Jorge Sabbaga

Operative Versus Nonoperative Treatment for Stage 0 Distal Rectal Cancer Following Chemoradiation Therapy Long-term Results

Objective:Report overall long-term results of stage 0 rectal cancer following neoadjuvant chemoradiation and compare long-term results between operative and nonoperative treatment. Methods:Two-hundred sixty-five patients with distal rectal adenocarcinoma considered resectable were treated by neoadjuvant chemoradiation (CRT) with 5-FU, Leucovorin and 5040 cGy. Patients with incomplete clinical response were referred to radical surgical resection. Patients with incomplete clinical response treated by surgery resulting in stage p0 were compared to patients with complete clinical response treated by nonoperative treatment. Statistical analysis was performed using χ2, Student t test and Kaplan-Meier curves. Results:Overall and disease-free 10-year survival rates were 97.7% and 84%. In 71 patients (26.8%) complete clinical response was observed following CRT (Observation group). Twenty-two patients (8.3%) showed incomplete clinical response and pT0N0M0 resected specimens (Resection group). There were no differences between patients demographics and tumors characteristics between groups. In the Resection group, 9 definitive colostomies and 7 diverting temporary ileostomies were performed. Mean follow-up was 57.3 months in Observation Group and 48 months in Resection Group. There were 3 systemic recurrences in each group and 2 endorectal recurrences in Observation Group. Two patients in the Resection group died of the disease. Five-year overall and disease-free survival rates were 88% and 83%, respectively, in Resection Group and 100% and 92% in Observation Group. Conclusions:Stage 0 rectal cancer disease is associated with excellent long-term results irrespective of treatment strategy. Surgical resection may not lead to improved outcome in this situation and may be associated with high rates of temporary or definitive stoma construction and unnecessary morbidity and mortality rates.

Increasing the rates of complete response to neoadjuvant chemoradiotherapy for distal rectal cancer: results of a prospective study using additional chemotherapy during the resting period.

OBJECTIVES: Addition of chemotherapy in the resting period between radiotherapy completion and response assessment during neoadjuvant treatment for distal rectal cancer could potentially increase rates of complete tumor regression. The purpose of this study was to evaluate toxicity rates and the impact of an extended neoadjuvant chemoradiation regimen on complete response rates. METHODS: Thirty-four consecutive patients with nonmetastatic distal rectal cancer were prospectively included. Patients were managed by 5,400 Gy of radiation and 5-fluorouracil/leucovorin-based chemotherapy given for three consecutive days every 21 days for six cycles (three cycles concomitant with radiotherapy). Tumor response assessment was performed at ten weeks from radiation completion. Patients with complete clinical response were strictly monitored and were not immediately operated on. Patients with incomplete clinical response were referred to surgery. RESULTS: Twenty-nine patients had completed 12 months of follow-up and were included in this preliminary analysis. Twenty-eight (97%) successfully completed treatment. Fifteen of 16 patients had Grade III toxicities that were skin-related (93%). Median follow-up was 23 months. Fourteen patients (48%) were considered as complete clinical responders sustained for at least 12 months (median, 24 months) after chemoradiation completion by clinical assessment alone. An additional five patients (17%) were considered as complete responders with ypT0 results after full-thickness local excision. Overall, the complete response rate was 65%. CONCLUSIONS: The addition of chemotherapy during the resting period after neoadjuvant chemoradiation is associated with acceptable toxicity and high tolerability rates. The considerably high rates of complete response in this preliminary series requires further follow-up, but they may provide valuable information for future prospective, randomized trials.

Bevacizumab: overview of the literature.

Inhibiting the angiogenic process is a clever method of cancer care. Over the last decade, some antiangiogenic compounds have been developed and approved for cancer treatment. Bevacizumab is a humanized monoclonal antibody that inhibits VEGF activity. When used in combination with chemotherapy, it has an important role for treating many types of advanced cancer, including colorectal cancer, renal cell carcinoma, non-small-cell lung cancer, breast cancer, ovarian cancer and glioblastoma multiforme. In this paper we review the basic science behind this molecule’s development, as well the major clinical trials in which bevacizumab was involved in oncology.

