Advances in the treatment of early- to late-stage colorectal cancer: 20 years of progress

Colorectal tumors and hepatic metastases differ in their optical properties—relevance for dosimetry in laser-induced interstitial thermotherapy

BACKGROUND AND OBJECTIVES

The therapeutic application of laser light is a promising alternative to surgical resection of colorectal liver metastases. The extent of tumor destruction achieved by this strategy depends primarily on light distribution in the target tissue. Knowledge about optical properties is necessary to predict light distribution in the tissue for careful irradiation planning. The aim of this study was to compare the optical behavior of healthy colon tissue with that of colorectal carcinomas and their hepatic metastases in the native and coagulated state in order to test the effect of malignant degeneration, metastasis, and thermal coagulation on optical parameters.

MATERIALS AND METHODS

Ninety tissue samples were taken from patients with a colorectal carcinoma and concomitant liver metastases: healthy colon tissue (n = 30); colon carcinoma (n = 30); liver metastases (n = 30). Optical properties were measured according to the single integrating sphere principle in the native state and after thermal coagulation in the wavelength range of 800-1,100 nm and analyzed by inverse Monte Carlo simulation.

RESULTS

The highest optical penetration depth for all tissue types was obtained at the end of the spectral range investigated. The highest penetration depths of 4.13 mm (healthy colon), 7.47 mm (colon carcinoma tissue), and 4.08 (liver metastases) were at 1,060 nm, although the values decreased significantly after thermal coagulation. Comparing healthy colon-to-colon carcinoma always revealed a significantly lower absorption and scattering coefficient in the tumor tissue. This resulted in a higher optical penetration depth of the laser light in the colon carcinoma tissue (P < 0.05). A direct comparison disclosed no agreement between the optical properties of the primary tumor and the liver metastases. In the native state, colon carcinoma tissue had a lower scattering coefficient (P < 0.05), higher anisotropy factor, and optical penetration depth than liver metastases (P < 0.05). The absorption coefficient did not differ significantly. The differences in the native state were equalized by tissue coagulation.

CONCLUSIONS

Colon carcinoma tissue has a higher optical penetration depth than healthy colon tissue, which speaks in favor of tumor selectivity for interstitial laser application, since large treatment volumes can be obtained in the tumor. The lack of agreement between primary tumors and their concomitant liver metastases indicates a modification of optical behavior through metastasis. Thermal coagulation of tissue leads to changes in the optical properties, which are clearly less pronounced in carcinoma tissue. The data obtained in this study clearly show that an individual irradiation schedule is necessary for effective and safe dosimetry in laser-induced thermotherapy (LITT).

Expression of proliferating cell nuclear antigen and CD44 variant exon 6 in primary tumors and corresponding lymph node metastases of colorectal carcinoma with Dukes' stage C or D

AIM: To study changes in characteristics of colorectal carcinoma during the metastatic process and to investigate the correlation between cell proliferation activity and metastatic ability of patients with Dukes’ stage C or D.

METHODS: Formalin fixed and paraffin embedded materials of primary tumors and corresponding lymph node metastases resected from 56 patients with Dukes' stage C or D of colorectal carcinoma were stained immunohistochemically with proliferating cell nuclear antigen (PCNA) and CD44 variant exon 6 (CD44v6).

RESULTS: Thirty-one of 56 patients (55.4%) expressed PCNA in the primary sites and 36 of 56 patients (64.3%) expressed PCNA in the metastatic lymph nodes. A significant relation in PCNA expression was observed between the primary site and the metastatic lymph node (0.010 < P < 0.025). Forty-one of 56 patients (73.2%) expressed CD44v6 in the primary site and 39 of 56 patients (69.6%) expressed CD44v6 in the metastatic lymph node. There was also an significant relationship of CD44v6 between the primary site and the metastatic lymph node (0.005 < P < 0.010). No difference was observed between expression of CD44v6 and PCNA in the primary site (0.250 < P < 0.500).

CONCLUSION: This study partially demonstrates that tumor cells in metastatic lymph node of colorectal carcinoma still possess cell proliferation activity and metastatic ability of tumor cells in primary site. There may be no association between cell proliferation activity and metastatic ability in colorectal carcinoma.

