The researchers are doing this study to find out more about what may lead to the loss of tooth enamel (the thin outer covering of the tooth) and how often it happens in people with esophagogastric cancer, colorectal cancer, pancreatic cancer, breast cancer, head and neck cancer, or non-small cell lung cancer, or a healthy volunteer.

Inclusion Criteria:

• Subject is willing and able to provide written informed consent.
• Patients with a history of esophagogastric, HNSCC, PDAC, CRC, or NSCLC or healthy controls
• Patients must be able to fully comprehend and complete the survey and be willing to have pictures taken of their teeth with a camera or intra-oral camera.
• Patients must be able to understand English language or have access to adequate translation services.
• Age ≥ 18 years old.

Exclusion Criteria:

• Subjects without evaluable molars or with significant molar dental work precluding dentists from assessing enamel status, Note: evaluable is defined as having bilateral assessable mandibular molars, or erosions present in the remaining assessable quadrants.
• For healthy controls only, patients cannot have a non-skin cancer history nor presenting for a procedure evaluating reflux symptoms.

Memorial Sloan Kettering Cancer Center supports the international committee of medical journal editors (ICMJE) and the ethical obligation of responsible sharing of data from clinical trials. The protocol summary, a statistical summary, and informed consent form will be made available on clinicaltrials.gov when required as a condition of Federal awards, other agreements supporting the research and/or as otherwise required. Requests for deidentified individual participant data can be made beginning 12 months after publication and for up to 36 months post publication. Deidentified individual participant data reported in the manuscript will be shared under the terms of a Data Use Agreement and may only be used for approved proposals. Requests may be made to: crdatashare@mskcc.org