High-dose radiation therapy and neoadjuvant plus concomitant chemotherapy with 5-fluorouracil and cisplatin in patients with locally advanced squamous-cell anal canal cancer: final results of a phase II study

Chemotherapeutic options in the management of anal cancer

During the past two decades, anal cancer has served as a paradigm for the successful application of chemoradiation to solid tumours; so far, it remains one of the few carcinomas of the gastrointestinal tract which are curable without the need for definitive surgery. Since the original contribution by Nigro in 1974, surprisingly few changes have been made to the standard of care in chemotherapy, which still consists of a combination of 5-fluorouracil and mitomycin C. However, many issues have yet to be clarified, such as the potential role of cisplatin as a substitute to mitomycin, as well as treatment-induced toxicity in HIV-positive patients. In this paper, the management of patients with anal cancer is presented, and new chemotherapeutic options are critically reviewed. Finally, the authors' opinion regarding currently unresolved issues in the treatment of these rare neoplasms is expressed.

Treatment of squamous cell anal canal carcinoma (SCACC) with pulsed dose rate brachytherapy: A retrospective study

BACKGROUND AND PURPOSE

To evaluate the results of pulsed dose rate brachytherapy (PDR) in SCACC.

MATERIAL AND METHODS

From 1996 to 2002, 71 patients (pts) with SCACC were treated with PDR brachytherapy. The median age was 61.2 years (35-88), with a sex ratio of 1 M/6.5 F. The TNM classification was: 14 T1, 41 T2, 15 T3 and 1 T4, 52 N0, 13 N1, 3 N2 and 3 N3. All the pts were M0. Treatment started with external beam irradiation to the posterior pelvis (mean dose: 45.5 Gy). Forty-seven patients received chemotherapy (neoadjuvant/concomitant or both). After an interval of 2-6 weeks, PDR interstitial brachytherapy was performed. The mean dose was 17.8 Gy to the 85% reference isodose of the Paris system.

RESULTS

Treatment was interrupted in only one pt. With a median follow-up of 28.5 months, 2-year actuarial overall survival was 90%. Fourteen relapses occurred (four distant, three regional, and seven local). Ten patients developed a grade III complication (Lent Soma scale) and two a grade IV complication (colostomy or abdominal perineal resection for necrosis).

CONCLUSION

PDR appears to be an effective treatment for SCACC. It is capable of reproducing the results usually observed with continuous LDR.

Intensity-modulated radiation therapy (IMRT) in the treatment of anal cancer: toxicity and clinical outcome

PURPOSE

To assess survival, local control, and toxicity of intensity modulated radiation therapy (IMRT) in squamous cell carcinoma of the anal canal.

METHODS AND MATERIALS

Seventeen patients were treated with nine-field IMRT plans. Thirteen received concurrent 5-fluorouracil and mitomycin C, whereas 1 patient received 5-fluorouracil alone. Seven patients were planned with three-dimensional anteroposterior/posterior-anterior (AP/PA) fields for dosimetric comparison to IMRT.

RESULTS

Compared with AP/PA, IMRT reduced the mean and threshold doses to small bowel, bladder, and genitalia. Treatment was well tolerated, with no Grade > or =3 acute nonhematologic toxicity. There were no treatment breaks attributable to gastrointestinal or skin toxicity. Of patients who received mitomycin C, 38% experienced Grade 4 hematologic toxicity. IMRT did not afford bone marrow sparing, possibly resulting from the clinical decision to prescribe 45 Gy to the whole pelvis in most patients, vs. the Radiation Therapy Oncology Group-recommended 30.6 Gy whole pelvic dose. Three of 17 patients, who did not achieve a complete response, proceeded to an abdominoperineal resection and colostomy. At a median follow-up of 20.3 months, there were no other local failures. Two-year overall survival, disease-free survival, and colostomy-free survival are: 91%, 65%, and 82% respectively.

CONCLUSIONS

In this hypothesis-generating analysis, the acute toxicity and clinical outcome with IMRT in the treatment of anal cancer is encouraging. Compared with historical controls, local control is not compromised despite efforts to increase conformality and reduce normal structure dose.

Tumor site predicts outcome after radiochemotherapy in squamous-cell carcinoma of the anal region: long-term results of 101 patients

PURPOSE

This study was designed to assess the long-term results following radiochemotherapy in patients with anal squamous-cell carcinoma and to evaluate the impact of tumor location on response, survival, and colostomy-free survival.