A Critical Appraisal of Treatment for T3N0 Colon Cancer

The purpose of this study was to evaluate the impact of adjuvant chemotherapy on survival after surgery for T3N0 colon cancer. All patients with node-negative (N0) colon cancer with tumor invasion beyond the muscularis propria (T3) treated with colectomy between 1982 and 1995 at a single institution were included. Patients were divided into two groups depending on postcolectomy treatment with or without adjuvant chemotherapy. Groups were evaluated to determine perioperative and pathologic variables that could potentially influence outcome and surveillance data to determine disease-free and overall survival. In 253 patients with T3N0 colon cancer 226 remained under observation and 27 were treated with adjuvant chemotherapy. The groups were similar ( P = not significant) when compared for tumor location, size, differentiation, number of nodes harvested, and transfusion requirements. Four of the 27 patients who received chemotherapy developed a recurrence (14.8%), whereas 22 of the 226 observation patients developed a recurrence (9.7%). Disease-free survival for the chemotherapy group at 5 years was 84 per cent and for the observation group 87 per cent. Statistical analysis (Mantel-Cox) showed no significant difference between the groups on the basis of survival ( P = 0.3743). We conclude that resection alone is a highly effective treatment for T3N0 colon cancer leaving limited opportunity for adjuvant chemotherapy to significantly impact survival. Adjuvant chemotherapy for T3N0 colon cancer patients should be limited to patients enrolled in clinical trials designed to identify subgroups of T3N0 colon cancer patients at a survival disadvantage or less toxic adjuvant chemotherapies.

Selection of patients for resection of colorectal metastases to the liver using diagnostic laparoscopy and laparoscopic ultrasonography

OBJECTIVE

To assess the value of diagnostic laparoscopy (DL) and laparoscopic ultrasonography (LUS) in the staging and selection of patients with colorectal liver metastasis.

SUMMARY BACKGROUND DATA

Preoperative imaging modalities such as ultrasound, computed tomography, and magnetic resonance imaging are limited in the assessment of the number and exact location of hepatic metastases and in the detection of extrahepatic metastatic disease. Consequently, the surgeon is often faced with a discrepancy between preoperative imaging results and perioperative findings, resulting in either a different resection than planned or no resection at all.

METHODS

Fifty consecutive patients were planned for DL and LUS in a separate surgical sitting to assess the resectability of their liver metastases. All patients were considered to be candidates for resection on the basis of preoperative imaging studies.

RESULTS

Laparoscopy could not be performed in 3 of the 50 patients because of dense adhesions. The remaining 47 patients underwent DL. On the basis of DL and LUS, 18 (38%) patients were ruled out as candidates for resection. Of the 29 patients who subsequently underwent open exploration and intraoperative ultrasonography, another 6 (13%) were deemed to have unresectable disease.

CONCLUSIONS

The combination of DL and LUS significantly improves the selection of candidates for resection of colorectal liver metastases and effectively reduces the number of unnecessary laparotomies.

Resection of brain metastases from colorectal carcinoma in 73 patients

BACKGROUND

At the time of diagnosis of colorectal carcinoma, 2-3% of patients are likely to be harboring brain metastases, and another 10% of patients will develop brain lesions during the course of their disease. The purpose of this study was to examine the clinical course of a group of patients with metastatic brain disease who underwent surgical resection in a single institution. The authors believe this information will be useful for establishing prognostic factors and for clinical decision making.

METHODS

Between 1974 and 1993, 709 consecutive patients underwent surgical resection of brain metastases at Memorial Sloan-Kettering Cancer Center. Seventy-three patients had histologically confirmed colorectal carcinoma. The medical records of these patients were reviewed retrospectively, and the data were analyzed by univariate and multivariate analysis.

RESULTS

The median age of the 43 women and 30 men was 61.5 years. The median interval from the time of diagnosis of the primary tumor and the development of brain metastases was 27.6 months. The primary colorectal tumor was resected in all patients, and the median survival from the day of surgery was 38 months. The median survival from the time of craniotomy was 8.3 months. The 1-year and 2-year survival rates were 31.5% and 6.8%, respectively. Postoperative mortality was 4%. Gender, presence of multiple metastases, presence of lung lesions, and adjuvant brain radiation after craniotomy appeared to have no impact on survival as determined by multivariate Cox analysis. Only the presence of cerebellar brain metastases was associated with decreased survival.

