Prognostic factors in anal squamous carcinoma: a multivariate analysis of clinical, pathological and flow cytometric parameters in 235 cases

Prognostic value of fluorodeoxyglucose positron emission tomography/computed tomography and inguinal sentinel lymph node biopsy in patients with anal cancer

AIM

The aim of this study was to assess the value of positron emission tomography (PET)/CT and sentinel lymph node (SLN) biopsy in staging inguinal lymph nodes in anal cancer patients and to determine if the results of the two methods could be of prognostic value.

METHOD

Sixty-three patients with anal cancer and clinically negative inguinal lymph nodes underwent lymphoscintigraphy and inguinal SLN biopsy and/or fluorodeoxyglucose (FDG) PET/CT scan. All patients were treated with radiotherapy combined with 5-fluorouracil and mitomycin-C.

RESULTS

Overall (OS) and disease-free survival (DFS) were 43 months (range 5-211) and 43 months (range 4-142) respectively. PET/CT examination showed high FDG uptake in the inguinal lymph nodes in 25% of patients. Thirty-five patients with inguinal uptake at lymphoscintigraphy underwent inguinal SLN biopsy and metastatic nodes were found in 31.4%. There was no statistical difference in OS (55 vs 41 months; P = 0.652) and DFS (48 vs 38 months; P = 0.992) between the group which showed inguinal uptake on PET/CT and the group which did not, while a positive inguinal SLN was associated with a worse OS (28 vs 59 months; P = 0.028) and DFS (56 vs 21 months; P = 0.046). When the two examinations were compared PET/CT showed a sensitivity, specificity, positive predictive value and negative predictive value of 22%, 82%, 33% and 73% respectively.

CONCLUSION

The technique of SLN biopsy had a better diagnostic accuracy than total body FDG-PET/CT for the staging of inguinal lymph nodes in anal cancer patients; moreover it was a stronger predictor of OS and DFS than PET/CT.

Mucoepidermoid carcinoma of the anal canal: A case report and review of the literature

Mucoepidermoid carcinoma of the anal canal is a rare tumor. We herein report the case of a 74-year-old male patient with a high-grade mucoepidermoid carcinoma of the anal canal who was treated by local surgical resection and subsequent irradiation. However, the patient succumbed to liver and lung metastases 2 years after the procedure. The characteristic findings of mucoepidermoid carcinoma of the anus remain unclear to date due to rarity of this tumor. Since 1954, when this type of tumor was first described, only 58 cases of patients diagnosed with mucoepidermoid carcinoma of the anus have been reported to date. In this context, a review of the existing English literature on this rare tumor was also performed.

Background and Current Treatment of Squamous Cell Carcinoma of the Anus

In this review, a summary of our current understanding of squamous cell carcinoma of the anus (SCCA) and the advances in our knowledge of SCCA regarding screening, prevention, the role of the immune system, current treatment and the potential for novel targets are discussed. The present standard of care in terms of treatment is 5-fluorouracil (5-FU) and mitomycin C (MMC) concurrently with radiation, which results in a high level of disease control for small early cancers. Preservation of the anal sphincter is achieved in the majority, although anorectal function is often impaired. Although evidence from prospective studies to support a change in the treatment strategy is lacking, patients with HPV-negative SCCA appear to be less responsive to chemoradiation (CRT) and relapse more frequently. In contrast, HPV-positive tumours usually fare better, but oncological outcomes are modified by smoking and immune incompetence. There is current interest in escalating the radiotherapy dose for larger, more advanced tumours, and de-escalating treatment for HPV-positive tumours. The use of novel immunological treatments to target the underlying different molecular pathways of HPV-positive cancers is exciting.

