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Cancer Cluster Investigations in Delaware


New Castle County

2017 Investigations

  1. Requested: September 2017, by an individual
    Geographic Area: Wilmington
    Cancer Type: General cancer cases

    What was done: All-site cancer incidence rates for the census tract with the requestor’s address and the adjacent census tracts were calculated and compared to the all-site cancer incidence rate in Delaware. None of the census tracts has significantly higher all-site cancer incidence rates compared to Delaware for 6 time periods over the last 10 years. A summary report was provided to the requestor.

    Outcome: No cluster detected, no further action indicated.

2014 Investigations

  1. Requested: April, 2014, by an individual
    Geographic Area: Newark, Delaware
    Cancer Type: all cancers

    What was done: Aggregated all census tracts within boundaries of Newark, Delaware. Calculated 2006-2010 incidence rate for all cancers combined and determined that the overall cancer incidence rate was not significantly different compared to the U.S., Delaware or New Castle County. In addition, incidence rates for 23 cancer types did not differ significantly from the Delaware incidence rates. A summary report of the investigation was provided to the requestor.

    Outcome: No cluster detected, no further action indicated.

2010 Investigations

  1. Requested: January 2010, by an individual
    Geographic Area: New Castle County and Statewide
    Cancer Type: Childhood cancer (all-site)

    What was done: Calculated 2002-2006 incidence and mortality rates for all-site cancers diagnosed among Delaware youth ages 19 and younger. While childhood cancer incidence rates were calculated at the county-level, childhood cancer mortality rates could not be broken down by county due to low case numbers and patient confidentiality concerns. Childhood cancer incidence rates for New Castle and Sussex Counties were not significantly different from those at the state and national levels. The Kent County childhood cancer incidence rate was not significantly elevated compared to the state rate; however, the Kent County childhood cancer incidence rate was significantly elevated compared to the U.S. rate. Delaware’s childhood cancer mortality rate was not significantly elevated compared to the U.S. childhood cancer mortality rate. No major differences between Delaware and the U.S. were detected in the proportion of childhood cancer cases by International Classification of Childhood Cancer (ICCC) subgroup. The annual number of childhood cancer cases diagnosed in Delaware has remained relatively stable since 1980. A summary report was provided to the requestor.

    Outcome: DPH will continue monitoring childhood cancer incidence and mortality rates among Delaware youth and assume position of watchful waiting for childhood cancer incidence trends in Kent County.

2009 Investigations

  1. Requested: August 2009, by an individual
    Geographic Area: Census tract 149.05 (area bordered by Christiana Road, S. DuPont and Pulaski Highways, and Appleby Road; inclusive of the Ashton Condos neighborhood)
    Cancer Type: All types (all-site), with an emphasis on brain/CNS cancer

    What was done: Calculated 2001-2005 incidence rates for all-site cancer for census tract 149.05; determined that the combined male and female all-site cancer incidence rate for census tract 149.05 was not significantly elevated compared to New Castle County, Delaware, or the U.S. When all-site cancer incidence rates for census tract 149.05 were broken down by sex, the male all-site cancer incidence rate for census tract 149.05 was significantly elevated compared to the rate for Delaware males. The all-site cancer incidence rate for females in census tract 149.05 was not significantly different from the rate for Delaware females. To investigate which site-specific cancers were responsible for the elevated male all-site incidence rate in census tract 149.05, incidence rates were calculated for the 24 most commonly diagnosed cancer types. Among males in census tract 149.05, two cancer types were significantly higher than the state rates for the 2001-05 period: colorectal cancer and esophageal cancer. While male colorectal and esophageal cancer incidence rates were elevated in census tract 149.05, age-at-diagnosis trends were normal among this population. A summary report of the investigation was provided to the requestor.

    Outcome: DPH will continue monitoring male colorectal and esophageal cancer trends in census tract 149.05.

  2. Requested: August 2009, by an individual
    Geographic Area: Census tract 104.00 (Claymont area)
    Cancer Type: Brain cancer

    What was done: Calculated 2000-2004 and 2001-2005 incidence rates for brain/CNS cancer for census tract 104.00; determined that the combined male and female incidence rate was not significantly different compared to New Castle County, Delaware, and the U.S. In addition, sex specific (males only and females only) brain/CNS incidence rates did not significantly differ at the census tract level compared to other geographic levels. A summary report of the investigation was provided to the requestor.

    Outcome: No cluster detected, no further action indicated.