PATIENTS AND METHODS

Between 1985 and 2001, a total of 101 patients with anal carcinoma were registered for curative treatment, of whom 77 had involvement of the anal canal alone, 10 cases had extension into the perianal skin, and 14 patients had pure anal margin tumors. Small tumors of the anal margin were not included since they were treated by surgical excision only. Among the 101 patients were 74 women and 27 men with a median age of 62 (range, 26-84) years. T categories (International Union against Cancer) were T1 (15), T2 (36), T3 (34), and T4 (16). Seventy-one patients had no evidence of nodal disease, whereas 30 presented with involved regional nodes. Radiation treatment was directed to the primary tumor region and to the inguinal, perirectal, and internal iliac nodes using a three-field to four-field box technique with 10MV photons up to a total dose of 5040 cGy. Lesions greater than 5 cm received an additional boost by interstitial or external radiation depending on circumferential extension of the residual tumor. All patients were scheduled for simultaneous chemotherapy with two cycles of 5-fluorouracil at a dose of 1000 mg/m (2)/day as 120 hours of continuous intravenous infusion on Days 1 to 5 and 29 to 33 and mitomycin C at 10 mg/m (2)/day on Days 1 and 29. Median follow-up time was was 7.5 (range, 1-16) years.

RESULTS

Overall survival and colostomy-free survival rates for patients with anal canal cancer were 75 percent and 87 percent at five years, respectively. Patients with anal margin cancer had a less favorable outcome with five-year-overall and colostomy-free survival rates of 54 percent and 69 percent, respectively. After correction for imbalance between anal canal and anal margin tumors, i.e., exclusion of T1 tumors of the anal canal, difference in overall survival remained significant (73 percent vs. 54 percent, P = 0.01). Following multivariate analysis, tumor location (anal canal vs. anal margin, P = 0.02), age (P = 0.003), and dose intensity of chemotherapy (< or =75 percent vs. >75 percent, P = 0.03) remained independent significant factors for overall survival. Initial tumor response at six weeks (P = 0.03) was predictive for colostomy-free survival.

CONCLUSIONS

With colostomy-free survival rates around 85 percent, long-term treatment results for anal canal carcinoma have reached a satisfactory level. However, patients with larger lesions of the perianal skin are at high risk for locoregional recurrence and possible treatment intensification in this subgroup seems desirable.

Anal carcinomas in HIV-positive patients: high-dose chemoradiotherapy is feasible in the era of highly active antiretroviral therapy

BACKGROUND

Anal carcinoma, a common disease in HIV-positive patients, is usually treated with chemoradiotherapy. Generally tolerance was poor before the availability of highly active antiretroviral therapies. We report our experience of treating anal carcinoma in the era of new antiviral drugs.

PATIENTS AND METHODS

Between 1997 and 2001, nine men on highly active antiretroviral therapies with good immune status before chemoradiotherapy received concomitant chemoradiotherapy consisting of 5-fluorouracil and cisplatinum, and high-dose radiotherapy (60-70 Gy) for anal carcinoma. Six cancers were Stage I, two were Stage II, and one was Stage III. CD4+ cell counts were <200/ml for four patients, between 200/ml and 500/ml for four, and >500/ml for one.

RESULTS

All patients received the planned dose of radiation (> or = 60 Gy). The chemotherapy dose was reduced 25 percent in six patients. Overall treatment time was 58 days. Grade 3 hematologic or skin toxicity occurred in four patients. No association was observed between high-grade toxicity and CD4+ cell count. None of the patients developed opportunistic infections during follow-up. Eight patients were disease-free after a median follow-up of 33 months. Among them, four had no or minor anal function impairment at the last follow-up visit. One patient with T4N2 disease relapsed locally one year after treatment and underwent salvage abdominoperineal excision.

CONCLUSION

High-dose chemoradiotherapy for anal carcinomas is feasible with low toxicity in HIV-positive patients treated with highly active antiretroviral therapies. Local control is similar to that obtained for HIV-negative patients.

Patterns of local disease failure and outcome after salvage surgery in patients with anal cancer

Background

Salvage surgery for anal cancer is usually reserved for local disease failure, but issues relating to the prediction of local failure and surgical outcome are ill defined.

Methods

Between 1988 and 2000, 254 patients with non-metastatic anal epidermoid carcinoma were treated at a regional cancer centre with radiotherapy (n = 127) or chemoradiotherapy (n = 127).

Results

There were 99 local disease failures (39·0 per cent), all but five occurring within 3 years of initial treatment. Increasing age (P &lt; 0·001, Cox model), total radiation dose (P = 0·004) and tumour stage (P = 0·010) were independent predictors of local failure. The overall 3- and 5-year survival rates after local disease failure were 46 and 29 per cent; the corresponding rates after salvage surgery (73 patients) were 55 and 40 per cent. A positive resection margin was the strongest negative predictor of survival after salvage surgery (P = 0·008, log rank test). Of 52 patients treated before the routine consideration of primary plastic reconstruction, delayed perineal wound healing occurred in 22 (42 per cent).

Conclusion

In the management of anal cancer, local disease failure is a major clinical problem requiring early detection followed by radical surgery, often accompanied by plastic reconstruction. By implication, these factors favour the centralization of treatment for this uncommon cancer to a multidisciplinary oncology team.

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.