Basaloid Squamous Cell Carcinoma of the Anus Revisited

Basaloid squamous cell carcinoma (SCC) of the anus, previously called cloacogenic carcinoma, is a subtype of SCC. There are very few data on the morphologic variation within basaloid SCC of the anus, which may contribute to misdiagnosis. We retrospectively evaluated cases originally diagnosed as basaloid SCC for histologic characterization. We retrieved and reviewed cases of basaloid SCC from 1994 to 2013. Ten (27%) cases were reclassified after review, including basal cell carcinoma (n=6), melanoma (n=2), and neuroendocrine carcinoma (n=2). The final group of basaloid SCC (n=27) showed a female predominance (median age=60 y; range, 42 to 92 y). Morphologically, basaloid SCC could be categorized into 4 groups: transitional carcinoma like (n=10), basaloid with peripheral palisade (n=13), adenoid cystic carcinoma like (n=3), and mucinous microcystic (n=1). In 19 cases the histologic patterns were pure and were mixed in the remainder. CK5/6, p16, and high-risk HPV were positive in all cases (n=27). SOX2 was positive in 18/22 cases. Clinical follow-up was available on 60% of cases; 9 patients (53%) developed local recurrence or metastasis, and 5 (29%) died of disease. Basaloid SCC of the anus is characterized by 4 major histologic patterns and is consistently HPV driven.

New approach to anal cancer: Individualized therapy based on sentinel lymph node biopsy

Oncological treatment is currently directed toward a tailored therapy concept. Squamous cell carcinoma of the anal canal could be considered a suitable platform to test new therapeutic strategies to minimize treatment morbidity. Standard of care for patients with anal canal cancer consists of a combination of radiotherapy and chemotherapy. This treatment has led to a high rate of local control and a 60% cure rate with preservation of the anal sphincter, thus replacing surgical abdominoperineal resection. Lymph node metastases represent a critical independent prognostic factor for local recurrence and survival. Mesorectal and iliac lymph nodes are usually included in the radiation field, whereas the inclusion of inguinal regions still remains controversial because of the subsequent adverse side effects. Sentinel lymph node biopsies could clearly identify inguinal node-positive patients eligible for therapeutic groin irradiation. A sentinel lymph node navigation procedure is reported here to be a feasible and effective method for establishing the true inguinal node status in patients suffering from anal canal cancer. Based on the results of sentinel node biopsies, a selective approach could be proposed where node-positive patients could be selected for inguinal node irradiation while node-negative patients could take advantage of inguinal sparing irradiation, thus avoiding toxic side effects.

To PET or not to PET? That is the question. Staging in anal cancer

BACKGROUND

Anal cancer is a rare tumour accounting for ∼2% of all colorectal cancers between 1997 and 2000 in the UK. Staging is still dominated by DRE (digital rectal examination), computed tomography (CT) and magnetic resonance imaging (MRI) imaging. The role of PET as a definitive modality is still emerging and there are relatively few adequate studies in the literature.

METHODS

We looked at patients treated radically for anal cancer at Mount Vernon Cancer Centre (UK) between 2009 and 2010. Eighty-eight patients underwent treatment according to data-based coding records of which 46 had positron emission tomography (PET)/CT scans. Notes were unavailable for three patients. We compared staging following conventional modalities (DRE, MRI and CT) and PET/CT scans for these 43 patients.

RESULTS

In 18 patients, the PET/CT stage differed from MRI. PET/CT altered the stage in 42% of patients but changes in subsequent management were not implemented.

CONCLUSIONS

Our data show that PET/CT does alter staging in a significant number of cases although it did not lead to change in management under the current guidelines. Furthermore, there is agreement that PET/CT shows greater sensitivity for detection of lymph nodes and our study has demonstrated a distinct trend towards upstaging of anal cancer with PET/CT.

Metastatic squamous cell carcinoma of the anus: time for a shift in the treatment paradigm?

