cell carcinoma.

ACT I Trial (1996, UK) was one of the earliest landmark UK trials comparing CRT versus radiation alone. CRT significantly improved local control and disease-free survival, making it the gold standard for localised anal squamous cell carcinoma

ACT II Trial (2008, UK) investigated whether cisplatin-based (another chemo drug) CRT could replace mitomycin C + 5-FU and whether maintenance chemotherapy improves outcomes. Mitomycin C + 5-FU (or capecitabine) remained the preferred regimen due to simplicity and efficacy

RTOG 98-11 Trial (2012, USA) also found Mitomycin C-based CRT gave superior outcomes

RTOG 0529 Trial (2012, USA) evaluated intensity-modulated radiation therapy (IMRT) combined with standard chemotherapy (5-FU + mitomycin C). IMRT significantly reduced acute grade 2+ gastrointestinal (21%) and dermatologic (22%) toxicity compared to historical data from older techniques and is now recommended as the preferred radiation technique for anal cancer when available

What are the most common side effects of CRT and best management strategies?

Category	Common Side Effects	Management Strategies
Skin	Redness, peeling, or sores in the treated area.	Use prescribed creams; avoid tight clothing. Use baby wipes down below or warm water
Digestive	Diarrhoea, rectal discomfort.	Hydration, anti-diarrheal medications. Local anaesthetic creams
Systemic	Fatigue, nausea.	Rest, anti-nausea medications.
Long-term Effects	Anal stricture or incontinence (rare)	Regular follow-ups and physical therapy if needed.

Why are some anal cancer patients given a colostomy bag?

Surgery is an option for some anal cancer patients if they recur after chemoradiotherapy. Abdominoperineal Resection (APR) removes the anus and rectum, and creates an ‘exit’ or ‘stoma’ on the abdomen of the patient (directly connecting the colon to the torso). The person will have a permanent colostomy bag (a bag which collects waste). This surgery is rarely needed because CRT is highly effective in early and moderate stages, it is usually only recommended if cancer persists or recurs after CRT.

Sometimes a temporary stoma is recommended if the anal tumour is very bulky and might block the bowel, to protect against bowel obstruction during radiotherapy.

Stage IV (advanced) Anal Cancer treatments

Patients with advanced anal cancer may be offered one or more of the following treatment options, based on the individual’s type of cancer, stage and how far it is spread in the body (and where it has spread to). Combining treatments can give a patient the best chance of fighting cancer.

By working with a world leading Consultant Oncologist like Dr Gaya, a patient will be given a personalised cancer treatment plan, which takes into consideration the patient’s overall health. Dr Andy Gaya also has his finger on the pulse of the newest cancer drugs and can also provide information about Clinical Trials and how to access drugs that are being researched.

Systemic Therapy

For advanced anal cancer (stage IV or recurrent cancer that has spread to distant organs), systemic therapy plays a key role. Systemic therapy targets cancer cells wherever they may be in the body, not just in the primary tumour location. Systemic therapy refers to treatment that works throughout the body to control cancer, shrink tumours and relieve symptoms. It’s used for cancers that have spread (metastasized) to other parts of the body. The goals of systemic therapy are to:

Slow the growth or spread of cancer
Prolong survival
Maintain the best possible quality of life.
Shrink tumours to relieve symptoms (palliative care)

In advanced anal cancer, oncologists typically use a combination of chemotherapy drugs and immunotherapy where appropriate.

Chemotherapy

Chemotherapy uses combinations of drugs to kill cancer cells or slow/stop their growth. It is often the first-choice treatment for advanced anal cancer. This table shows some typical chemotherapy regimens and the goal of treatment.

Common Chemotherapy Regimens	Drugs Used	Purpose
Cisplatin + 5-Fluorouracil (5-FU)	Cisplatin and 5-FU	Shrinks tumours and slows spread. A treatment option for advanced cases.
Carboplatin + Paclitaxel	Carboplatin and Paclitaxel	Standard first line chemotherapy option for advanced cancer with fewer side effects; effective in many patients and often preferred in advanced anal cancer based on better tolerability and longer survival (InterAACT Trial).
FOLFOX	5-FU, leucovorin, oxaliplatin	Used in some cases as an additional option if the cancer progresses.

Chemotherapy regimens remain the backbone for first-line treatment. Most people will experience side effects from chemotherapy like nausea, vomiting, hair loss, fatigue, risk of infections and nerve damage. These can be managed by taking anti-nausea and pain management drugs, as well as plenty of rest and a healthy diet.

Summary of Key Clinical Trials Supporting Systemic Therapy for Advanced Anal Cancer

InterAACT Trial (2020) – Investigated first-line treatments for advanced anal cancer (Stage IV). It found cisplatin + 5-FU and carboplatin + paclitaxel effective, with carboplatin + paclitaxel showing fewer side effects and better tolerability. Highlights the importance of systemic therapy for metastatic disease.

ANAL Cancer Immunotherapy Studies – Emerging trials are evaluating the role of immune checkpoint inhibitors (ICIs) such as pembrolizumab and nivolumab in advanced anal cancer. Early studies show promise for ICIs in PD-L1-positive tumours or mismatch repair deficiency

SABR

Stereotactic Ablative Body Radiotherapy (SABR), also known as Stereotactic Body Radiotherapy (SBRT), is a highly precise form of radiation therapy used to treat certain types of cancer, including anal cancer. SABR delivers high doses of radiation to a small, well-defined tumour area while minimising damage to surrounding healthy tissue.

