Anal Canal Cancer

Risk Factors

• Cigarette smoking
• HPV infection with high risk genotypes
• HIV seropositivity and low CD 4 count
• Immune suppresion following transplant
• Cervical dysplasia, cervical cancer, or genital warts
• Anoreceptive intercourse

Clinical Presentation

• Pain or sensation of mass- 30% of the patients
• Rectal bleeding- 45% of the patients
• No symptoms- 20% of all the cases
• Paget’s disease

Diagnostic Workup

• Physical exam- rectal and nodes
• Biopsy- for differentiating between squamous cell (anal ca) and adenocarcinoma (rectal ca)
• CT scan- for metastatic disease
• EUS- for identifying sphincter involvement as well as perianal lymph nodes
• PET scan- for precisely determining metastatic disease and inguinal nodes

Treatment

The main objective of the anal cancer treatment in Kolkata is to have a cure with locoregional control, associated with the preservation of anal sphincter function while maintaining the quality of life.

Squamous cell Carcinoma

Majority of the anal canal tumors (85%) is related to SCC. Today, a combination therapy, involving chemotherapy and radiotherapy with a radiation providing a complete reduction in 80–90% of the patients, has become the standard treatment for non-metastatic squamous cell carcinoma. Approximately, in 15% of the patients the disease will persist initially and in another 15%, late locoregional recurrence may develop.

Abdominoperineal resection, as well as permanent colostomy surgeries in SCC is recommended for patients with recurrent or residual disease after a complete chemo radiotherapy. Surgical anal cancer treatment, after recurrence, allows for a local control in about 60% of the cases, along with a 5-year-survival rate of 30–60%.

Adenocarcinoma

Adenocarcinoma associated with the anal canal are tumors (15% of the cases) and are believed to develop from the ducts or the intramuscular anal glands, as well as the long-standing fistulas. The neoplasms affect the older age groups and does not have any sexual predominance. Most of the lesions are slow-growing, locally aggressive, and seldom metastasize. The plenty of mucin produced by these tumors explain their tendency to dissect soft tissue planes. A local surgical removal may be performed for well-differentiated carcinomas, which have not invaded the sphincter mechanism. Otherwise, the APR is indicated.

Melanoma

The third most common site where melanoma occurs is the anal canal. The average age of occurrence is in the fifties, with the females being affected more frequently than the males. Surgery is the only hope for cure, though significant differences in survival between people treated with local surgical removal and patients with APR have not been shown. However, APR possibly provides better local control of this disease.

Treatment of Locally Recurrent and Metastatic Disease with Chemotherapy: Different regimens of salvage chemotherapy may be used for metastatic anal carcinoma in place of the most common regimens presently being employed.