Data recently published in The Lancet outlining analysis of over 8,000 patients, suggest that radiation in addition to surgery, either pre or postoperatively, reduces the risk of a local cancer recurrence and death from rectal cancer.
Standard treatment of rectal cancer involves surgery and often results in apparent curative resection (surgical removal of all evident cancer). Despite apparently curative surgery, rectal cancer recurs locally in up to 25% of patients.
The Colorectal Cancer Collaborative Group performed collaborative meta-analysis on 22 randomized trials that compared the outcomes of surgery alone with the outcomes of surgery combined with preoperative radiotherapy (6,530 patients in 14 trials) or postoperative radiotherapy (2,157 patients in 8 trials).
Radiotherapy before or after surgery substantially reduced the risk of a local recurrence in apparently curative resected patients. The yearly risk of local recurrence was 46% lower in patients receiving adjuvant radiotherapy prior to surgery than in surgery alone. Likewise, the yearly risk of local recurrence was 37% lower in patients receiving postoperative radiotherapy than in patients undergoing surgery alone.
The largest reduction in local recurrence was found in patients treated with preoperative radiotherapy of higher doses (biologically effective doses of 30 Gy or more). Radiotherapy with lower doses displayed no significant reductions in local recurrence. Postoperative radiotherapy also reduced local recurrence, but treatment schedules are longer and do not appear any more effective than short, preoperative treatment.
Despite the reduced risk of recurrences, the overall survival rate only slightly increased for patients receiving radiotherapy in addition to surgery. Survival at 5 and 10 years following treatment for patients treated with adjuvant radiotherapy was 45% and 26.9% respectively, compared to 42.1% and 25.3% for patients undergoing surgery alone. Patients undergoing radiotherapy had a substantially higher risk of death from causes unrelated to rectal cancer. This risk was highest for patients treated with preoperative radiotherapy using higher doses and resulted in early death within one year of treatment. It is important to note that these studies were small and most used a type of radiotherapy that irradiates large volumes of healthy tissue in addition to cancerous tissue. The use of radiotherapy with improved delivery specificity (radiation targeting less healthy tissue) may reduce these non-cancer related deaths and a corresponding increase in survival with adjuvant therapy may occur.
This study suggests that radiotherapy in addition to surgery (either pre or postoperatively) for rectal cancer reduces local recurrences and cancer-related deaths. However, due to increased non-cancer related deaths from radiation-induced complications, significant overall survival benefits were offset in patients receiving radiation. With the use of more sophisticated radiation delivery methods and improved supportive care, an increase in long-term survival may be achieved with the addition of radiation to surgery in rectal cancer patients. Patients with rectal cancer may wish to speak with their physician about the risks and benefits of radiation therapy in addition to surgery or clinical trials further evaluating this issue. Two sources of information regarding ongoing clinical trials include comprehensive, easy-to-use listing services provided by the National Cancer Institute (cancer.gov) and www.eCancerTrials.com. eCancerTrials.com also provides personalized clinical trial searches on behalf of patients. (The Lancet, Vol 358, No 9290, pp.1291-1304, 2001)
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