Anal cancers are rare tumours; however, the incidence is increasing in both men and women. Changing trends in sexual behaviour, smoking, and infection with the human papillomavirus are thought to be responsible for the increase. Patients with metastatic disease have a poor prognosis, with 5-year median overall survival rates of 10% in men and 20% in women. The standard systemic treatment of metastatic disease remains cisplatin and 5-fluorouracil, and aside from several non-randomised small phase II trials there has been no real progress over the past two decades. Based on the efficacy of cetuximab in squamous cell carcinomas from other primary sites, there appears to be clinical rationale for evaluation of anti-epidermal growth factor inhibitors in anal squamous cell carcinoma. In order to facilitate research and implement more effective treatment strategies international collaboration in clinical trials incorporating tissue collection for biomarkers is essential.

An update on tumors of the anal canal

CONTEXT

The anal canal possesses complex anatomy and histology and gives rise to a variety of tumor types. Challenging issues remain with regard to both the pathologic diagnosis and the clinical management of these tumors.

OBJECTIVES

To provide an updated overview of the histogenesis, clinical and pathologic characteristics, diagnostic terminology, and relevant clinical management of the various types of anal canal tumors.

DATA SOURCES

Recent literature on clinical and pathologic characteristics of anal canal tumors.

CONCLUSIONS

Although most anal canal tumors are of squamous lineage, a complex variety of other tumors also occurs. Recognition of such diverse tumor entities will allow accurate pathologic diagnosis and most optimal clinical management.

Outcomes and prognostic factors for squamous-cell carcinoma of the anal canal: analysis of patients from the National Cancer Data Base

PURPOSE

The objective of this study was to assess survival and prognostic factors for anal carcinoma in the population.

METHODS

Patients with squamous-cell carcinoma of the anal canal were identified from the National Cancer Data Base (1985-2000). Univariate and multivariable methods were used to assess factors associated with survival. Concordance was calculated to assess agreement between American Joint Committee on Cancer stage and actual outcome.

RESULTS

Nineteen thousand one hundred ninety-nine patients with anal carcinoma were identified (Stage I, 25.3 percent; Stage II, 51.8 percent; Stage III, 17.1 percent; Stage IV, 5.7 percent). Overall five-year survival was 58.0 percent. The American Joint Committee on Cancer (6th edition) staging system provided good survival discrimination by stage: I, 69.5 percent; II, 59.0 percent; III, 40.6 percent; and IV, 18.7 percent (concordance index, 0.663). On multivariable analysis, patients with anal carcinoma had a higher risk of death if they were male, >or=65 years old, black, living in lower median incomes areas, and had more advanced T stage tumors, nodal or distant metastases, or poorly differentiated cancers (P < 0.0001). There was not a significant difference in survival by hospital type or year of diagnosis.

CONCLUSION

Although tumor characteristics and staging affect prognosis, patient factors, such as gender, race, and socioeconomic status, are also important prognostic factors for squamous-cell carcinoma of the anal canal.

Diagnostic problems in anal pathology

Anal squamous cell carcinoma and its precursor lesions are increasing in incidence in the United States and Europe. This trend predates human immunodeficiency virus/acquired immune deficiency syndrome and has been associated with persistent high-risk human papilloma virus (HPV) genotype infection, previous lower genital tract dysplasia/carcinoma, high frequency anoreceptive intercourse, heavy cigarette smoking, immunosuppression in solid organ transplant and immune disorders, and human immunodeficiency virus seropositivity. Screening protocols for at-risk patients are under active investigation and pathologists are often asked to assess anal canal and perianal biopsies for the presence of dysplasia and/or invasive carcinoma. Because underdiagnosis and overdiagnosis of anal cancer and precancer may lead to inappropriate treatment, it is important for the pathologist to be aware of current screening strategies, specific risk lesions, and the role of pathology in initial diagnosis and evaluation of anal biopsy and/or resection specimens. Standardized histologic criteria and uniform terminology should be used for reporting all anal canal and perianal squamous intraepithelial lesions. HPV subtyping, anal cytology, and recently identified biomarkers, such as p16 and Becton Dickinson ProEx C may provide additional information in problematic cases, but it is important to be aware of the limitations of these assays. HPV has been linked to all the major histologic subtypes of anal carcinoma (eg, basaloid, cloacogenic, transitional, etc.) and this association is strongest for anal canal lesions. With the possible exception of the microcystic pattern, histologic subtype does not seem to predict prognosis; and anal squamous cell carcinomas should be classified as either keratinizing or nonkeratinizing. Poorly differentiated squamous cell carcinomas have a worse prognosis and should be distinguished from poorly differentiated adenocarcinoma, melanoma, and neuroendocrine tumors. Very well differentiated squamous cell carcinoma with pushing margins (so-called giant condyloma of Buschke and Lowenstein) should be classified as verrucous carcinoma; this tumor shows aggressive local infiltration but does not metastasize. As all anal condylomata may harbor foci of high-grade dysplasia or invasive carcinoma, careful sectioning and complete histologic examination is required.