CONCLUSIONS

The results of this series, which the authors believe is the largest series of resected brain metastases from colorectal carcinoma published to date, indicate that surgical resection may increase the survival of these patients. Analysis of prognostic factors shows that infratentorial tumor location is associated with a poorer survival compared with supratentorial tumor location (5.1 months vs. 9.1 months; P < 0.002). In patients with recurrent brain disease, repeated resection is a worthwhile consideration because it may prolong survival compared with patients who do not undergo re-resection.

Radioimmunoguided surgery benefits for recurrent colorectal cancer

BACKGROUND

Despite new adjuvant therapy, 50% of patients with colon cancer will have recurrent disease. This study investigated the use of a radiolabeled monoclonal antibody in locating occult tumor during surgery for recurrent colorectal cancer.

METHODS

Twenty-two patients with recurrent colorectal cancer underwent surgery using the radioimmunoguided surgery (RIGS) system. All patients were subjected to abdominal and chest computed tomography (CT). Before surgery, patients were injected with the CC49 monoclonal antibody (MoAb), anti-TAG antibody labeled with 125I. Ten patients with elevated carcinoembryonic antigen (CEA) levels and no CT findings had a scintigraphy scan with an anti-CEA MoAb labeled with 99Tc. Human antimouse antibody levels of these patients were within normal limits. Surgical exploration including liver ultrasound examination was followed by survey with a gamma-detecting probe (GDP).

RESULTS

There was MoAb tumor localization in 100% of the patients. CT found nine tumor sites, traditional surgical exploration 30, and the GDP 51, with 44 confirmed by pathology (hematoxylin and eosin). The RIGS system found occult tumor in 10 patients (45.4%) and resulted in major changes in surgical procedure in 11 patients. In the 10 patients who had scintigraphy scans, 10 tumor sites were identified, whereas RIGS found an additional eight sites.

CONCLUSION

RIGS technology offers a substantial benefit for patients undergoing surgery for recurrent colorectal cancer and a better chance of finding recurrent tumor intraoperatively in patients who have elevated CEA levels with no other CT findings.

Metastatic colorectal cancer cells induce matrix metalloproteinase release by human monocytes

Matrix metalloproteinases-2 (MMP-2) and -9 (MMP-9) facilitate tumor invasion and metastasis via basement membrane degradation. In colorectal cancer (CRC) specimens, MMP production is largely stromal in origin, implicating monocytes (M phi s) and fibroblasts. We hypothesize that CRC cells induce stromal cell MMP production. This study examines the differential effect of metastatic and non-metastatic CRC cells on M phi MMP production. The human M phi line THP-1 was co-cultured with either a non-metastatic human CRC cell line (SW620-P) or a metastatic clone (SW620-S5) established by serial cecal transplantation of SW620-P in nude mice. Conditioned medium MMP activity and cellular MMP mRNA expression were assessed by gelatinase zymography and Northern blot analysis, respectively. Neither CRC line released MMP-2 or MMP-9. Isolated THP-1 M phi s produced basal levels of both MMP-2 and MMP-9. The level of MMP-9 activity was increased moderately by co-culture of M phi s with the metastatic SW620-S5 clone, but decreased by the non-metastatic SW620-P cells. MMP-2 activity was greatly augmented by co-culturing M phi s with SW620-S5 cells, but was not affected by SW620-P cells. The stimulatory effect of SW620-S5 cells on MMP-2 secretion was confirmed by Western blot analysis. Both isolated and co-cultured M phi s expressed MMP-2 mRNA while SW620-S5 cells under similar conditions did not, implicating M phi s as the source of increased MMP-2 activity. Since the induction of MMP-2 activity was not associated with a parallel increase in M phi MMP-2 mRNA, the modulation of M phi MMP-2 release appears to be post-transcriptionally regulated. Metastatic CRC cells are distinct from non-metastatic cells in their ability to induce M phi MMP release. This observation emphasizes the role of M phi-derived MMPs in facilitating CRC invasion and metastasis and suggests modulation of stromal cell MMP production by CRC cells in a paracrine fashion.