Where are we now with adjuvant therapy for rectal cancer?

Effect of adjuvant radiotherapy on local recurrence in stage II rectal cancer

BACKGROUND

Prospective trials have demonstrated that chemotherapy combined with radiotherapy decreases local recurrence rates in stage II and stage III rectal cancer. Some patients with stage II lesions, however, have relatively low risks of local recurrence. We evaluated the effect of radiotherapy on local recurrence in patients with stage IIA rectal cancer.

METHODS

From the colorectal cancer database, we identified 390 stage IIA rectal cancer patients who underwent curative resection followed by adjuvant therapy from 1995 to 2002; a total of 72 patients who received preoperative chemoradiotherapy and who did not receive adjuvant therapy were excluded. Mean follow-up period was 65 months (range, 2-133 months).

RESULTS

Of the 390 patients, 110 had primary tumors in the upper rectum, 136 in the midrectum, and 144 in the lower rectum. Lymphovascular invasion was observed in 35 patients (9.0%). Mean (+/- SD) number of examined lymph nodes was 18 (+/- 12). Adjuvant chemotherapy was provided to 180 patients (46.2%), and chemotherapy plus radiotherapy was provided to 210 patients (53.8%). Radiotherapy was significantly more common in younger patients (P = .01) and those with lower rectal cancer (P < .001). Local recurrence rate did not differ between patients who did and did not receive radiotherapy. In patients with mid and lower rectal cancer, the local recurrence rate was not affected by radiotherapy.

CONCLUSIONS

Radiotherapy did not seem to provide additional benefit in decreasing local recurrence rate of stage IIA rectal cancers. In selected patients, however, the role of radiotherapy needs to be carefully evaluated.

Current evidence does not support routine adjuvant radiotherapy for rectal cancer

BACKGROUND

There is widespread support in the published literature for routine adjuvant radiotherapy for rectal cancer.

METHODS

In the present paper, the current evidence regarding adjuvant radiotherapy is reviewed, particularly the most recent studies of preoperative radiotherapy (usually including patients with Stage I, II and III disease) and postoperative radiotherapy (usually for Stage II and III disease), and meta-analyses. Two questions in particular are addressed: Does radiotherapy improve survival when surgeons are able to achieve low local recurrence rates with surgery alone? Does radiotherapy improve patients' quality of life?

RESULTS

Radiotherapy has only been demonstrated to significantly improve survival in one individual study and one recent meta-analysis. The local recurrence rates in the no-radiotherapy arm of these studies were 27% and 21-36.5%, respectively. In more recent studies, with lower local recurrence rates reflecting modern surgical standards, no survival advantage has been found. It is currently unknown whether radiotherapy improves patients' quality of life. Studies have demonstrated that radiotherapy has acute and long-term detrimental effects on quality of life. While local recurrence can be very debilitating, it can also be asymptomatic, and the overall effect of the local recurrence statistics found in adjuvant therapy studies on quality of life has not been systematically investigated. The most recent studies demonstrate that 17-20 patients need to undergo adjuvant radiotherapy to prevent one local recurrence.

CONCLUSION

Current evidence does not support the widespread advocacy for routine adjuvant radiotherapy as used in the treatment arms of recent trials.

Local recurrence after curative resection of cancer of the rectum without total mesorectal excision

PURPOSE

The aim of this article was to examine local recurrence after curative resection for carcinoma of the rectum in which the surgical technique of total mesorectal excision was not performed.

METHODS

A single surgeon managed the patients and the data collected prospectively. Total excision of the distal mesorectum was not performed in the upper third or mid rectum.

RESULTS

From 1969 to 1993 curative resections were performed in 549 patients, of which 17 died postoperatively, leaving 532 for analysis. Sphincter-saving resection was performed in 468 patients (88 percent) and abdominoperineal excision in 58 (10.9 percent). The pathology stages (Dukes) were A, 158 (29.7 percent); B, 184 (34.7 percent); and C, 190 (35.7 percent). Five hundred seventeen patients (97.2 percent) were followed up for a minimum of five years. The median period of follow-up was 82 months. Local recurrence confined to the pelvis occurred in 17 patients, and local recurrence associated with distant metastases occurred in 24 patients. The total five-year local recurrence rate was 7.6 percent. Local recurrence was increased in Stage C tumors (P = <0.0001). Diathermy dissection in the pelvis was associated with a decreased local recurrence rate (P = 0.023). The five-year survival rate in curative resections was 72.5 percent.

CONCLUSIONS

It is essential that articles presenting local recurrence rates should include both local recurrence in isolation and that which occurs with distant metastases. Although total mesorectal excision for rectal cancer was not performed in this study, the local recurrence rate is not materially different from that in several articles where total mesorectal excision has been used. Whether the distal mesorectum needs to be pursued in mid-rectal cancer is not yet proven.

Rectal cancer: changing patterns of referral for radiation therapy 1982-1997

BACKGROUND

The purpose of the present study was to evaluate the changing role of radiation therapy in rectal cancer and to determine the patterns of referral of patients during a 15-year period.

METHODS

From 1982 to 1997, 464 patients with carcinoma of the rectum were referred to the Department of Radiation Oncology, Royal Prince Alfred Hospital: 79% of patients had locoregional disease alone and 21% had distant metastasis. Radiation therapy consisted of irradiation (definitive or palliative) alone to the primary tumour in 9.7% of cases; preoperative radiation in 7.3% of cases: preoperative chemoradiation in 7.5% of patients: postoperative radiation in 15.3% of patients: postoperative chemoradiation in 12.31% of patients: treatment of pelvic recurrence in 23.5% of patients and treatment of metastases in 9.1% of patients. The remainder were treated elsewhere (1.9%) or not treated (13.4%).

RESULTS

There was an average annual 14% increase in referrals over the accrual period. Recurrent rectal cancer decreased from approximately 30% of referrals during 1982-91 to approximately 10% in 1995-7. The use of postoperative adjuvant radiation reached a peak of 50% in 1993. The use of preoperative radiation increased suddenly in 1994 from < 10% to a sustained rate of approximately 30% of referrals. The use of chemoradiation commenced in 1990 for postoperative adjuvant treatment and in 1994 for preoperative treatment. The median survival time from initial diagnosis was 35 months, with 2- and 5-year survival rates of 62 and 28%, respectively. Survivals at 5 years for patients treated with preoperative and postoperative radiation (with or without chemotherapy) and with recurrent disease were 56, 44 and 21%, respectively.

CONCLUSIONS

The present study illustrates the changing role of radiation therapy in the management of rectal cancer. The increase in referrals over the observation period was due to increased multidisciplinary input into the initial management of these patients, based on reported clinical trials. The steady increase in the use of adjuvant therapy has paralleled a decrease in referrals for treatment of recurrence and reflects current clinical results. The sequencing of adjuvant therapy is changing currently, with greater emphasis on preoperative adjuvant treatment. Currently most adjuvant therapy includes chemotherapy.