Cancer and S.I. Pain

Cancer in the pelvis can occur in a number of different ways. Pelvic cancer may begin as a primary tumor, most commonly as a chordoma, osteosarcoma, or myeloma. It can also metastasize from any primary tumor in the abdominal or pelvic cavity. The most common tumors to metastasize to the sacrum are from primary lung, breast, colorectal, and prostate tumors. The pelvis can also act as a depository for malignancies after incomplete removal of a primary carcinoma within the pelvis. In addition, recurrence of cancer can occur after surgical resection or radiotherapy of a pelvic neoplasm. 

Screening for Cancer

Sacral neoplasms are relatively rare and are usually not diagnosed early in the disease process due to symptoms resembling mild low back pain or sciatica. Screening for cancer in a patient with S.I. pain should begin with a complete review of the patient's past medical history. In the case of cancer as a cause of pelvic or S.I. pain, a past history of cancer is usually present. A history of cancer with recent surgical removal of tumor tissue followed by back, sacral, hip, or pelvic pain within the next 6 months is a major red flag. Immediate referral for medical evaluation is required, even if the pain appears to have a clear neuromuscular or musculoskeletal origin. 

Clinical Presentation

A common clinical presentation of pelvic cancer referring pain to the body will present as one or more of the following  pain descriptions in the sacrum, pelvis, or low back: deep aching, colicky, constant with varying waves of intensity, or diffuse pain. Typically, the patient will not be able to point to the painful area with one finger because the pain is not localized.

Step-by-Step Screening:
1: Examine the patient for the presence of red flags. Red flags are warning symptoms that indicate for the clinician to slow down and think about the need for screening. The presence of a single red flag is not usually cause for immediate medical attention. Each red flag should be viewed in the context of the whole patient, with respect to their age, gender, past medical history, clinical presentation, known risk factors, and associated signs and symptoms. 

2: Examine the patient for the presence of risk factors for disease, as well as associated signs and symptoms. 

3: Examine the patient for the presence or constitutional symptoms. Constitutional symptoms refer to a constellation of signs and symptoms present whenever the patient is experiencing a systemic illness. 

4:Conduct a Review of Systems. A Review of Systems is a dynamic part of the evaluation process in which the clinician makes clinical judgments based on the information gathered during the examination. The Review of systems is where the clinician recognizes clusters of signs and symptoms and determines the possible need for medical referral. During this process, all of the patient's complaints and associated signs and symptoms are categorized. The categorization process leads the therapist towards making an appropriate clinical decision on whether to treat the patient, treat and refer the patient, or simply refer the patient to the proper healthcare practitioner. 

Red Flags:

  • Personal or family history of cancer
  • Bacterial or viral infection within the last 6 weeks
  • Recurrent colds or flu with a cyclical pattern
  • History of immunosupression
  • No known cause, unknown etiology, insidious onset of symptoms
  • Symptoms are unrelieved or worsened by physical therapy intervention
  • Significant weight loss or gain without effort
  • Symptoms are unrelieved by rest or change in position
  • Unable to alter (provoke, reproduce, alleviate) symptoms during exam
  • Symptoms do not fit the expected mechanical or neuromusculoskeletal pain pattern
  • Postmenopausal vaginal bleeding (not due to hormone replacement therapy)
  • A growing mass (painless or painful) is cancer until proved otherwise 

2a: Risk Factors for Disease:

  • Substance or alcohol use/abuse
  • Tobacco use
  • Age 
  • Gender
  • Body Mass Index (BMI)
  • Exposure to radiation
  • Sedentary lifestyle
  • Race/Ethnicity
  • Domestic Violence
  • Hysterectomy/oophorectomy
  • Occupation

2b: Associated Signs and Symptoms of Cancer:

  • Recent report of confusion
  • Presence of constitutional symptoms (see below) or atypical vital signs
  • Proximal muscle weakness (especially if accompanied by change in DTR's)
  • Joint pain with skin rashes or nodules
  • Any cluster of signs and symptoms observed during the review of systems that are characteristic of a particular organ system
  • Unusual menstrual cycle or symptoms associated with menses
  • Change in bowel or bladder habits
* It is important that the clinician ask if the patient if there are any other symptoms or problems anywhere else in the body that are not related to the current problem.

3: Constitutional Symptoms:

  • Fever
  • Diaphoresis
  • Night sweats
  • Nausea
  • Vomiting
  • Diarrhea
  • Pallor
  • Dizziness/syncope
  • Fatigue
  • Weight loss

Review of Systems:

Questions the therapist should now review:
  • Do any red flags in the past medical history or clinical presentation suggest a systemic origin of symptoms?
  • Are any red flags also associated signs and symptoms of this pathology?
  • What additional screening tests or questions are needed (if any)?
  • Is referral to another healthcare needed, or is the therapist now clear to proceed with a planned intervention?
* Though it is not the responsibility of the physical therapist to identify the exact underlying pathology, the astute therapist will be able to recognize a problem outside the scope of physical therapy practice and make a timely and appropriate referral.  


Goodman, Catherine Cavallaro., and Teresa E. Kelly. Snyder. Differential Diagnosis for Physical Therapists: Screening for Referral. 4th ed. St. Louis, MO: Saunders/Elsevier, 2007. Print.