Justification for staging of epidermoid anal carcinoma after salvage surgery: a pathological guideline

The currently accepted first line treatment for epidermoid anal cancer is chemoradiotherapy (CRT). Tumour size and adjacent organ involvement are the key in the pretreatment assessment for T1-T4 tumours respectively. Residual or recurrent disease following initial CRT, is best treated by salvage anorectal excision. Pathological staging systems of resections were historically validated when surgery was the primary treatment and are therefore in need of revision. We propose a new pathological staging system for salvage anorectal excision specimens to allow improved prognostic guidelines postoperatively.

Bilan préthérapeutique initial du carcinome épidermoïde invasif de l’anus

Anal epidermoid carcinoma is a rare malignant tumor, comprising less than 5% of all carcinomas of the colon, rectum, and anus. The primary therapy now includes radiotherapy, often in combination with chemotherapy. Radical surgery is now rarely indicated. Therapeutic indications are based on locoregional staging, the presence of visceral metastases and an evaluation of the medical history. Anorectal endosonography is helpful in evaluating locoregional extension. In addition, magnetic resonance imaging, positron emission tomography scanning and inguinal sentinel lymph node procedure should play a role in a more selective approach in patients with anal carcinoma.

Local tumor control and toxicity in HIV-associated anal carcinoma treated with radiotherapy in the era of antiretroviral therapy

PURPOSE

To investigate the outcome of HIV-seropositive patients under highly active antiretroviral treatment (HAART) with anal cancer treated with radiotherapy (RT) alone or in combination with standard chemotherapy (CT).

PATIENTS AND METHODS

Clinical outcome of 81 HIV-seronegative patients (1988-2003) and 10 consecutive HIV-seropositive patients under HAART (1997-2003) that were treated with 3-D conformal RT of 59.4 Gy and standard 5-fluorouracil and mitomycin-C were retrospectively analysed. 10 TNM-stage and age matched HIV-seronegative patients (1992-2003) were compared with the 10 HIV-seropositive patients. Pattern of care, local disease control (LC), overall survival (OS), cancer-specific survival (CSS), and toxicity were assessed.

RESULTS

RT with or without CT resulted in complete response in 100% of HIV-seropositive patients. LC was impaired compared to matched HIV-seronegative patients after a median follow-up of 44 months (p = 0.03). OS at 5 years was 70% in HIV-seropositive patients receiving HAART and 69% in the matched controls. Colostomy-free survival was 70% (HIV+) and 100% (matched HIV-) and 78% (all HIV-). No HIV-seropositive patient received an interstitial brachytherapy boost compared to 42% of all HIV-seronegative patients and adherence to chemotherapy seemed to be difficult in HIV-seropositive patients. Acute hematological toxicity reaching 50% was high in HIV-seropositive patients receiving MMC compared with 0% in matched HIV-seronegative patients (p = 0.05) or 12% in all HIV-seronegative patients. The rate of long-term side effects was low in HIV-seropositive patients.

CONCLUSION

Despite high response rates to organ preserving treatment with RT with or without CT, local tumor failure seems to be high in HIV-positive patients receiving HAART. HIV-seropositive patients are subject to treatment bias, being less likely treated with interstitial brachytherapy boost probably due to HIV-infection, and they are at risk to receive less chemotherapy.

