Development of new agents for the treatment of advanced colorectal cancer

Phase II Trial of Preoperative Chemoradiation With a Hyperfractionated Radiation Boost in Locally Advanced Rectal Cancer

PURPOSE

The purpose of this phase II study was to prospectively determine the efficacy of preoperative chemoradiation with a hyperfractionated (Hfx) RT boost to 61.8 Gy in locally advanced rectal cancer.

METHODS

Eligibility stipulated that the primary lesion had to be either T4; or T3 and >4 cm or 40% of the bowel circumference. Radiation (RT) consisted of 45 Gy to the pelvis (1.8 Gy per fraction) followed by 1.2 Gy twice daily (to the gross tumor volume) to a total RT dose of 61.8 Gy. There was 5-FU infused at 1 g/m2/24 hours for 4 days during the 1st and 6th weeks of RT (concurrent with the Hfx boost). Surgical resection was planned 4 to 6 weeks later. Adjuvant chemotherapy (bolus 5-FU/leucovorin) was scheduled for 4 cycles at 28-day intervals.

RESULTS

There were 22 patients, ages 22 to 81 years (median, 64) enrolled in the study. Of the 20 patients evaluable for response, 10 (50%) had evidence of clinical downstaging and 5 patients (25%) had > or =90% fibrosis in the resected specimen. With a median f/u of 40 months (7-158), the 4 years actuarial rate for all patients (n = 22) of OS was 64%, of DFS 62%, and of LC 84%. 3/21 patients (14%) had positive margins, all of whom developed a local failure (P < 0.001).

CONCLUSION

This regimen of high dose preoperative chemoRT with a Hfx RT boost (to 61.8 Gy) in patients with bulky, locally advanced rectal cancer results in clinical downstaging in half of the patients with significant fibrosis in the operative specimen.

In vitro detection of cross-resistant and non-cross-resistant agents with fluorouracil for patients with colorectal cancer

BACKGROUND

Fluorouracil-based chemotherapy, such as that with 5-fluorouracil (5-FU)/leucovorin, is standard as first-line chemotherapy for advanced colorectal cancer (CRC) in Japan. However, the best agent for second-line chemotherapy after fluorouracil failure is yet to be determined. This study was undertaken to find an appropriate agent for second-line chemotherapy.

METHODS

Seventy-five tumor specimens from CRC patients with no prior chemotherapy were obtained operatively and their chemosensitivity to five anticancer agents; i.e., 5-FU, mitomycin C (MMC), cisplatin, docetaxel, and an active metabolite of irinotecan (SN-38), was analyzed in an in vitro chemosensitivity test. In this method, the degree of chemosensitivity was expressed as the percent T/C ratio, where T was the total volume of the tumor colonies in the treated group and C was that of the control group. Pearson's correlation coefficients were used to assess the relationship between two agents.

RESULTS

Fifty-eight specimens (colon, 28; rectum, 30) were successfully analyzed. Positive correlations with 5-FU chemosensitivity were verified for the chemosensitivity of MMC, cisplatin, and docetaxel. No correlation with 5-FU chemosensitivity was verified for SN-38 chemosensitivity. Although the functional mechanism of each of the agents differs from that of 5-FU, with the exception of irinotecan, they all had a spectrum closely similar to the 5-FU spectrum.

CONCLUSION

Only irinotecan exhibited a spectrum independent of that of 5-FU, thus indicating that it could be an appropriate agent for second-line chemotherapy after fluorouracil failure.

Effect of surgical margin status on survival and site of recurrence after hepatic resection for colorectal metastases

OBJECTIVE

To evaluate the influence of surgical margin status on survival and site of recurrence in patients treated with hepatic resection for colorectal metastases.

METHODS

Using a multicenter database, 557 patients who underwent hepatic resection for colorectal metastases were identified. Demographics, operative data, pathologic margin status, site of recurrence (margin, other intrahepatic site, extrahepatic), and long-term survival data were collected and analyzed.

RESULTS

On final pathologic analysis, margin status was positive in 45 patients, and negative by 1 to 4 mm in 129, 5 to 9 mm in 85, and > or =1 cm in 298. At a median follow-up of 29 months, the 1-, 3-, and 5-year actuarial survival rates were 97%, 74%, and 58%; median survival was 74 months. Tumor size > or =5 cm, >3 tumor nodules, and carcinoembryonic antigen level >200 ng/mL predicted poor survival (all P < 0.05). Median survival was 49 months in patients with positive margins and not yet reached in patients with negative margins (P = 0.01). After hepatic resection, 225 (40.4%) patients had recurrence: 21 at the surgical margin, 56 at another intrahepatic site, 82 at an extrahepatic site, and 66 at both intrahepatic and extrahepatic sites. Patients with negative margins of 1 to 4 mm, 5 to 9 mm, and > or =1 cm had similar overall recurrence rates (P > 0.05). Patients with positive margins were more likely to have surgical margin recurrence (P = 0.003). Adverse preoperative biologic factors including tumor number greater than 3 (P = 0.01) and a preoperative CEA level greater than 200 ng/mL (P = 0.04) were associated with an increased risk of positive surgical margin.

CONCLUSIONS

A positive margin after resection of hepatic colorectal metastases is associated with adverse biologic factors and increased risk of surgical-margin recurrence. The width of a negative surgical margin does not affect survival, recurrence risk, or site of recurrence. A predicted margin of <1 cm after resection of hepatic colorectal metastases should not be used as an exclusion criterion for resection.