Comprehensive cancer-gene panels can be used to estimate mutational load and predict clinical benefit to PD-1 blockade in clinical practice

Cancer gene panels (CGPs) are already used in clinical practice to match tumors genetic profile with available targeted therapies. We aimed to determine if CGPs could also be applied to estimate tumor mutational load and predict clinical benefit to PD-1 and CTLA-4 checkpoint blockade therapy. Whole-exome sequencing (WES) mutation data obtained from melanoma and non-small cell lung cancer (NSCLC) patients published by Snyder et al. 2014 and Rizvi et al. 2015, respectively, were used to select nonsynonymous somatic mutations occurring in genes included in the Foundation Medicine Panel (FM-CGP) and in our own Institutional Panel (HSL-CGP). CGP-mutational load was calculated for each patient using both panels and was associated with clinical outcomes as defined and reported in the original articles. Higher CGP-mutational load was observed in NSCLC patients presenting durable clinical benefit (DCB) to PD-1 blockade (FM-CGP P=0.03, HSL-CGP P=0.01). We also observed that 69% of patients with high CGP-mutational load experienced DCB to PD-1 blockade, as compared to 20% of patients with low CGP-mutational load (FM-CGP and HSL-CGP P=0.01). Noteworthy, predictive accuracy of CGP-mutational load for DCB was not statistically different from that estimated by WES sequencing (P=0.73). Moreover, a high CGP-mutational load was significantly associated with progression-free survival (PFS) in patients treated with PD-1 blockade (FM-CGP P=0.005, HR 0.27, 95% IC 0.105 to 0.669; HSL-CGP P=0.008, HR 0.29, 95% IC 0.116 to 0.719). Similar associations between CGP-mutational load and clinical benefit to CTLA-4 blockade were not observed. In summary, our data reveals that CGPs can be used to estimate mutational load and to predict clinical benefit to PD-1 blockade, with similar accuracy to that reported using WES.

Primary prevention of colorectal cancer: Myth or reality?

Colorectal cancer incidence has been rising strongly in parallel with economic development. In the past few decades, much has been learned about the lifestyle, dietary and medication risk factors for this malignancy. With respect to lifestyle, compelling evidence indicates that prevention of weight gain and maintenance of a reasonable level of physical activity can positively influence in lowering the risk. Although there is controversy about the role of specific nutritional factors, consideration of dietary pattern as a whole appears useful for formulating recommendations. Though quite often recommended, the role for many supplements, including omega-3, vitamin D, folate, and vitamin B6, remains unsettled. Only calcium and vitamin D supplementation appear to add a modest benefit, particularly in those with a low daily intake. With regard to chemoprevention, medications such as aspirin and nonsteroidal anti-inflammatory drugs, and postmenopausal hormonal replacement for women might be associated with substantial reductions in colorectal cancer risk, though their utility is affected by their side effect profile. However, the role of agents such as statins, bisphosphonates and antioxidants have yet to be determined. Ultimately, primary prevention strategies focusing on modifying environmental, lifestyle risk factors, and chemopreventive drugs are options that have already been tested, and may impact on colon cancer incidence.

The use of personalized biomarkers and liquid biopsies to monitor treatment response and disease recurrence in locally advanced rectal cancer after neoadjuvant chemoradiation

Neoadjuvant chemoradiotherapy (nCRT) followed by surgery is the mainstay treatment for locally advanced rectal cancer. Variable degrees of tumor regression are observed after nCRT and alternative treatment strategies, including close surveillance without immediate surgery, have been investigated to spare patients with complete tumor regression from potentially adverse outcomes of radical surgery. However, clinical and radiological assessment of response does not allow accurate identification of patients with complete response. In addition, surveillance for recurrence is similarly important for these patients, as early detection of recurrence allows salvage resections and adjuvant interventions. We report the use of liquid biopsies and personalized biomarkers for monitoring treatment response to nCRT and detecting residual disease and recurrence in patients with rectal cancer. We sequenced the whole-genome of four rectal tumors to identify patient-specific chromosomal rearrangements that were used to monitor circulating tumor DNA (ctDNA) in liquid biopsies collected at diagnosis and during nCRT and follow-up. We compared ctDNA levels to clinical, radiological and pathological response to nCRT. Our results indicate that personalized biomarkers and liquid biopsies may not be sensitive for the detection of microscopic residual disease. However, it can be efficiently used to monitor treatment response to nCRT and detect disease recurrence, preceding increases in CEA levels and radiological diagnosis. Similar good results were observed when assessing tumor response to systemic therapy and disease progression. Our study supports the use of personalized biomarkers and liquid biopsies to tailor the management of rectal cancer patients, however, replication in a larger cohort is necessary to introduce this strategy into clinical practice.

Phase 2 Trial of Metformin Combined With 5-Fluorouracil in Patients With Refractory Metastatic Colorectal Cancer.

