Rhabdomyosarcoma: Staging, Grading, Risk Stratification, Treatment

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Rhabdomyosarcoma

Sarcoma Committee of the Children’s Oncology Group prescribed system is mostly used for assigning a stage, clinical group, and risk group to Rhabdomyosarcoma.

What is the TNM Staging of Rhabdomyosarcoma?

TNM system is used for assigning a stage to RMS. “T” stands for “Tumor Size” and invasiveness, “N” for “Lymph Nodes”, and “M” for “Metastasis”. Numbers and/or letters after T (1, 1a, 1b, 2, 2a, and 2b), N (0 and 1), and M (0 and 1) provide more details about each of these factors.

Additionally, the sites of RMS are grouped into favorable (F) and unfavorable (UF) based on the prognosis of disease at different sites. Favorable sites include Orbit (eyeball); head and neck area except the para-meningeal area (nasal passages and nearby sinuses, middle ear, and the uppermost part of the pharynx); genitourinary tract except the kidney, bladder, and prostate; and the biliary duct. All other sites are considered as unfavorable.

T STAGING

T1 – Confined to the anatomic site of origin

a – </= 5 cm in maximum diameter

b – > 5 cm in maximum diameter

T2 – Extension and/or fixity to surrounding structures

a – </= 5 cm in maximum diameter

b – > 5 cm in maximum diameter

N STAGING

N0 – No spread of the tumor to regional lymph nodes

N1 – Regional lymph nodes involved by tumor

M STAGING

M0 – No spread of the tumor to distant sites

M1 – Tumor spread to non-regional nodes or distant sites

What are the 4 Stages of Rhabdomyosarcoma?

Once T, N, and M categories and the site of a tumor are determined through different diagnostic techniques, this information is combined to assign an overall stage (from 0 to IV) to the disease.

Stage I 

F; Any T, Any N, M0

The primary tumor is present at a favorable site, which may be of any size. It may or may not have invaded into a nearby tissue and/or spread to nearby lymph nodes, but has not spread to distant body parts.

Stage II 

UF; T1a-2a N0 M0

The primary tumor is present at an unfavorable site, which is </=5 cm in size. It may or may not have invaded into a nearby tissue, but has not spread to nearby lymph nodes. No spread to distant body parts.

Stage III

UF; T1a-2a N1 M0

The primary tumor is present at an unfavorable site, which is </=5 cm in size. It may or may not have invaded into a nearby tissue, but has spread to nearby lymph nodes. No spread to distant body parts.

UF; T1b-2b N0 M0

The primary tumor is present at an unfavorable site, which is >5 cm in size. It may or may not have invaded into a nearby tissue and/or spread to nearby lymph nodes. No spread to distant body parts.

Stage IV 

Any site; Any T Any N M1

The primary tumor is present at a favorable or an unfavorable site. It may be of any size. It may or may not have invaded into a nearby tissue and/or spread to nearby lymph nodes. It has spread to distant body parts, like the lungs, liver, bones, or bone marrow.

What is Clinical Stage Grouping of Rhabdomyosarcoma?

Based on the extent of the disease and the extent of primary surgical/biopsy excision, RMS is assigned a clinical group as described in the following table:

Group I

A localized tumor that has been completely removed by surgery/biopsy with negative/clear margins and no sign of lymph node involvement (no cancer left behind).

Group II

A localized tumor that has been completely removed by surgery/biopsy with a microscopic positive margin and/or sign of lymph node involvement (minor cancer left behind).

Group III

A localized tumor that was not completely removed by surgery/biopsy with a positive margin. Sign of lymph node involvement may be present but no sign of disease spread to distant body parts.

Group IV

The diagnosis has revealed the spread of disease to distant body parts or presence of cancer cells in the cerebral spinal fluid, pleural, or peritoneal fluids.

How is Risk Stratification of Rhabdomyosarcoma done?

Based on the overall stage, clinical group, and type of RMS (embryonal or alveolar), a risk group is assigned to the disease. Risk group helps in selecting appropriate treatment for the disease. 

Low risk

Embryonal RMS; TNM stage 1; and Clinical groups I, II, or III, OR
Embryonal RMS; TNM stage 2 or 3; and Clinical groups I or II

Intermediate risk

Embryonal RMS; TNM stage 2 or 3; and Clinical group III OR
Alveolar RMS; TNM stage 1, 2, or 3; and Clinical groups I, II, or III

High risk

Embryonal/Alveolar RMS; TNM stage 4; and Clinical group IV

What is the Survival according to Stage of Rhabdomyosarcoma?

Survival rates give you an idea of percentage of people that are alive 5 years after being diagnosed with rhabdomyosarcoma. 

It is calculated based on whether the disease is Low Risk, Intermediate Risk or High Risk.

Low Risk

  • 5 year survival 70-90%
  • It may vary with tumor location, stage and other factors. Most of the patients are usually cured.

Intermediate Risk

  • 5 year survival 50-70%
  • It varies with tumor location, stage and age. Children 1 to 9 years of age usually do better than younger or older ones.

High Risk

  • 5 year survival 20-30%
  • It varies with tumor location, age of patient and type of tumor. Children 1-9 years of age, with limited spread and/or embryonal variant usually do better.

Treatment of Rhabdomyosarcoma

Pleomorphic RMSs are usually treated with a treatment approach similar to that for other STSs. For the treatment of embryonal and alveolar RMS, patients should refer to institutions with experience in treating RMS. 

All children and adults with RMS are treated with a multimodality treatment approach. Chemotherapy, surgery and/or radiotherapy is usually the part of the multimodality treatment approach. The surgery may be performed before chemotherapy, if possible, without any significant functional disability or other major cosmetic issues. 

Otherwise, chemotherapy and/or radiotherapy are employed as first-line treatment. In case of the sufficient shrinkage in the tumor to render it resectable, surgery may be employed to remove all cancerous tissue. All these treatments may be employed separately or in combination when the tumor continues to grow or comes back after the initial treatment.

Palliative Treatment

This may help in improving the overall quality of life by providing relief from the symptoms caused by the RMS. They are generally given as supportive care for advanced stage cancer. These include but are not limited to using drugs to reduce pain and other symptoms such as vomitingfatigue or external-beam radiation therapy for bleeding or pain, etc.

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