Epidermoid anal cancer: a review of a population-based series of 308 consecutive patients treated according to prospective protocols

PURPOSE

The primary therapy in epidermoid anal cancer is radiotherapy, generally with chemotherapy. The use of neoadjuvant chemotherapy has been infrequently reported in the literature. This study presents results from a large population-based series and provides comparisons between different treatments.

METHODS AND MATERIALS

Between 1985 and 2000, 308 patients with invasive epidermoid anal cancer were diagnosed in the Stockholm Health Care Region. Treatment was given according to defined protocols. External beam radiotherapy alone or with concomitant bleomycin and neoadjuvant chemotherapy followed by radiotherapy alone were the primary treatments. Radical surgery was reserved for poor responders or recurrences. Data were reviewed with regard to treatment, outcome, and prognostic factors.

RESULTS

Among the 276 patients (90%) treated with curative intent, 264 (96%) received treatment in accordance with the protocols. The overall 5-year survival rate was 68%. Among the 142 patients with locally advanced tumors (T > or =4 cm or N+), patients treated with neoadjuvant platinum-based chemotherapy (n = 91) had significantly better complete response rates compared with patients treated with radiotherapy with or without bleomycin (n = 51) (92% vs. 76%, p < 0.01). A significantly increased overall 5-year survival rate was also found among patients receiving neoadjuvant therapy (63% vs. 44%, p < 0.05).

CONCLUSION

Structured treatment protocols result in favorable outcome on a population level. The results further suggest a significant therapeutic gain from including neoadjuvant chemotherapy in the treatment of locally advanced anal cancer.

Transrectal ultrasound color Doppler in the evaluation of recurrence of anal canal cancer

OBJECTIVE

aim was to obtain elements for a differential diagnosis between post-radiation fibrosis and residual tumor or local relapse in anal canal cancer through detection of presence/absence of intralesional blood flow. Transrectal ultrasound and color Doppler were compared.

METHODS

43 patients underwent transrectal ultrasound sonography and color Doppler before and after therapy to assess intralesional blood flow and flow pattern (spotty and linear signals). All diagnostic imaging results were compared to histological analysis. Specificity was submitted to statistical analysis using McNemar test.

RESULTS

before therapy 34 lesions (79%) showed color signal; no signal in 9 (21%), which were excluded from our analysis. Eighteen of the 34 patients considered, presented complete response to therapy, 14 partial response and two no response. After therapy, signal disappeared in 17 patients (94%); one false-positive (6%) presented spotty signals; 16 of 34 patients presented changed color signal. Color Doppler showed higher specificity than grey scale transrectal ultrasound in the differentiation of fibrosis from tumor. Response was confirmed by histological examination, considered gold standard. McNemar test demonstrated the significance of color Doppler (P < 0.0001).

CONCLUSION

color Doppler considerably increases transrectal ultrasound specificity in differentiating tumor relapse from fibrosis in anal canal cancer.

Pathological staging of epidermoid anal carcinoma for the new era

Chemoradiotherapy is the standard treatment for most patients with epidermoid anal cancer. Pre-treatment staging is based on size for T1-T3 lesions and clinical and radiological assessment of adjacent organ invasion for T4 lesions. For patients with residual or recurrent carcinoma, anorectal excision offers the best chance of oncological salvage. Pathological staging systems for anorectal excision specimens were validated at the time when surgical treatment was first line therapy. A validated staging system is necessary for salvage surgical excision specimens following an attempt to cure by radiotherapy and chemotherapy for the purpose of prognosis and further treatment planning.

Prognostic factors in anal carcinoma

The pathologist's role in the evaluation of patients with anal squamous carcinoma is now largely restricted to establishing the diagnosis on small biopsies. Staging is performed by imaging techniques and grading is uncertain as the biopsy may not be representative of the whole tumour. Histological subtyping is unreliable and has not been proven to be of prognostic significance. A considerable effort resulting in nearly 50 reports on cytogenetic, flow cytometric, immunohistochemical and other investigations has given new insight into pathogenesis but little guidance with regard to the individual prognosis or choice of treatment. It is concluded that future research should concentrate on larger, probably multicentre series using standardised methods and criteria for evaluation.

