Systemic therapy for colorectal cancer: focus on newer chemotherapy and novel agents

The Effect of Adjuvant Chemotherapy on Stoma-Related Complications After Surgery for Colorectal Cancer: A Retrospective Analysis

PURPOSE

To assess stoma-related complications of colorectal cancer patients undergoing surgery with curative intent who received adjuvant chemotherapy compared to those who underwent surgery alone.

DESIGN

A retrospective analysis of a prospectively maintained colorectal cancer clinical audit database was completed.

SUBJECTS AND SETTINGS

Patients undergoing curative surgery for colorectal cancer with the formation of a stoma (end ileostomy, loop ileostomy, end colostomy) between 1999 and 2011 at a single hospital in Lanarkshire, United Kingdom. Patients who underwent neo-adjuvant chemotherapy were excluded. Two hundred twenty-two patients comprised the study sample; 130 (59%) were male. Seventy-five (34%) patients comprised the chemotherapy group and 147 (66%) made up the surgery-only group. Patients in the chemotherapy group were younger (61.6 vs 65.4 years; P = .001) and had higher stage colorectal cancer (P < .001). There was no difference in baseline (day 10) stoma scores between the chemotherapy or surgery-only groups.

METHODS

Postoperative stoma-related complications were serially assessed using a stoma complication scoring tool; scores were calculated at 10 days and 3 months postoperatively. Scores of patients receiving adjuvant chemotherapy were compared to scores of participants who underwent surgery alone.

INSTRUMENT

A composite stoma function score was calculated for each patient after assessment of stoma-related complications. The overall score included a global assessment of stoma quality (stoma retraction, prolapse, stenosis, parastomal hernia, skin changes) and patient-reported stoma function (leakage, soiling, nighttime emptying, odor).

RESULTS

At 3 months, the mean loop ileostomy stoma function score was poorer among the chemotherapy group when compared to the surgery-only group (4.55 vs 1.53; P = .041). No differences were found when colostomy (2.00 vs 2.62; P = .411) or end ileostomy (1.00 vs 2.00; P = .170) function scores were compared at 3 months.

CONCLUSION

Patients undergoing curative surgery for colorectal cancer resulting in a loop ileostomy who received adjuvant chemotherapy had higher stoma complication scores at 3 months compared to those who underwent surgery with no chemotherapy. This difference was not seen in patients with colostomies or end ileostomies. Patients, WOC nurses, and medical staff must be alert to the potential of increased loop ileostomy-related complications with adjuvant chemotherapy. Fully informed patient consent coupled with timely support and advice may reduce stoma-related morbidity and improve quality of life for such patients.

Impact of genetic profiles on the efficacy of anti-EGFR antibodies in metastatic colorectal cancer with KRAS mutation

Reports indicate that, even in KRAS-mutated colon cancer, there are subsets of patients who benefit from anti-EGFR monoclonal antibody (MoAb) treatment. The aim of the present study was to identify genetic profiles that contribute to the responsiveness of metastatic colorectal cancer (mCRC) to anti-EGFR MoAb. We retrospectively evaluated the efficacy of anti-EGFR MoAb in mCRC patients with KRAS mutations according to KRAS mutational subtypes, BRAF and PIK3CA mutational status and PTEN and MET expression. Among 21 patients with KRAS-mutant tumors, 8 (38%) harbored p.G13D, 7 (33%) harbored p.G12V, 5 (24%) harbored p.G12D, and 1 (5%) harbored p.G12C mutation. Patients with the p.G13D mutation exhibited a significantly higher disease control rate than patients with other KRAS mutations (P=0.042), and tended to show a longer progression-free survival (PFS) than patients with other KRAS mutations with marginal significance (P=0.074). Patients with loss of PTEN had significantly shorter PFS than those with normal PTEN expression in patients with KRAS mutations (P=0.044). MET overexpression was significantly associated with shorter PFS compared to normal MET expression in patients with KRAS mutations (P=0.016). Our data demonstrated the potential utility of alterations in PTEN and MET expression as predictive markers for response to anti-EGFR MoAbs in mCRC patients with KRAS mutations. In addition, we confirmed the predictive value of the KRAS p.G13D mutation for better response to anti-EGFR therapies in comparison with other KRAS mutations.

KRAS p.G13D mutation and codon 12 mutations are not created equal in predicting clinical outcomes of cetuximab in metastatic colorectal cancer: a systematic review and meta-analysis

BACKGROUND

The authors conducted a systematic review and meta-analysis to examine whether patients who had metastatic colorectal cancer (mCRC) with the v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS) p.G13D mutation (an amino acid substitution at position 13 in KRAS from a glycine to an aspartic acid) and received cetuximab treatment had better clinical outcomes than patients who had mCRC tumors with KRAS codon 12 mutations.

METHODS

Relevant studies were identified by a search of MEDLINE, EMBASE, the Chinese Biomedical Database, and Wan Fang Digital Journals from inception to October 2011. The primary clinical outcomes included the objective response rate (ORR), progression-free survival (PFS), and overall survival (OS). The pooled relative risk (RR) or hazard ratio (HR) was estimated by using fixed-effects or random-effects models according to heterogeneity between studies.

