Risk of second primary colorectal cancer among colorectal cancer cases: a population-based analysis.

BACKGROUND: Patients with history of colorectal cancer (CRC) are at increased risk for developing a second primary colorectal cancer (SPCRC) as compared to the general population. However, the degree of risk is uncertain. Here, we attempt to quantify the risk, using data from the large population-based California Cancer Registry (CCR). MATERIALS AND METHODS: We analyzed the CCR data for cases with surgically-treated colon and rectal cancer diagnosed during the period 1990-2005 and followed through up to January 2008. We excluded those patients diagnosed with metastatic disease and those in whom SPCRC was diagnosed within 6 months of the diagnosis of the primary CRC. Standardized incidence ratios (SIR) with 95% confidence intervals (CI) were calculated to evaluate risk as compared to the underlying population after taking into account age, sex, ethnicity, and time at risk. RESULTS: The study cohort consisted of 69809 cases with colon cancer and 34448 with rectal cancer. Among these patients there were 1443 cases of SPCRCs. The SIR for developing SPCRC was higher in colon cancer survivors (SIR=1.4; 95% CI: 1.3 to 1.5) as compared to the underlying population. The incidence of SPCRC was also higher in females (SIR=1.5; 95% CI: 1.3 to 1.6) and Hispanics (SIR=2.0; 95% CI: 1.7 to 2.4) with primary colon cancer. The SIR for developing an SPCRC was higher only among those whose initial tumor was located in the descending colon (SIR=1.6; 95% CI: 1.3 to 2.0) and proximal colon (SIR=1.4; 95% CI: 1.3 to 1.6). CONCLUSIONS: Our results confirm that CRC patients, especially females and Hispanics, are at a higher risk of developing SPCRC than the general population. Differential SPCRC risk by colorectal tumor subsite is dependent on gender and ethnicity, underscoring the heterogeneous nature of CRC.

Timing of radiation therapy, lymph node retrieval, and survival in rectal cancer.

BACKGROUND: Lymph node retrieval is an independent prognostic factor for survival in rectal cancer. Preoperative radiotherapy has been shown to impact the number of lymph nodes retrieved. OBJECTIVE: This study aimed to analyze colorectal cancer-specific mortality and overall mortality associated with the number of lymph nodes retrieved in relation to use and timing of radiotherapy. DESIGN: This study was designed as a retrospective analysis. SETTINGS: Analysis of the California Cancer Registry was conducted. PATIENTS: Patients with rectal cancer from 1994 to 2006 with a follow-up until January 2008 were included. MAIN OUTCOME MEASURES: The number of lymph nodes (1-3, 4-6, 7-11, ≥ 12) stratified by stage (I, II, and III) was analyzed based on radiotherapy status (no radiotherapy, preoperative radiotherapy, and postoperative radiotherapy). Multivariate colorectal cancer-specific survival and overall mortality analyses were performed using Cox proportional-hazard ratios. RESULTS: A total of 17,670 incident cases of stage I, II, and III rectal cancer were identified. The number of lymph nodes retrieved in cases receiving preoperative radiotherapy was lower than others. In stage II cases receiving preoperative radiotherapy, retrieval of 7 to 11 lymph nodes (compared with 0 lymph nodes retrieved as a reference) reached the nadir of colorectal cancer-specific mortality benefit (HR = 0.39, 95% CI, 0.28-0.56) and overall mortality (HR = 0.62, 95% CI, 0.48-0.80). In stage II cases with no radiotherapy or postoperative radiotherapy, retrieval of ≥ 12 lymph nodes remained the strongest prognosticator of colorectal cancer-specific mortality (HR = 0.34, 95% CI, 0.25-0.46; HR = 0.36, 95% CI, 0.24-0.53 respectively). LIMITATIONS: : The California Cancer Registry does not include radiation dose and duration, chemotherapy type and dosage, margin status and surgeon characteristics, and stated reasons for lower number of lymph nodes retrieved or patient-related factors. In addition, no central pathology laboratory was used. CONCLUSIONS: In stage II rectal cancer cases receiving preoperative radiotherapy vs either postoperative or no radiotherapy, a lower threshold of lymph node retrieval may be sufficient to evaluate prognosis and to guide further therapy.

Need for a new treatment strategy: leptomeningeal carcinomatosis from gastric cancer.

Leptomeningeal carcinomatosis (LMC) is an extremely rare manifestation of gastric cancer. The treatment options are very limited for LMC; despite standard treatment with intrathecal chemotherapy, the prognosis is grim and the median overall survival is 3-4 months. Here we report on a patient with LMC from metastatic gastric cancer who was treated with a novel approach of high-dose systemic irinotecan, comparable with the dose utilized in treating primary brain tumors such as gliomas. Our patient not only had an excellent tumor response to this novel approach, but also had a prolonged overall survival of 13 months, which is unusual for LMC from gastric cancer.