SQUAMOUS CELL CARCINOMA OF THE ANAL CANAL AND ANAL MARGIN

Squamous cell carcinomas of the anal canal and margin are relatively uncommon neoplasms of the distal gastrointestinal tract and surrounding skin. The major risk factors for tumor development have been defined through various epidemiologic studies. Randomized, phase III trials have defined the standard of care for anal cancer tumors to be a combined modality approach of radiation therapy and chemotherapy. This nonsurgical, organ-sparing regimen results in good anal sphincter function in the majority of patients, and treatment efficacy is favorable when compared with historic surgical series. Anal margin tumors are staged and treated as skin cancers, with a more favorable prognosis.

Protocol for the examination of specimens from patients with carcinomas of the anus and anal canal: a basis for checklists. Cancer Committee of the College of American Pathologists

No Abstract Available

Sphincter preservation with chemoradiation in anal canal carcinoma: abdominoperineal resection in selected cases?

PURPOSE

This study contained herein assessed long-term results, toxicity, and prognostic variables following combined modality therapy of patients with International Union Against (Cancer Classification T1-4, N0-3, M0 squamous-cell carcinoma of the anal canal.

PATIENTS AND METHODS

Between 1985 and 1996, 62 patients completed treatment with combined modality therapy. A median total dose of 50 Gy was given to the primary, perirectal, presacral, and inguinal nodes followed by a local boost in selected cases. 5-Fluorouracil was scheduled as a continuous infusion of 1,000 mg/m2 per 24 hours on days 1 to 5 and 29 to 33 and mitomycin C as a bolus of 10 mg/m2 on days 1 and 29. Routinely processed paraffin-embedded sections were stained using monoclonal antibodies for detection of proliferating cell nuclear antigen and MIB1 (Ki-67) antigen to determine the labeling index. In addition, DNA ploidy was assessed after Feulgen staining.

RESULTS

Actuarial cancer-related survival, no evidence of disease survival, and colostomy-free survival rates at five years were 81, 76, and 86 percent, respectively. In univariate analysis, T category (T1/2 vs. T3/4) was predictive for no evidence of disease survival (87 vs. 59 percent; P = 0.03) and colostomy-free survival (94 vs. 73 percent; P = 0.05). N category (N0 vs. N1-3) influenced actuarial cancer-related survival (85 vs. 58 percent; P = 0.002) and no evidence of disease survival (80 vs. 53 percent; P = 0.02). A higher proliferative potential as measured by the MIB1 labeling index was associated with a better colostomy-free survival (90 vs. 50 percent; P = 0.04). In multivariate analysis, actuarial cancer-related survival was only influenced by the N category (P = 0.03) and no evidence of disease survival by N category (P = 0.03) and mitomycin C dose (P = 0.04). Salvage abdominoperineal resection achieved long-term control in only four of seven patients with local failures.

CONCLUSION

Treatment with a combination of radiotherapy and chemotherapy is safe and effective for patients with anal canal carcinoma. Abdominoperineal resection is indicated as a salvage procedure in nonresponding and recurrent lesions and may be of benefit in a small subgroup of patients with poor prognostic factors.

Perianal basal cell carcinoma: a comparative histologic, immunohistochemical, and flow cytometric study with basaloid carcinoma of the anus

Perianal basal cell carcinoma is a very rare tumor accounting for only 0.2% of the anorectal tumors. It must be distinguished from basaloid carcinoma of the anus, which resembles it histologically but shows a much more aggressive behavior, metastasizes early, and often proves fatal, thus requiring different therapy. Differential diagnosis of both entities by light microscopy may be difficult. Five cases of perianal basal cell carcinoma and five cases of basaloid carcinoma were studied by means of immunohistochemistry and flow cytometry. Some immunohistochemical markers, such as epithelial membrane antigen, carcinoembrionic antigen, and keratins, as well as the lectin Ulex europaeus agglutinin I stained basaloid carcinoma and were negative for basal cell carcinoma. In contrast, the monoclonal antibody Ber-EP4 seems to be a good marker for perianal basal cell carcinoma and useful in differentiating it from basaloid carcinoma of the anus. Basaloid carcinomas are associated with a significantly higher S-phase fraction than are perianal basal cell carcinomas (p < 0.01).