RESULTS

Ten studies were considered eligible that included 1487 patients with mCRC. Patients who had tumors with the KRAS p.G13D mutation had a significantly higher ORR (10 studies; RR, 1.642; 95% confidence interval [CI], 1.131-2.384), longer PFS (1 study; HR, 0.54; 95% CI, 0.36-0.81), and longer OS (1 study; HR, 0.52; 95% CI, 0.33-0.80) than patients who had tumors with KRAS codon 12 mutations. Compared with patients who had KRAS wild-type tumors, patients with the p.G13D mutation had a significantly lower ORR (9 studies; RR, 0.540; 95% CI, 0.381-0.765) and nonsignificantly shorter PFS (1 study; HR, 0.99; 95% CI, 0.68-1.45) and OS (1 study; HR, 1.01; 95% CI, 0.66-1.54).

CONCLUSIONS

Patients who had mCRC with the KRAS p.G13D mutation appeared to benefit more from cetuximab than patients who had tumors with KRAS codon 12 mutations. However, because of the limited sample sizes in the current meta-analysis, these results should be interpreted with caution.

A population-based analysis of second primary cancers after irradiation for rectal cancer

OBJECTIVE

To investigate the possible association between pelvic irradiation for rectal cancer and subsequent second primary cancers.

PATIENTS AND METHODS

A population-based analysis of 20,910 individuals with rectal cancer from the Surveillance, Epidemiology, and End Results registry, for whom follow-up times were at least 5 years, was performed. Kaplan-Meier estimates for the development of second cancers within irradiated and nonirradiated cohorts provided a comparison that accounted for censored data. Cox proportional hazards analyses were further conducted to compensate for patient and tumor-related factors.

RESULTS

A total of 656 (12%) and 2368 (16%) second primary cancers were enumerated from the irradiated and nonirradiated cohorts, respectively, with the proportion of second primary cancers within the irradiated cohort being significantly decreased (P < 0.001) on crude analysis. However, Kaplan-Meier and Cox analyses revealed no significant difference between the 2 cohorts when all second primary cancer sites were considered together (hazard ratio = 1.02; 95% confidence interval [CI], 0.92-1.12). Proportional hazards analysis for specific second primary sites revealed a decreased risk after pelvic irradiation for cancer of the prostate (hazard ratio = 0.63; 95% CI, 0.48-0.84), and an increased risk for cancers of the uterine corpus & cervix (hazard ratio = 2.5; 95% CI, 1.6-4.0).

CONCLUSION

Second primary cancers after irradiation for rectal cancers appear relatively infrequent compared with the background incidence of spontaneous cancers, and should not factor into treatment decisions for this older population. We hypothesize that the incidence of second primary tumors within adjacent organs could represent a balance between the radiation-induction of tumors and the radiation-inhibition of spontaneously occurring tumors.

Sequential administration of irinotecan and cytarabine in the treatment of relapsed and refractory acute myeloid leukemia

PURPOSE

Based on reported synergy of the topoisomerase-I (topo-I) inhibitor irinotecan with antimetabolites, irinotecan and cytarabine (Ara-C) were administered sequentially to patients with acute myeloid leukemia (AML) refractory to or relapsed following high-dose Ara-C and anthracycline therapy. Pharmacokinetic and pharmacodynamic studies were performed with the first irinotecan dose.

EXPERIMENTAL DESIGN

In vitro synergy of irinotecan followed by Ara-C was confirmed in a human AML cell line as a basis for the clinical trial. Irinotecan was administered daily for 5 days, with Ara-C 1 g/m2 12 h after each irinotecan dose. Irinotecan was initiated at 5 mg/m2, and the dose was escalated by 5 mg/m2 increments in cohorts of three patients and in individual patients. Pre-treatment samples were studied for topo-I activity and serial samples after the first irinotecan dose were analyzed for pharmacokinetics and for pharmacodynamic effects, including DNA damage and DNA synthesis rate.

RESULTS

The irinotecan dose reached 15 mg/m2 in three-patient cohorts without reaching the maximum tolerated dose, and reached 30 mg/m2 in individual patients. The AUC and Cmax of both irinotecan and its active metabolite SN38 increased linearly in proportion to dose, and the mean half-lives of irinotecan conversion to SN38 and SN38 elimination were 6.2 h (CV 171%) and 7.2 h (CV 48%). Irinotecan rapidly induced DNA damage, and DNA synthesis inhibition varied among patients and treatment cycles. All courses resulted in rapid cytoreduction, and two patients achieved complete remission. Topo-I activity did not predict response.

CONCLUSION

Irinotecan can be safely administered with Ara-C. This combination is active in refractory AML and warrants further study.

Oxaliplatin activity in head and neck cancer cell lines

Oxaliplatin (cis-[(1R,2R)-1,2-cyclohexanediamine-N,N'] [oxalato(2-)-O,O'] platinum; Eloxatin) is a third-generation platinum compound with a 1,2-diaminocyclohexane (DACH) carrier ligand, which has a wide spectrum of anticancer activity in vitro systems and has displayed preclinical and clinical activity in a wide variety of tumors. To investigate its in vitro activity against head and neck cancer, we exposed two head and neck cancer cell lines to the compound, created a variant resistant to cisplatin to study cross-resistance to the compound and analyzed the potential radiosensitizing effect of the drug. We report here that oxaliplatin was cytotoxic at similar doses to cisplatin in these cells. There was no cross-resistance to cisplatin, as demonstrated by different IC50 values in these cell lines and the sensitivity to oxaliplatin of the cisplatin-resistant cell line. There was an effective radiosensitizer effect of the compound in either cell line. Additional in vitro and in vivo experimentation is warranted in order to support the use of oxaliplatin as a radiosensitizer in head and neck cancer patients.