In the context of anal cancer, SABR can be used to target tumours with great accuracy, making it an effective option for treating localised tumours, metastases or pelvic recurrence. The treatment involves multiple small, focused beams of radiation directed from different angles and is typically used when surgery is not an option (or when the tumour is located in a challenging area). It can also be used to re-treat areas that have previously received radiation therapy.

Immunotherapy

The newest cancer drugs use the body’s own immune system to attack cancer cells. Immunotherapy is effective for advanced or recurrent anal cancers, particularly cancers that express PD-L1 or have genetic changes like high microsatellite instability (MSI-H). Clinical trials are evaluating the role of immunotherapy in combination with CRT.

Drug	Type	When Used
Pembrolizumab	PD-1 immune checkpoint inhibitor	For cancers with PD-L1 positivity or MSI-H, it helps the immune system attack the cancer cells
Nivolumab	Carboplatin and Paclitaxel	Standard first line chemotherapy option for advanced cancer with fewer side effects; effective in many patients and often preferred in advanced anal cancer based on better tolerability and longer survival (InterAACT Trial).
FOLFOX	5-FU, leucovorin, oxaliplatin	Used in some cases as an additional option if the cancer progresses.

Immunotherapy can have side effects such as fatigue, rash, diarrhoea, rare inflammation of lungs, liver, or other organs. Early communication with the patient’s care team is essential and steroids can be prescribed if side effects are severe.

Summary of Key Clinical Trials Supporting Immunotherapy for Advanced Anal Cancer

KEYNOTE-158 / KEYNOTE-028 Trials (2018, 2020) – both studies found Pembrolizumab is an effective option for a subset of patients with advanced anal cancer, especially those with PD-L1-positive tumours. For patients with recurrent/metastatic anal cancer (who have exhausted chemotherapy options) it can improve survival (for years in some cases)

CHECKMATE 358 – Evaluated Nivolumab, another PD-1 inhibitor, in patients with advanced or refractory anal cancer. It demonstrated significant responses, particularly in patients with immune-sensitive tumours. The treatment was well-tolerated, with only mild side effects

Clinical trials continue to improve outcomes, offering new hope for advanced anal cancer patients. Dr Gaya will be able to discuss clinical trial opportunities if you have advanced anal cancer which cannot be cured with current treatment protocols.

Will a stage 4 anal cancer patient be offered CRT?

Chemoradiotherapy is sometimes still used for stage 4 anal cancer. The aim of treatment is to deliver “local control” to deal with the pelvis disease, usually alongside SABR and/or immunotherapy.

Living with Anal Cancer

Incurable anal cancer is quite rare. For these patients treatment is focused on symptom management, so a person can live comfortably as possible. Patients of Dr Gaya will benefit from a team approach – with oncologists, nurses and support staff – working together to provide holisctic care. This is referred to as ‘palliative care’ and typically involved treatments like local radiation to target individual tumours, supportive therapies, emotional support and pain management.

Treatments for anal cancer are advancing everyday: emerging therapies – like new immunotherapies and targeted treatments – may be available. Dr Gaya will be able to advise on the latest clinical trials patients may be suitable for, based on their anal cancer diagnosis and/or the genetic profile of their tumour.

A holistic approach

Knowing the genetic profile of a tumour and having a personalised treatment plan can be hugely empowering. Dr Gaya will compliment this with guidance on other therapies which research has shown could help your overall quality of life and survival. Dr Gaya can advise on everything from exercise, probiotics to vitamins to supplements to wholefoods from his wealth of knowledge in the field.

A patient’s overall health is a strong indicator of how well they will respond to cancer treatment, so it is important to implement a healthy diet, lifestyle changes and activity or exercise regime. Dr Gaya advises all his anal cancer patients to stop smoking immediately and maintain a healthy diet and weight while undergoing treatment. Smoking can be detrimental during radiotherapy as it reduces blood oxygen levels.

Improving outcomes

When it comes to a cancer diagnosis, it’s important to have a big team of people around. From having family and friends rallying around the patient at home to having an excellent Clinical Oncologist driving cancer treatment in the hospital.

When a person with anal Cancer is treated by Dr Gaya, their case will be discussed at a multidisciplinary team (MDT) meeting, which is made up of a panel of medical specialists. This includes other cancer doctors like surgeons and interventional radiologists and oncology nurses, as well as tapping into the unique knowledge of broader experts like physios, occupational therapists, psychiatrists, mental health specialists, dieticians, nutritionists and complementary therapists, as needed.

Having a range of experts input into cancer patient’s care is an optimal approach to treatment. Experts are based at Dr Gaya’s hospitals in London or, if more convenient, his team can recommend healthcare services local to the patient.

Follow up care

All anal cancer patients will have regular monitoring. Follow up visits will be frequent for the first two years and ‘surveillance’ every few years may continue with Dr Gaya or other healthcare professionals. Follow up care will likely involve physical exams, colonoscopies and imaging tests to check for recurrence.

Cancer and Lifestyle Changes

Patient Information