Anal cancer

Most anal cancers are squamous cell carcinomas. The report should distinguish the anal canal from the surrounding perianal skin and confirm whether the lesion is invasive. Adenocarcinoma and melanoma in this area follow different pathways, so a treatment plan based only on the phrase ‘anal mass’ is incomplete.

Bleeding, pain, a lump, itching or a change in bowel control can resemble hemorrhoids or other benign problems. Persistent symptoms need examination and, when indicated, biopsy. High-grade squamous intraepithelial lesions are precancerous changes, not the same diagnosis as invasive cancer.

Persistent high-risk HPV infection is linked to most anal squamous cancers. HPV is common and can persist for years; a cancer diagnosis does not establish when the infection began. Smoking and impaired immunity, including HIV or transplant-related immunosuppression, also affect risk.

Tell the team about HIV medicines, immune-suppressing treatment and prior HPV-related disease. These details help coordinate safe cancer care and appropriate follow-up. HPV vaccination is preventive; it does not replace treatment for an established cancer. Questions about sexual health deserve the same clear, respectful discussion as other treatment concerns.

Assessment usually includes examination of the anus and groins, anoscopy with biopsy, pelvic imaging and scans for distant disease. Pelvic MRI helps map local extent; PET/CT may add information about involved nodes and radiation planning. Suspicious groin nodes are important because they can be regional disease rather than distant metastases.

AJCC’s current anal cancer protocol is Version 9. Tumor size, invasion into neighboring organs, regional nodes and distant spread determine the stage. Stage and the feasibility of curative local treatment should be discussed together; the word ‘advanced’ alone does not tell you whether treatment still aims to cure.

For most localized anal squamous cancers requiring definitive treatment, radiation with concurrent chemotherapy is the central organ-preserving approach. Mitomycin with fluorouracil is a common combination; capecitabine can substitute for fluorouracil in appropriate patients. Modern intensity-modulated radiation helps shape treatment around normal tissues.

Selected very small superficial or favorable perianal lesions may be managed with local excision after careful review of margins and sphincter function. This exception should not be generalized to all small anal canal cancers. Plan skin care, pain control, bowel support and nutrition early to reduce avoidable treatment interruptions.

The treated area can remain inflamed or thickened while the cancer is regressing. Early review checks healing and whether the lesion is improving; it is not always the final response assessment. In ACT II, some patients who had not achieved a complete response early did so by 26 weeks from the start of chemoradiation. That study interval is measured from treatment start, not from its last day.

A shrinking or stable residual abnormality without evidence of progression may be followed closely over several months according to the team’s plan. An enlarging lesion, new disease or worsening concerning symptoms needs earlier assessment. Waiting for recovery does not mean ignoring progression, and a persistent lump should not automatically trigger immediate radical surgery without evaluation.

Biopsy-confirmed persistent or locally recurrent cancer after adequate chemoradiation assessment can lead to salvage surgery. Abdominoperineal resection removes the anus and rectum and usually requires a permanent colostomy. Restaging first establishes whether surgery can address the disease and what reconstruction may be needed.

Some patients need diversion of stool to manage severe symptoms, obstruction or a fistula even when the cancer plan is different. A temporary or permanent stoma is therefore not, by itself, evidence that treatment has failed. Discuss wound healing, function and practical stoma support before an operation.

For adults with inoperable locally recurrent or metastatic squamous cell carcinoma of the anal canal, the US label includes retifanlimab with carboplatin and paclitaxel as first-line treatment. Retifanlimab alone is also approved for locally recurrent or metastatic disease progressing on, or intolerant of, platinum-based chemotherapy. These indications do not require a positive PD-L1 test.

This approval does not make retifanlimab a routine addition to curative chemoradiation for every newly diagnosed patient. Prior immunotherapy, neuropathy, marrow function, autoimmune disease and treatment goals affect subsequent choices. Immune treatment can inflame organs including bowel, lung, liver and endocrine glands; new symptoms should be reported promptly.

Skin soreness, painful bowel movements, diarrhea, fatigue and urinary discomfort can occur during pelvic treatment. Ask for a clear plan for symptom control and whom to contact if pain prevents eating or drinking, fever develops, or bleeding becomes substantial. Do not stop treatment on your own; the team can assess whether a change or pause is needed.

Later effects can include bowel urgency or leakage, sexual difficulties, vaginal narrowing, erectile problems and fertility changes. Discuss fertility preservation before treatment if relevant, and request pelvic-floor or sexual-health support afterward. Follow-up examines the treated area and groin nodes, with imaging tailored to risk and findings; it also addresses function, not only recurrence.

• Pathology, exact anal canal or perianal site, pelvic MRI and staging scans.
• Full radiation plan and dose record if already treated, chemotherapy dates and response assessments.
• Current bowel and urinary symptoms, medication list, immune-health history and personal recovery priorities.