Neoplasms of the anus

Anal cancers can be grouped into three major categories. First, anal margin lesions are usually well-differentiated, keratinized squamous cell carcinomas that are amenable to local treatment measures. Second, anal canal cancers distal to the dentate line are mostly epidermoid, nonkeratinizing, moderately differentiated tumors. They are usually best treated with a multimodality approach using chemoradiotherapy and reserving surgery for clinical failures. Third, cancers arising in the ATZ are usually adenocarcinomas, and their treatment depends upon local factors. APR is in order for locally aggressive lesions, but newer protocols are studying multimodality therapy for this entity as well. Other, less common cancers of this region should be evaluated based upon their biologic potential and local involvement, with treatments selected accordingly.

Anal carcinoma--a histological review

Epidemiological evidence of an association between anal carcinoma and symptomatic HIV-related disease suggests that the number of cases of this disease may increase significantly over the next few years. The role of oncogenic HPV types in the pathogenesis of anal carcinoma is substantiated by both epidemiological evidence that tumours are associated with a past history of anal warts and by experimental evidence showing that over 85% of tumours contain HPV 16/18 DNA on PCR. The physical state of the virus in the tumour cell genome is currently under investigation, and cellular interactions between HPV, HIV and other sexually transmitted viruses require further research. Clinical studies have shown that patients with anal warts and those who are HIV positive also show an increased tendency to develop dysplasia within the anal epithelium. However, the malignant potential of dysplasia remains unclear and, it presents problems in management, particularly when multifocal and high grade. Problems in classification of anal carcinomas involve both the site of the tumours and the histological appearance. Despite the difficulties which exist in estimating the origin of a tumour from canal or margin, this information does appear to have clinical significance and should therefore continue to be assessed. Recent morphological and keratin studies have emphasized the heterogeneity of these tumours and have revealed a similar heterogeneous profile of keratin expression in the normal anal epithelium. These results support the body of opinion which suggests that, with the exception of small cell carcinoma and adenocarcinoma, anal carcinomas should be considered as squamous cell tumours which are able to display a range of further morphological characteristics within which ductal differentiation and mucin production appear to carry the worst prognosis. Although there is no universally accepted staging system for anal carcinoma, depth of invasion and extent of spread at the time of diagnosis are the most important clinical factors determining survival and response to therapy. Randomized clinical trials are now under way to compare the outcome of various combinations of radiotherapy and chemotherapy, which have replaced radical surgery as a first line treatment and resulted in a significant decrease in patient morbidity from this disease.

Recurrent squamous cell carcinoma of the anal canal. Predictors of initial treatment failure and results of salvage therapy

OBJECTIVE

The outcomes of patients with squamous cell carcinoma of the anal canal treated by either sphincter-preserving procedures or radical surgery were evaluated, with the goals of identifying factors predicting treatment failure and quantifying results of salvage therapy in patients with recurrent disease.

BASIC PROCEDURES

A population-based study on all patients in all 159 hospitals of the Department of Veterans Affairs (VA) from 1987 to 1991 was carried out. Data were compiled from several national computerized VA data sets. Supplementary information from local tumor registrars also was obtained, including demographic information, discharge summaries, operative reports, pathology reports, and medical oncology and radiation oncology summaries. From these sources, information on tumor histology, tumor stage, tumor grade, presence of regional or distant metastases, surgical procedures, use of chemotherapy and radiation therapy (RT), toxicity of chemotherapy and RT, development of recurrent disease, treatment of recurrence, survival, and cause of death were obtained.