BACKGROUND Observational and preclinical studies have suggested that metformin has antitumor effects in solid tumors, including colorectal cancer (CRC). However, the effects of metformin in CRC have not been tested in clinical trials. PATIENTS AND METHODS This was a single-center, single-arm phase 2 clinical trial where histologically confirmed CRC patients with measurable and progressing metastatic disease previously treated with 5-fluorouracil (5-FU), irinotecan, oxaliplatin, and an anti-epidermal growth factor receptor (if the tumor was RAS wild type) were enrolled to receive metformin 850 mg orally continuously 2 times a day plus 5-FU 425 mg/m2 and leucovorin 50 mg intravenously weekly until disease progression, unacceptable toxicity, or withdrawal of consent. The primary end point was disease control rate at 8 weeks. RESULTS Among 50 patients included, 11 (22%) met the primary end point. The median progression-free survival was 1.8 months and the median overall survival 7.9 months. Analyzing only the 11 patients who experienced disease control at 8 weeks, their median progression-free survival was 5.6 months and their median overall survival was 16.2 months. There was a trend for prolonged median survival for obese patients (12.4 vs. 5.8 months) and those longer off 5-FU. The treatment was well tolerated; the main adverse effects were diarrhea, nausea, vomiting, and myelotoxicity. CONCLUSION Metformin and 5-FU showed an overall modest but intriguing activity in patients with refractory CRC in this phase 2 study. Some patients experienced long-term disease control. Further trials are needed to confirm these results, particularly in obese patients with CRC.

The effects of palliative chemotherapy in metastatic colorectal cancer patients with an ECOG performance status of 3 and 4.

BACKGROUND Although chemotherapy is standard for patients with mCRC and ECOG PS of 0/1, the real benefit for patients with ECOG PS > 2 remains uncertain, because they are generally excluded from clinical trials. Our objectives were to compare the survival and safety of ECOG PS 3/4 patients who were administered chemotherapy with those who received BSC only. PATIENTS AND METHODS We retrospectively analyzed all consecutive mCRC patients who started first-line chemotherapy at our institution in a 4-year period. A multivariable Cox regression model was used to adjust for prognostic factors and logistic regression, to identify predictive factors of Grade 3/4 toxicity. RESULTS From June 2008 to June 2012, 240 consecutive patients were included: 100 (41.7%) had an ECOG PS of 0/1, 75 (31.3%) ECOG PS of 2, and 65 (27%) ECOG PS of 3/4. Median survival for patients treated with chemotherapy was 18.4 months for patients with ECOG PS of 0/1, 10.8 months for those with ECOG PS of 2, and 6.8 months for patients with ECOG PS of 3/4. Among those with ECOG PS of 3/4, chemotherapy use led to a nonsignificant survival gain (median, 6.8 vs. 2.3 months for BSC; P = .13). Factors significantly associated with worse survival in an adjusted analysis were right-sided tumors (hazard ratio [HR], 2.97; P = .005) and ECOG PS status (ECOG PS 2 vs. 0/1; HR, 1.67; P = .025, and ECOG PS 3/4 vs. 0/1; HR, 2.67; P < .0001). The rate of Grade ≥ 3 toxicities during the first cycle did not differ significantly across ECOG groups; likely because 40% of ECOG PS 3/4 patients received upfront dose-reduced therapy. The rates of treatment-related hospitalization were similar across all ECOG groups. All deaths were disease-associated. CONCLUSION Our retrospective study suggests that chemotherapy might benefit selected mCRC patients with poor PS. With up-front dose reduction and close monitoring for toxicity, the risk of serious adverse events is minimized.

Integration of Anti-vascular Endothelial Growth Factor Therapies With Cytotoxic Chemotherapy in the Treatment of Colorectal Cancer

Colorectal cancer is one of the most prevalent malignancies worldwide, and its incidence continues to rise. The treatment for advanced colorectal cancer has significantly evolved in the last decade, with the addition of a number of new therapeutic agents; however, 5-fluorouracil remains at the core of most therapeutic approaches for this disease. Novel therapies targeting specific pathways have been developed for this disease, and the vascular endothelial growth factor ligand and receptor have been of particular interest. The blockade of what is considered the main angiogenic pathway is considered one of the main advances in cancer treatment. The aim of this article is to review the current status of the integration between anti-vascular endothelial growth factor therapies and cytotoxic chemotherapy, investigate what is known about development of resistance, and to explore new options of antiangiogenic treatments currently in late phases of development against colorectal cancer.

Acute Acalculous Cholecystitis in a Patient with Metastatic Renal Cell Carcinoma Treated with Sunitinib

A 55-year old man was treated with sunitinib 50 mg/day for 4 weeks on and 2 weeks off, as a first-line therapy for metastatic renal cell carcinoma. During the fourth week of the first cycle, he was admitted to the Emergency Department with abdominal pain and vomiting. Acute acalculous cholecystitis was diagnosed. Sunitnib-associated cholecystitis is a rare adverse event previously reported in few cases. The mechanism behind this complication is not fully understood, although vascular endothelial dysfunction may play a role. The use of this drug is expanding in clinical oncology, and physicians should be aware of this life-threating adverse event.