Recent clinical trials summary

The current standard of care for the treatment of anal cancer as demonstrated by all of the completed phase 3 clinical trials remains 5-FU and mitomycin C in combination with radiation therapy. The basic elements of the approach outlined by Nigro have not changed in the last 30 years. Future phase 3 trials will serve to further perfect this approach and outline the role of HPV and dysplasia in the development and progression of this disease.

Contribution of conformal therapy in the treatment of anal canal carcinoma with combined chemotherapy and radiotherapy: results of a phase II study

PURPOSE

To evaluate the feasibility of delivering conformal radiotherapy (RT) and concurrent chemotherapy without a mandatory break in patients with anal canal carcinoma.

METHODS AND MATERIALS

Thirty patients with T2-T4 tumors were treated with a combination of 54 Gy in 30 fractions and two cycles of 5-fluorouracil and mitomycin C. Dose-volume histograms were obtained for bone marrow, small bowel, and skin to compare the conventional technique using the Radiation Therapy Oncology Group standard with our conformal technique.

RESULTS

The mean dose ratio of the conventional compared with the conformal technique for bone marrow, small bowel, and skin was, respectively, 2.1-2.7, 3.0, and 2.0, in favor of the conformal technique. All patients completed their treatment without a treatment break. An incidence of Grade 3 toxicity for bone marrow, bowel, and skin of 13.3%, 3.3%, and 20%, respectively, was observed. With a median follow-up of 33 months, a 4-year local recurrence-free survival rate of 91% was observed.

CONCLUSION

The results of this study have shown that conformal RT leads to a well-tolerated treatment. The treatment time is shortened to 6 weeks. A significant decrease in the acute toxicity rate suggests that by decreasing the "volume factor," conformal RT improves the therapeutic index in patients treated with combined chemotherapy and RT.

Anal cancer: an HIV-associated cancer

Although not yet included in the Centers for Disease Control definition of AIDS, anal cancer clearly occurs more commonly in HIV-infected patients. An effective screening program for those groups who are at highest risk might be expected to impact rates of anal cancer just as significantly as did cervical Pap screening programs for the incidence of cervical cancer. Despite a relatively low rate of progression from AIN to invasive cancer, the scope of the problem is enormous based on the prevalence of anal HPV infection and the size of the HIV-infected, at-risk population. Thus, the potential benefits of screening, detection, and the development of more effective therapy also are enormous. Currently, therapeutic HPV vaccines for AIN represent an exciting avenue of research in HPV-related anogenital disease. Invasive anal cancer and HSIL (which is believed to be the precursor lesion) are expected to become increasingly important health problems for both HIV-infected men and women as their life expectancy lengthens. Although HAART may have improved the ability of many to tolerate CMT, it appears that toxicity of this therapy continues to be a problem for a proportion of HIV-infected subjects. The acute side effects present specific challenges to the clinician and patient, have an immediate impact on the patient's plan of care and dose intensity of the treatment, and ultimately may impact the outcome of the planned treatment. Late toxicity may influence the long-term quality of life. Small patient numbers, variable radiation therapy doses, limited information about viral load, and a potential confounding effect of higher CD4+ levels make it difficult to draw any conclusions about the effect of HAART on anal cancer outcome. Large, prospective studies will be required before solid conclusions about the impact of various factors on anal cancer prognosis and outcome can be drawn.

Anal neoplasms

A common theme in most anal neoplasms appears to be a delay in diagnosis due to confusion with more common, benign conditions. Thus, the clinician must maintain a high index of suspicion when evaluating lesions of the anal canal and margin. The use of primary chemoradiation for SCC of the anal canal has resulted in equivalent, if not superior, local control and survival compared with radical surgery, and results in sphincter preservation in over two thirds of cases. Nevertheless, abdominoperineal resection still plays an important role in salvage of treatment failures, and also for patients who are unlikely to tolerate chemoradiation or have pre-existing impaired continence. Recent studies indicate that variations in chemotherapeutic agents and radiation technique might potentially produce even better results. The prognosis for anorectal melanoma, as well as for small cell and undifferentiated tumors, continues to be poor. Fortunately, these are relatively rare tumors.

The combined use of radiotherapy and chemotherapy in the treatment of solid tumours

Several clinical trials carried out during the last decade clearly show that concomitant radiotherapy and chemotherapy significantly improves local control in a variety of advanced solid tumours. In most of these trials, cisplatin alone or in combination with other drugs has been used. This has led to improved survival rates in head and neck, lung and cervical cancer. The interaction of radiotherapy with chemotherapy for these solid tumours appears to be schedule-dependent, as no such an improvement was observed with neo-adjuvant chemotherapy followed by radiotherapy in eight out of nine clinical trials in cervical cancer. A major advantage of this combined modality treatment is organ preservation possible for patients with advanced larynx or anal cancer. Major further improvement can be expected from the design and exploration of drugs that influence the pathways leading to cell death after irradiation. Examples include topoisomerase 1 (topo1) inhibitors, alkyl-lysophospholipids, epidermal growth factor receptor (EGFR) receptor inhibitors.