  3. Requested: July 2009, by an individual
    Geographic Area: Census tract 103.00 (Claymont area) near Evraz Steel
    Cancer Type: All types (all-site) with special concern re: cancers in women

    What was done: Calculated 2001-2005 incidence rates for all-site and various other cancer types for census tract 103.00; determined that the combined male and female all-site cancer incidence rate was not significantly different compared to New Castle County, Delaware, and the U.S. When examined for females only, the all-site and site-specific incidence rates did not significantly differ at the census tract level compared to other geographic levels. The most commonly diagnosed cancers in the area did not support a link to environmental causation. A summary report of the investigation was provided to the requestor, along with information about types of cancers associated with exposure to pollutants from the steel industry.

    Outcome: No cluster detected, no further action indicated.

  4. Requested: June 2009, by an individual
    Geographic Area: Census tract 112.05 (area bordered by Naamans, Foulk, and Grubb Roads; inclusive of Brandywood Park, Brandywood Beacon Hill Park, and the surrounding residential areas)
    Cancer Type: All types (all-site)

    What was done: Calculated 2001-2005 incidence rates for all-site and various other cancer types for census tract 112.05; determined that the combined male and female all-site cancer incidence rate for census tract 112.05 was significantly elevated compared to New Castle County, Delaware, and the U.S. When all-site cancer incidence rates for census tract 112.05 were calculated separately for males and females, the female all-site cancer rate for census tract 112.05 was significantly elevated compared to the rate for Delaware females. The all-site cancer incidence rate for males in census tract 112.05 was not significantly elevated compared to the rate for Delaware males. To investigate which site-specific cancers were responsible for the elevated female all-site incidence rate in census tract 112.05, incidence rates were calculated for 24 individual cancer types. Among females in census tract 112.05, only melanoma was significantly higher than the state rate for the 2001-05 period. A summary report of the investigation was provided to the requestor, along with information about melanoma risk factors and prevention.

    Outcome: DPH will continue monitoring female melanoma trends in census tract 112.05.

2008 Investigations

  1. Requested: September 2008, by an individual
    Geographic Area: Zip Code 19810 (inclusive of the Dartmouth Woods residential area)
    Cancer Type: All types (all-site), with an emphasis on thyroid cancer

    What was done: Calculated 2000-2004 incidence rates for all-site and various other cancer types for zip code 19810; determined that the combined male and female all-site rate for Zip Code 19810 was not significantly elevated compared the rates for New Castle County, Delaware, or the U.S. Incidence rates were calculated for the 24 most commonly diagnosed cancer types. For 2000-2004, the melanoma incidence rate for Zip Code 19810 was significantly elevated compared to Delaware’s melanoma incidence rate. The 2000-2004 thyroid cancer incidence rate for zip code 19810 was not significantly greater than the thyroid cancer incidence rates for New Castle County or Delaware. DPH contacted the Office of Drinking Water (ODW) and a private laboratory in Wilmington to inquire about private well water testing options; based on requestor’s address, DPH determined that the requestor receives public water via United Water Delaware (UWD). A summary report was provided to requestor along with information about melanoma risk factors and information for accessing UWD water quality reports.

    Outcome: DPH will continue to monitor melanoma incidence rates in Zip Code 19810.

  2. Requested: July 2008, by an individual
    Geographic Area: Smyrna, census tract 169.02 (area east of Rt. 13, near Black Diamond and Eagles Nest Roads)
    Cancer Type: All types (all-site)

    What was done: Calculated 2000-2004 incidence rates for all-site and various other cancer types for census tract 169.02; identified a significantly elevated all-site incidence rate for census tract 169.02; determined that the elevated all-site rate was attributable to a significantly elevated kidney cancer rate in the area under investigation; verified that kidney cancer age of diagnosis patterns were normal within census tract 169.02; contacted the Office of Drinking Water (ODW) and a private laboratory in Wilmington to inquire about private well water testing options; contacted the Department of Natural Resources and Environmental Control (DNREC) to determine if any point source water contamination had occurred in the immediate area of where the requester resides (DNREC was not aware of any water contamination occurrences in that immediate area); provided summary of investigation to requester stating all-site and kidney cancer were elevated in the area under investigation; summary report included information on kidney cancer risk factors and private well water testing information.

    Outcome: DPH will assume position of watchful waiting for kidney cancer in census tract 169.02.

  3. Requested: February 2008, by an individual
    Geographic Area: Wilmington, Zip Codes 19804 and 19808
    Cancer Type: Female Breast

    What was done : Obtained information from requester regarding female breast cancer cases diagnosed in areas in which she has lived; calculated 2000-2004 female breast cancer incidence rates by race for Zip Codes 19804 and 19808; compared Zip Code rates to county, state and national rates; confirmed that female breast cancer cases were diagnosed in expected age groups (=>35 years of age); determined the majority (67%) of female breast cancers in these two Zip Codes were being diagnosed at the early stage; provided summary of investigation to requester.

