Solid Cancers Without Stage IV Disease
Most solid cancers do have a stage IV designation, but there are notable exceptions where the staging system does not include stage IV, particularly in certain head and neck cancers and some early-stage malignancies with unique staging systems.
Cancers That Lack Traditional Stage IV Classification
Testicular Cancer
- Testicular cancer is the most well-known solid tumor that does not use a stage IV designation in its standard staging system, which you've already identified 1.
- The staging system for testicular cancer uses stages I, II, and III, with stage III representing distant metastatic disease rather than stage IV 1.
Head and Neck Cancers - Important Nuances
- Head and neck cancers technically have stage IV disease, but it is subdivided into IVA (moderately advanced local/regional), IVB (very advanced local/regional), and IVC (distant metastatic) 1.
- The critical distinction is that stage IVA and IVB do not represent distant metastatic disease - they represent advanced locoregional disease without distant metastases 1.
- The AJCC 7th edition specifically changed terminology from "resectable" (T4a) and "unresectable" (T4b) to "moderately advanced" (T4a) and "very advanced" (T4b) to reflect that many stage IV head and neck cancers are potentially curable 1.
- Only stage IVC represents true distant metastatic disease in head and neck cancers, which is analogous to stage IV in other solid tumors 1.
Ovarian Cancer Staging Considerations
- Ovarian cancer uses the FIGO staging system which includes stage IV for distant metastases (parenchymal liver metastases or positive pleural effusion cytology) 1.
- However, stage III ovarian cancer includes peritoneal metastases beyond the pelvis and superficial liver metastases, which in many other cancers would be considered stage IV disease 1.
Key Clinical Implications
Stage IV Does Not Always Mean Incurable
- A designation of stage IV disease does not necessarily mean the disease is incurable, particularly in the absence of distant metastases 1.
- For melanoma, limited stage IV disease (resectable oligometastatic disease) can be treated with surgical resection followed by adjuvant therapy 1, 2.
- The National Comprehensive Cancer Network recommends that resection should be considered for resectable metastatic disease in stage IV patients when disease is limited or oligometastatic 2.
Common Pitfalls to Avoid
- Do not confuse staging systems across different cancer types - what constitutes "stage IV" varies significantly by primary tumor site 3.
- Do not assume all stage IV cancers are treated the same way - treatment depends on whether disease is limited/resectable versus disseminated/unresectable 1, 2.
- In head and neck cancers, stage IVA and IVB patients may have excellent outcomes with combined modality therapy despite the "stage IV" designation 1.
Bottom Line for Clinical Practice
Beyond testicular cancer, most solid tumors do have a stage IV designation, but the clinical significance and curability of "stage IV" varies dramatically by cancer type and extent of metastatic disease 1, 2. The key is understanding that stage IV in head and neck cancers often represents advanced locoregional disease rather than distant metastases, and that limited/oligometastatic stage IV disease in many solid tumors may be amenable to curative-intent treatment 1, 2.