The September 2021 Update includes changes that apply to cases diagnosed January 1, 2022 and after. The editors recommend that until these changes are implemented, registrars continue using the current Solid Tumor Rules (PDF, 7.0 MB), updated December 2020, for cases diagnosed from January 1, 2018 through 12/31/2021.

Use the Solid Tumor Rules to determine the number of primaries to abstract and the histology to code. The Solid Tumor Rules and General Instructions replace the 2007 Multiple Primary & Histology (MP/H) Rules for the following sites:

  • Breast
  • Colon (includes rectosigmoid and rectum for cases diagnosed 1/1/2018 forward)
  • Head & Neck
  • Kidney
  • Lung
  • Malignant CNS and Peripheral Nerves
  • Non-malignant CNS
  • Urinary Sites

Cutaneous Melanoma Rules

Use the Cutaneous Melanoma Solid Tumor Rules to determine the number of primaries to abstract and the histology to code for cases diagnosed 1/1/2021 and forward. The Solid Tumor Cutaneous Melanoma Rules and General Instructions replace the 2007 Multiple Primary & Histology (MP/H) Rules beginning 1/1/2021.

Revision status for remaining 2007 Multiple Primary and Histology rules:

We are currently working on revisions to the Other Sites MP/H module. Release date has not yet been determined. The 2007 MP/H and 2007 General Instructions are to be used, with a few exceptions, for cases for the following site groups until instructed to do otherwise:

Other Sites:

The following primary sites are excluded for 1/1/2018 forward:

  • Rectosigmoid and rectum which are included in Colon Solid Tumor Rules
  • Peripheral nerves which are included in the Malignant CNS Solid Tumor Rules

We have identified the need to separate select sites into individual modules. These site-specific rules may be individual sections within the Other sites rules, or free-standing modules. The following sites have been determined to need additional rules: GYN, GI (excluding colorectal), Thyroid, Soft tissue/bone, and Male genital.

Download the Solid Tumor Modules

All sections were updated on September 17, 2021.

Use the 2007 General Instructions, Other Sites for cases diagnosed 2007-2022.

Use the 2007 General Instructions, Cutaneous Melanoma sections for cutaneous melanoma cases diagnosed 2007-2020.

Revision History

The change log contains updates made in September 2021. Please see the Revision Archive for earlier changes.

Histology Coding Clarifications

On occasion, data collection requirements of AJCC and NCI SEER have resulted in conflicting cancer coding instructions for cancer registrars. For more information and specific instructions about reviewing cases already coded, please visit the Histology Coding Clarifications page.

Suggested Citation

Dickie L., Johnson, CH., Adams, S., Negoita, S. (September 2021). Solid Tumor Rules. National Cancer Institute, Rockville, MD 20850.