    Outcome : No female breast cancer cluster confirmed.

2007 Investigations

  1. Requested: November 2007, by an individual
    Geographic Area: Wilmington area, Zip Code 19810
    Cancer Type: Female breast

    What was done: Obtained information from requester re: acquaintances diagnosed with female breast cancer; reviewed Registry abstracts of supplied cases; calculated 2000-2004 incidence rates for all-site and various other cancer types for Zip Code 19810 and census tract 113.00; determined that female breast cancer rates in this Zip Code and census tract were not significantly elevated compared to the state or nation; identified seven cancers in census tract 113.00 with significantly lower rates compared to the state as a whole; determined that melanoma rates were significantly elevated for Zip Code 19810 compared to the state as a whole; provided summary of investigation to requester stating that the melanoma rate was elevated in Zip Code 19810; summary report included information on melanoma risk factors and skin cancer prevention strategies.

    Outcome: No female breast cancer cluster confirmed; DPH will assume position of watchful waiting for melanoma rates in Zip Code 19810.

  2. Requested: October 2007, by an individual
    Geographic Area: Newark, census tract 144.02 (area near Elkton Rd., Chrysler Ave., Amstel Ave. and Orchard Rd.)
    Cancer Type: all types (all-site)

    What was done: Obtained information from requester and other informants (supplied by requester) re: various cancer types; reviewed Registry abstracts of supplied cases; calculated 2000-2004 incidence rates by sex and race for all-site and various other cancer types by Zip Code (19711) and census tract (144.02); compared area rates to county, state and national rates; reviewed trends in all cancer cases diagnosed in Zip Code since 1980; confirmed no cancers were being diagnosed in unexpected age groups and no ‘rare’ cancers occurred with unexpected frequency; provided summary of investigation to requester stating that investigation results could not correlate area cancer rates with proximity to Chrysler plant.

    Outcome: No cluster confirmed.

  3. Requested: August 2007, by an individual
    Geographic Area: Wilmington, Zip Code 19803
    Cancer Type: Brain/CNS (Central Nervous System)

    What was done: Obtained information from requester regarding acquaintances diagnosed with brain/CNS cancer; reviewed Registry abstracts of supplied cases; calculated 2000-2004 incidence rates for all-site and various other cancer types for Zip Code 19803; determined that brain/CNS cancer rates in this Zip Code were not significantly elevated compared to the state or nation; verified that brain/CNS cancer age of diagnosis patterns were normal within Zip Code 19803; provided summary of investigation to requester stating that the brain/CNS cancer rate in her Zip Code was not elevated.

    Outcome: No brain/CNS cancer cluster confirmed.

2006 Investigations

  1. Requested: November 2006, by an individual
    Geographic Area: Middletown, Townsend, and portions of Smyrna; Kent County
    Cancer Type: Pancreatic cancer

    What was done: Obtained details from requester; reviewed Registry abstracts of 11 of 12 cases of interest; four of 12 cases revealed a primary cancer site other than the pancreas; reviewed state and Zip Code-specific statistics for the Zip Codes represented by the seven cases of primary pancreatic cancer and for other Zip Codes of similarly-sized populations; confirmed that number of cases was consistent with expected number per Zip Code populations and per age groups represented.

    Outcome: No cluster confirmed.

2005 Investigations

  1. Requested: November 2005, by an individual
    Geographic Area: Bear; Zip Code 19701 (area near Country Side Lane)
    Cancer Type: Primarily female breast

    What was done: Obtained details from requester and other informants regarding breast cancer cases diagnosed in the area in which requester resided; reviewed Registry abstracts of cases; reviewed state and county breast cancer statistics for age ranges of cases of concern (=>35 years of age); confirmed that cases likely reflected breast cancer's known frequency or occurrence, increased risk associated with age (two cases occurred in women age 55 or older) and family history of breast cancer (three of five cases occurred in one family).

    Outcome: No cluster confirmed.


Kent County


2009 Investigations

  1. Requested: October 2009, by an individual
    Geographic Area: Kent County and Statewide
    Cancer Type: Hodgkin Lymphoma (HL)

    What was done: Calculated 2000-2004 and 2001-2005 HL rates for Delaware and its three counties. None of the HL incidence rates at the state- and county-level were significantly elevated compared to the U.S. rate for either period. Statewide, HL cases are distributed fairly equally between both sexes. From 2001-2005, Delaware males and females accounted for 51.1% and 48.9% of cases, respectively. In Delaware, like the rest of the nation, HL is most common among Caucasians. From 2001-2005, 77.4% of HL cases were diagnosed among Caucasian Delawareans. A summary report was provided to the requestor; the report also included HL risk factor and survival rate information.