MAIN FINDINGS

Four hundred five patients with anal cancer were identified by computer search, and 204 (51%) were evaluable; 164 of 204 (80%) had squamous cell carcinoma, 137 of whom (84%) were treated with sphincter-preserving procedures, and 27 of whom (16%) were treated by by radical surgery. One hundred fourteen of 138 (83%) were treated by multimodality therapy, which we defined as local excision followed by chemotherapy and RT. The mean dose of RT among patients treated by multimodality therapy was 4200 +/- 540 cGy and 82% of those treated with multimodality therapy received 5-FU/mitomycin C. Recurrent disease was diagnosed in 43 of all 149 patients (29%) with potentially curable disease. (stages I-III) Multivariate analysis revealed that stage at diagnosis (p = 0.04) and method of treatment (p = 0.03) were the sole predictors of recurrence. Fifty-three percent of patients who underwent salvage abdominoperineal resection (APR) are alive, whereas only 19% who underwent salvage chemotherapy with or without RT are alive.

PRINCIPAL CONCLUSIONS

These data indicate that multimodality therapy currently is being employed in the majority of patients with squamous cell carcinoma of the anal canal in the VA system. Tumor stage and method of treatment appear to affect the likelihood of development of recurrent disease. Salvage APR has curative potential. Results with salvage chemotherapy and RT are disappointing.

Malignant anal tumours

Anal tumours represent 5 per cent of anorectal cancers and exist as two clinical entities: tumours of the anal canal and those of the anal margin. Smoking and sexual behaviour, particularly homosexual anal intercourse, are important aetiological factors. This association is related to anal warts and human papillomavirus infection, notably type 16, which is found in around 70 per cent of warts. Symptoms are non-specific and are frequently attributed to benign conditions. Rectal examination reveals a characteristically infiltrating lesion and any suspicious anal area should be biopsied. There are two histological types. Squamous carcinoma comprises approximately 95 per cent of anal tumours and includes the 35 per cent of tumours derived from the anal transition zone (cloacogenic tumours), containing a mixture of squamous and mucinous elements. The remaining 5 per cent of anal tumours are adenocarcinoma. Squamous cell tumours of the anal canal are probably best treated using radiotherapy (with chemotherapy) as complete response rates, 5-year survival rates, and incidences of normal sphincter function and significant toxicity are around 80, 70, 75 and 20 per cent respectively. Treatment failures may be salvaged by surgery. The 5-year survival and local recurrence rates for radical surgery are around 60 and 25 per cent respectively; there are few indications for local excision. In contrast, 60 per cent of anal margin tumours are suitable for local excision, the 5-year survival rate being in excess of 80 per cent. Combining radiotherapy with surgery may give additional benefit. Current randomized controlled trials should further clarify the relative merits and demerits of the treatment options.

Diagnosis and treatment of anal carcinoma. An overview

Squamous cell carcinoma of the anal canal gives early symptoms and is easy to diagnose. However, these patients often present with advanced tumours, probably because of patient's and/or doctor's delay. The diagnosis must be confirmed by a conclusive biopsy as the treatment of ano-rectal tumours is based upon correct histopathological diagnosis. Loco-regional tumour control of squamous cell carcinoma is excellent following radiotherapy or combined chemoradiotherapy as only 10-20% of the patients develop a local recurrence. The great majority of these are cured by abdominoperineal resection. However, this treatment involves considerable acute and chronic toxicity, but mortality is less than 2%. There is no general agreement about how to minimize toxicity without hazarding loco-regional tumour control. One way could be to irradiate only the primary tumour site in patients with early lesions, and reserve radiotherapy of regional lymph nodes for more advanced cases. About 20% of the patients develop distant metastases, which make the disease incurable. Hence, frequent, rectal digital examination is the most important follow-up since early local recurrences can easily be cured. There is no general consensus concerning adjuvant chemotherapy, but its potential should be further explored.