How Safe is Adjuvant Chemotherapy and Radiotherapy for Rectal Cancer?

Late adverse effects of short-course preoperative radiotherapy in rectal cancer

Background

Preoperative radiotherapy improves local control and survival in rectal cancer, but there are few reports on long-term morbidity. The aims of this study were to compare long-term morbidity and quality of life in patients undergoing rectal cancer surgery with or without preoperative radiotherapy.

Methods

A total of 252 patients, randomized within the two Stockholm trials on preoperative radiotherapy in rectal cancer, were alive at a mean of 15 years after surgery. Some 139 of these patients were available for follow-up by questionnaires and clinical examination. Questionnaires regarding medical history and quality of life were completed by all patients. All patients had a clinical examination, and those without a stoma underwent rigid sigmoidoscopy.

Results

Overall, patients who had preoperative radiotherapy experienced significantly more late complications than those who did not (69 versus 43 per cent; P = 0·002). This morbidity consisted mainly of cardiovascular disease (35 versus 19 per cent; P = 0·032), faecal incontinence (12 of 21 versus 11 of 42 patients having anterior resection; P = 0·013) and urinary incontinence (45 versus 27 per cent; P = 0·023). No significant differences between groups were found for hip or pelvic fractures, small bowel obstruction or global quality of life.

Conclusion

Preoperative short-course, high-dose radiotherapy in patients with rectal cancer increases the risk of anal and urinary dysfunction, and may lead to increased cardiovascular morbidity, at long-term follow-up.

Towards therapeutic vaccines for colorectal carcinoma: a review of clinical trials

Colorectal carcinoma is a leading cause of cancer-related mortality. Despite the introduction of new cytotoxic drugs, improved surgical and radiotherapeutic techniques, a large proportion of colorectal carcinomas remain incurable. New targeted therapeutic strategies, including immunotherapy, are being explored as complementary treatments. Recent advances in immunology and molecular biology have opened new avenues for the clinical testing of rationally designed vaccination strategies against cancer. The present report reviews the results of therapeutic vaccine trials in colorectal carcinoma, published mainly in the past 6 years. Tumor-associated antigens (self-antigens) have been targeted by therapeutic vaccination in more than 2000 colorectal carcinoma patients. The results demonstrate that tumor antigen-specific immune responses are reproducibly induced; that is, tolerance can be reversed, without the induction of serious adverse events or autoimmune disorders. No long-term autoimmune side effects have been observed after a minimum follow-up of 4 years in over 700 patients. Over 1300 colorectal carcinoma patients with minimal residual disease have been enrolled in randomized controlled Phase II/III trials using autologous tumor cell vaccines. A significantly improved overall survival was noted for Stages I-IV colorectal carcinoma patients utilizing Newcastle-disease virus as an adjuvant. Autologous tumor cells mixed with bacillus Calmette-Guerin (BCG) were of significant clinical benefit for patients with Stage II colon cancer. Results of randomized controlled trials targeting Ep-CAM have shown clinical benefit in subgroups of patients. Several new generation vaccines have demonstrated excellent safety profile and immunogenicity. Some studies have also demonstrated a statistically significant correlation between the induced immune response and prolonged overall survival, which should be confirmed in enlarged trials. Although it is unlikely that active specific immunotherapy will provide a standard complementary therapeutic approach for colorectal carcinoma in the near future, the results so far are encouraging. Randomized controlled vaccine trials targeting molecularly defined tumor antigens are warranted, particularly in colon carcinoma with minimal residual disease.

Preoperative chemoradiation for rectal cancer causes prolonged pudendal nerve terminal motor latency

PURPOSE

A worsened anorectal function after chemoradiation for high-risk rectal cancer is often attributed to radiation damage of the anorectum and pelvic floor. Its impact on pudendal nerve function is unclear. This prospective study evaluated the short-term effect of preoperative combined chemoradiation on anorectal physiologic and pudendal nerve function.

METHODS

Sixty-six patients (39 men, 27 women) with localized resectable (T3, T4, or N1) rectal cancer were included in the study. All patients received 45 Gy (1.8 Gy/day in 25 fractions) over five weeks, plus 5-fluorouracil (350 mg/m2/day) and leucovorin (20 mg/m2/day) concurrently on days 1 to 5 and 29 to 33. Patients who had rectal cancer with a distal margin within 6 cm of the anal verge had the anus included in the field of radiotherapy (Group A, n = 26). Patients who had rectal cancer with a distal margin 6 to 12 cm from the anal verge had shielding of the anus during radiotherapy (Group B, n = 40). The Wexner continence score, anorectal manometry and pudendal nerve terminal motor latency were assessed at baseline and four weeks after completion of chemoradiation.

RESULTS

The median Wexner score deteriorated significantly (P < 0.0001) from 0 to 2.5 for both Groups A (range, 0-8) and B (range, 0-14). The maximum resting anal pressures were unchanged after chemoradiation. The maximum squeeze anal pressures were reduced (mean = 166.5-157.5 mmHg) after chemoradiation. This change was similar in both Groups A and B. Eighteen patients (Group A = 7, Group B = 11) developed prolonged pudendal nerve terminal motor latency after chemoradiation. These 18 patients similarly had a worsened median Wexner continence score (range, 0-3) and maximum squeeze anal pressures (mean = 165.5-144 mmHg). The results obtained were independent of tumor response to chemoradiation.

CONCLUSIONS

Preoperative chemoradiation for rectal cancer carries a significant risk of pudendal neuropathy, which might contribute to the incidence of fecal incontinence after restorative proctectomy for rectal cancer.