    Outcome: No HL cluster confirmed.

2008 Investigations

  1. Requested: November 2008, by an individual
    Geographic Area: Dover area, Zip Code 19904
    Cancer Type: All types (all-site), with an emphasis on Ewing sarcoma (ES)

    What was done: Calculated 2000-2004 incidence rates for all-site and various other cancer types for Zip Code 19904; determined that the all-site cancer incidence rate for Zip Code 19904 was significantly lower compared to the rates for Kent County, Delaware, and the U.S. Compared to Delaware as a whole, Zip Code 19904 was not significantly elevated for any of the 24 most commonly diagnosed cancer types. In terms of ES, diagnosis trends in Delaware mirror trends seen at the national level. Nationwide, approximately two-thirds of ES cases are diagnosed among youth ages 10-20. In Delaware, since 1980, just over two-thirds of ES cases have been diagnosed among young people in this age group. Also consistent with national trends, the majority (84%) of ES cases diagnosed in Delaware since 1980 were diagnosed among white, non-Hispanic individuals. Finally, Delaware’s ES trends mirror national trends with respect to patient sex. Nationwide, males are slightly more likely than females to develop ES; in Delaware, since 1980, roughly 72% of Ewing sarcoma cases have been diagnosed among males.

    Outcome: No cancer cluster confirmed.


Sussex County

2016 Investigations

  1. Requested: December 2016, by an individual
    Geographic Area: Heritage Village in Seaford, DE
    Cancer Type: All cancers

    What was done: Cancer incidence rates for all census tracts within the boundaries of Seaford, DE were calculated and compared to overall Delaware cancer incidence rates. Historical census tract data was compared over 5 year periods and only the 2008-2012 incidence rate for census tract 504.05 was significantly higher than the Delaware incidence rate. There were 23 site specific incidence rates calculated and compared to the Delaware site specific incidence rates. While there were some sites that had significantly higher incidence rates only one individual matched the site specific cancer for 2008-2012. A summary report was provided to the requestor.

    Outcome: No cluster detected, no further action indicated.

2009 Investigations

  1. Requested: November 2009, by an individual
    Geographic Area: Indian River area (operationally defined as zip codes 19939, 19945, 19947, 19966, 19970, and 19975)
    Cancer Type: All types (all-site), with an emphasis on female breast cancer

    What was done: Calculated 2000-2004, 2001-2005, and 2002-2006 incidence rates for all-site and various other cancer types for the Indian River area. The 2001-05 and 2002-06 all-site cancer incidence rates for the Indian River area were significantly elevated compared to Delaware as a whole. However, when rates for the 24 most commonly diagnosed cancer types were calculated separately for males and females, the data confirmed that significantly elevated bladder and lung cancer rates among Indian River males were responsible for the elevated all-site cancer rates. With the exception of bladder and lung cancer, no other cancer types were significantly elevated among Indian River males. None of the 24 cancer types were significantly elevated among Indian River females. In terms of female breast cancer, Indian River females are no more likely to develop or be diagnosed with the disease at an earlier age than would normally be expected given state and national statistics. A summary report of the investigation was provided to the requestor.

    Outcome: In 2009, DPH completed the Indian River Community-Level Survey (IRCLS), a retrospective study designed to investigate lung cancer risk factors among Indian River residents. DPH will use findings from the IRCLS, as well as this cancer cluster investigation, to continue monitoring bladder and lung cancer incidence rates among Indian River males.

  2. Requested: October 2009, by an individual
    Geographic Area: Census tract 502.00 (area bordered on the north by Staytonville, Fleatown, Hollytree, Ponder, and Jefferson Roads; on the east by Cedar Creek, Isaacs, and Gravel Hill Roads; on the south by Neptune, Sandhill, and Redden Roads; and on the west by Union Church Road).
    Cancer Type: All types (all-site)

    What was done: Calculated 2001-2005 incidence rates for all-site and various other cancer types for census tract 502.00; determined that the combined male and female all-site cancer incidence rate for census tract 502.00 was not significantly elevated compared to Sussex County, Delaware, or the U.S. The data confirmed that neither males nor females in census tract 502.00 had significantly incidence rates for any of the 24 most commonly diagnosed cancer types.

    Outcome: No cancer cluster confirmed.

2008 Investigations

  1. Requested: May 2008, by an individual
    Geographic Area: Lewes area; Zip Code 19958
    Cancer Type: Lung

    What was done: Calculated 2000-2004 incidence rates for all-site and various other cancer types for Zip Code 19958; determined that the lung cancer incidence rate for Zip Code 19958 was not elevated compared to the state or the nation; identified a significantly elevated all-site incidence rate for Zip Code 19958; determined that the elevated all-site rate was attributable to significantly elevated bladder cancer and non-Hodgkin lymphoma (NHL) rates in the area under investigation; verified that bladder cancer and NHL age of diagnosis patterns were normal within Zip Code 19958; provided summary of investigation to requester stating that bladder cancer and NHL rates are elevated for Zip Code 19958; summary report included information on risk factors for these two cancer types.

    Outcome: No lung cancer cluster confirmed; DPH will assume position of watchful waiting for bladder cancer and NHL in Zip Code 19958.

  2. Requested: January 2008, by an individual
    Geographic Area: Millsboro/Long Neck; census tract 507.02 (area near Banks Road and John J Williams Highway)
    Cancer Type: All types (all-site)

    What was done: Obtained information from requester regarding various cancer types; reviewed Registry abstracts of supplied cases; calculated 2000-2004 and 2001-2005 incidence rates for all-site and various other cancer types for census tract 507.02; compared census tract rates to county, state and national rates; confirmed no cancers were diagnosed in unexpected age groups and no ‘rare’ cancers occurred with unexpected frequency; reviewed well water test results from two private wells and from one of Delaware’s Department of Agriculture test wells nearby; provided summary of investigation to requester stating that only lung cancer was elevated for the area (currently being addressed by Indian River Project) and that well water testing did not indicate link between well water contamination and cancer rates for the area.

    Outcome: No cancer cluster confirmed.

2007 Investigations

  1. Requested: December 2007, by an individual
    Geographic Area: Millville, Zip Codes 19967 and 19970
    Cancer Type: All types (all-site)

    What was done: Obtained information from requester regarding various cancer types; reviewed Registry abstracts of supplied cases; calculated 2000-2004 incidence rates by sex for all-site and various other cancer types for Zip Codes 19967 and 19970 as one combined area; compared area rates to county, state and national rates; confirmed no cancers were diagnosed in unexpected age groups and no ‘rare’ cancers occurred with unexpected frequency; provided summary of investigation to requester stating that all-site incidence rate was elevated for the area but no individual cancer types were elevated for the area.

    Outcome: No cluster confirmed; DPH will assume position of watchful waiting for this area.

2006 Investigations

  1. Requested: December 2006, by a citizen action group
    Geographic Area: Zip Codes 19939, 19945, 19947, 19966, 19970, and 19975
    Cancer Type: All types (all-site), with an emphasis on lung cancer

    What was done: Data from the Registry were reviewed; 2000-2004 incidence rates were calculated for all-site and lung cancer in the six zip-code area; results revealed elevated all-site and lung cancer rates in the area under investigation. A full report on the Indian River Cancer Cluster Investigation is available on this website. A follow-up study — the Indian River Community Level Survey is being conducted to determine if other confounding factors, such as age, immigration, or tobacco use, might account for the suspected cluster.

    Outcome: All-site and lung cancer rates were elevated in the six-Zip Code area. An in-depth investigation into lung cancer rates across Sussex County is currently underway. Results from the in-depth investigation are expected in early 2009.

2005 Investigations

  1. Requested: September 2005, by an individual
    Geographic Area: Area of Sussex Pines Road, Zoar Road, and Gravel Hill Road
    Cancer Type: Primarily Brain/CNS (Central Nervous System)

    What was done: Obtained details from requester regarding cancer cases diagnosed in residential area; reviewed Registry abstracts; two of four cases revealed a primary cancer site other than what the requester had reported; reviewed state and county cancer statistics for brain/CNS cancer; confirmed cases of brain/CNS cancer occurred in expected age groups (=>45 years of age). Provided summary of investigation and background information on brain/CNS cancer to requester.

    Outcome: No cluster confirmed.

2004 Investigations

  1. Requested: June 2004, by an individual
    Geographic Area: Ellendale
    Cancer Type: All types (all-site)

    What was done: Data from the Registry and Vital Statistics were reviewed; no common histological site was identified among cancer cases; based on investigation results, investigator concluded that cancer cases could not be linked to the community concern about possible water contamination from gas stations and nearby dumps.

    Outcome: No cluster confirmed.


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